This module provides bindings to the Python programming language. Basic usage in the context of QtiPlot will be discussed below, but for more in-depth information on the language itself, please refer to its excellent documentation.
This file allows you to customize the Python environment, import modules and define functions and classes that will be available in all of your projects. The default initialization file shipped with QtiPlot imports Python's standard math functions as well as (if available) special functions from SciPy, the symbolic mathematics library SymPy and helper functions for RPy2. Also, it creates some handy shortcuts, like table("table1") for qti.app.table("table1").
When activating Python support, QtiPlot searches the initialization file in a default folder, which can be customized via the File Locations tab of the Preferences dialog. If the initialization file is not found, QtiPlot will issue a warning and muParser will be kept as the default interpreter.
Files ending in .pyc are compiled versions of the .py source files and therefore load a bit faster. The compiled version will be used if the source file is older or nonexistent. Otherwise, QtiPlot will try to compile the source file (if you've got write permissions for the output file).
Mathematical expressions work largely as expected. However, there's one caveat, especially when switching from muParser (which has been used exclusively in previous versions of QtiPlot): a^b does not mean "raise a to the power of b" but rather "bitwise exclusive or of a and b"; Python's power operator is **. Thus:
2^3 # read: 10 xor 11 = 01 #> 1 2**3 #> 8
One thing you have to know when working with Python is that indentation is very important. It is used for grouping (most other languages use either braces or keywords like do...end for this). For example,
x=23 for i in (1,4,5): x=i**2 print(x)will do what you would expect: it prints out the numbers 1, 16 and 25; each on a line of its own. Deleting just a bit of space will change the functionality of your program:
x=23 for i in (1,4,5): x=i**2 print(x)will print out only one number - no, not 23, but rather 25. This example was designed to also teach you something about variable scoping: There are no block-local variables in Python. All statements outside of any function use module scope; that is, variables attached to one column script or script window. All statements inside a function use that function's "local" scope, but they can also read module variables. System-wide globals are stored in the special variable
globals
. To store your own:globals.mydata = 5 print globals.mydataGlobal scope rules recently changed In older versions, write this instead:
global mydata mydata = 5 print mydata
The basic syntax for defining a function (for use within one particular note, for example) is
def answer(): return 42If you want your function to be accessible from other modules, you have to add it to the
globals
: def answer(): return 42 globals.answer = answerIf you have an older versions of QtiPlot, you have to declare it global before the definition:
global answer def answer(): return 42You can add your own function to QtiPlot's function list. We'll also provide a documentation string that will show up, for example, in the "set column values" dialog:
def answer(): "Return the answer to the ultimate question about life, the universe and everything." return 42 qti.mathFunctions["answer"] = answerIf you want to remove a function from the list, do:
del qti.mathFunctions["answer"]
Global scope rules recently changed In older versions, a function's local scope hid the module scope. That means that if you entered a function definition in a Note, you would not be able to access (neither reading nor writing) Note-local variables from within the function. However, you could access global variables as usual.
If-then-else decisions are entered as follows:
if x>23: print(x) else: print("The value is too small.")
You can do loops, too:
for i in range(1, 11): print(i)This will print out the numbers between 1 and 10 inclusively (the upper limit does not belong to the range, while the lower limit does).
Python comes with some basic mathematical functions that are automatically imported (if you use the initialization file shipped with QtiPlot). Along with them, the constants e (Euler's number) and pi (the one and only) are defined.
Table 7-5. Python: Supported Mathematical Functions
Name | Description |
---|---|
acos(x) | inverse cosine |
asin(x) | inverse sine |
atan(x) | inverse tangent |
atan2(y,x) | equivalent to atan(y/x), but more efficient |
ceil(x) | ceiling; smallest integer greater or equal to x |
cos(x) | cosine of x |
cosh(x) | hyperbolic cosine of x |
degrees(x) | convert angle from radians to degrees |
exp(x) | Exponential function: e raised to the power of x. |
fabs(x) | absolute value of x |
floor(x) | largest integer smaller or equal to x |
fmod(x,y) | remainder of integer division x/y |
frexp(x) | Returns the tuple (mantissa,exponent) such that x=mantissa*(2**exponent) where exponent is an integer and 0.5 <=abs(m)<1.0 |
hypot(x,y) | equivalent to sqrt(x*x+y*y) |
ldexp(x,y) | equivalent to x*(2**y) |
log(x) | natural (base e) logarithm of x |
log10(x) | decimal (base 10) logarithm of x |
modf(x) | return fractional and integer part of x as a tuple |
pow(x,y) | x to the power of y; equivalent to x**y |
radians(x) | convert angle from degrees to radians |
sin(x) | sine of x |
sinh(x) | hyperbolic sine of x |
sqrt(x) | square root of x |
tan(x) | tangent of x |
tanh(x) | hyperbolic tangent of x |
We will assume that you are using the initialization file shipped with QtiPlot. Accessing the objects in your project is straight-forward,
t = table("Table1") m = matrix("Matrix1") g = graph("Graph1") p = plot3D("Graph2") n = note("Notes1") # get a pointer to the QTextEdit object used to display information in the results log window: log = resultsLog() # display some information in the data display toolbar: displayInfo(text) # get a pointer to the QLineEdit object in the data display toolbar and access the information displayed: info = infoLineEdit() text = info.text()as is creating new objects:
# create an empty table named "tony" with 5 rows and 2 columns: t = newTable("tony", 5, 2) # use defaults t = newTable() # create an empty matrix named "gina" with 42 rows and 23 columns: m = newMatrix("gina", 42, 23) # use defaults m = newMatrix() # create an empty graph window g = newGraph() # create a graph window named "test" with two layers disposed on a 2 rows x 1 column grid g = newGraph("test", 2, 2, 1) # create an empty 3D plot window with default title p = newPlot3D() # create an empty note named "momo" n = newNote("momo") # use defaults n = newNote()The currently selected Table/Matrix etc. can be accessed with the following commands:
t = currentTable() m = currentMatrix() g = currentGraph() n = currentNote()The functions will only return a valid object if a window of the wanted type is actually selected. You can check if the object is valid with a simple if clause:
if isinstance(t,qti.Table): print "t is a table"
Every piece of code is executed in the context of an
object which you can access via the self
variable. For example,
entering self.cell("t",i) as a column formula is equivalent to the convenience
function col("t").
t = table("Table1") setWindowName(t, "toto") t.setWindowLabel("tutu") t.setCaptionPolicy(MDIWindow.Both)The caption policy can have one of the following values:
the window caption is determined by the window name
the caption is determined by the window label
caption = "name - label"
t = table("Table1") t.setGeometry(10, 10, 800, 600) print t.x(), t.y(), t.width(), t.height()For a fast editing process, you can create template files from existing tables, matrices or plots. The templates can be used later on in order to create customized windows very easily:
saveAsTemplate(graph("Graph1"), "my_plot.qpt") g = openTemplate("my_plot.qpt")Also, you can easily clone a MDI window:
g1 = clone(graph("Graph1"))If you want to delete a project window, you can use the close()method. You might want to deactivate the confirmation message, first:
w.confirmClose(False) w.close()All QtiPlot subwindows are displayed in a QMdiArea. You can get a pointer to this object via the workspace()method. This can be particularly usefull if you need to customize the behavior of the workspace via your scripts. Here follows a small example script that pops-up a message displaying the name of the active MDI subwindow each time a new window is activated:
def showMessage(): QtGui.QMessageBox.about(qti.app, "", workspace().activeSubWindow().objectName()) QtCore.QObject.connect(workspace(), QtCore.SIGNAL("subWindowActivated(QMdiSubWindow *)"), showMessage)
f = activeFolder()The functions table, matrix, graph and note will start searching in the active folder and, failing this, will continue with a depth-first recursive search of the project's root folder, given by:
f = rootFolder()In order to access subfolders and windows, there are the following functions:
f2 = f.folders()[number] f2 = f.folder(name, caseSensitive=True, partialMatch=False) t = f.table(name, recursive=False) m = f.matrix(name, recursive=False) g = f.graph(name, recursive=False) n = f.note(name, recursive=False)If you supply True for the recursive argument, a depth-first recursive search of all subfolders will be performed and the first match returned.
New folders can be created using:
newFolder = addFolder("New Folder", parentFolder = 0)If the
parentFolder
is not specified, the new folder will be added as a subfolder of the project's
root folder. When you create a new folder via a Python script, it doesn't automatically become the active folder
of the project. You have to set this programatically, using:
changeFolder(newFolder, bool force=False)Folders can be deleted using:
deleteFolder(folder)You can save a folder as a project file, and of course, you can also save the whole project:
saveFolder(folder, "new_file.qti", compress=False) saveProjectAs("new_file_2.qti", compress=False)If
compress
is set to True, the project file will be archived to the .gz format, using zlib.
Also, you can load a QtiPlot or an Origin project file into a new folder.
The new folder will have the base name of the project file and will be added as a subfolder
to the parentFolder
or to the current folder if no parent folder is specified.
newFolder = appendProject("projectName", parentFolder = 0)If you don't want to be asked for confirmation when a table/matrix is renamed during this operation, or when deleting a folder via a Python script, you must change your preferences concerning prompting of warning messages, using the Preferences dialog ("Confirmations" tab).
Folders store their own log information containing the results of the analysis operations performed on the child windows. This information is updated in the result log window each time you change the active folder in the project. You can access and manipulate these log strings via the following functions:
text = folder.logInfo() folder.appendLogInfo("Hello!") folder.clearLogInfo()
t
. You can access its numeric cell values with
t.cell(col, row) # and t.setCell(col, row, value)
Whenever you have to specify a column, you can use either the column name (as a string) or the consecutive column number (starting with 1). Row numbers also start with 1, just as they are displayed. In many places there is an alternative API which represents a table as a Python sequence is provided. Here rows are addressed by Python indices or slices which start at 0. These places are marked as such.
If you want to work with arbitrary texts or the textual representations of numeric values, you can use:t.text(col, row) # and t.setText(col, row, string)An alternative way to get/set the value of a cell is using the format of the column (Text, Numeric, ...). Qtiplot handles all the casting under the hood and throws an
TypeError
if this isn't possible.
Assigning None
will clear the cell's value.
The column type Day-of-Week returns/accepts the numbers 1 (monday) to 7 (sunday, for which also 0 is accepted).
The column type Month returns/accepts the numbers 1 to 12.
The column type Date returns/accepts datetime.datetime
objects and also accepts a QDateTime
.
The column type Time returns/accepts datetime.time
objects and also accepts a QTime
.
t.cellData(col, row) # and t.setCellData(col, row, value)The number of columns and rows is accessed via:
t.numRows() # same as len(t) t.numCols() t.setNumRows(number) t.setNumCols(number)You can add a new column at the end of the table or you can insert new columns before a
startColumn
using the functions below:
t.addColumn() t.insertColumns(startColumn, count)Adding an empty row at the end of the table is done with the
addRow()
method.
It returns the new row number.
newRowIndex = t.addRow()If you need all the data of a row or column you can use the
rowData()
and colData()
methods. This is much faster then iterating manually over the cells.
Alternatively you can use the []
operator in combination with Python indices or slices,
which start at 0.
valueList = t.colData(col) # col may be a string or a number starting at 1 rowTuple = t.rowData(row) # row number starting at 1 rowTuple = t[idx] # row index starts at 0 rowTupleList = t[slice]A Table is iterable. The data is returned row wise as tuple.
for c1, c2, c3 in t: # do stuff, assuming t has three columnsIt is possible to assign random or normal random values to a complete column or to a subset of rows in a column:
t.setRandomValues(col, startRow = 1, endRow = -1) t.setNormalRandomValues(col, startRow = 1, endRow = -1, standardDeviation = 1.0)Assigning values to a complete row or column is also possible. While the new row data has to be a tuple which length must match the column number, column data just has to be iteratable. If the iterator stops before the end of the table is reached, a
StopIteration
exception is raised.
In combination with the offset
this allows to fill a column chunk wise.
A positive offset starts filling the column after this row number.
A negative offset ignores the firsts values of the iterator.
t.setColData(col, iterableValueSequence, offset=0) # just fill the first column with a list of values, staring at row 6 t.setColData(1, [12,23,34,56,67], 5) # fill the second column with Fibonacci numbers, omitting the first three. def FibonacciGenerator(): a, b = 1, 1 while True: a, b = b, a+b yield a t.setColData(2, FibonacciGenerator(), -3) t.setRowData(row, rowTuple) # row starts at 1 # assuming t has exactly two columns... t.setRowData(2, (23, 5)) # fill the second row t[1] = 23, 5 # using a Python index, starting at 0 # adding a new row and set it's values t.appendRowData(rowTuple)You can set the format of a column to text using:
t.setColTextFormat(col)Or you can adjust the numeric format:
t.setColNumericFormat(col, format, precision, update=True)were
col
is the number of the column to adjust and precision
states the number of digits.
The format
can be one of the following:
standard format
decimal format with precision
digits
scientific format
t.setColDateFormat(col, format, update=True) t.setColDateFormat("col1", "yyyy-MM-dd HH:mm")were
col
is the name/number of a column and format
the format string.
In this string, the following placeholder are recognized:
the day as number without a leading zero (1 to 31)
the day as number with a leading zero (01 to 31)
the abbreviated localized day name (e.g. 'Mon' to 'Sun')
the long localized day name (e.g. 'Monday' to 'Sunday')
the month as number without a leading zero (1-12)
the month as number with a leading zero (01-12)
the abbreviated localized month name (e.g. 'Jan' to 'Dec')
the long localized month name (e.g. 'January' to 'December')
the year as two digit number (00-99)
the year as four digit number
the hour without a leading zero (0 to 23 or 1 to 12 if AM/PM display)
the hour with a leading zero (00 to 23 or 01 to 12 if AM/PM display)
the hour without a leading zero (0 to 23, even with AM/PM display)
the hour with a leading zero (00 to 23, even with AM/PM display)
the minute without a leading zero (0 to 59)
the minute with a leading zero (00 to 59)
the second without a leading zero (0 to 59)
the second with a leading zero (00 to 59)
the milliseconds without leading zeroes (0 to 999)
the milliseconds with leading zeroes (000 to 999)
interpret as an AM/PM time. AP must be either "AM" or "PM".
interpret as an AM/PM time. ap must be either "am" or "pm".
t.setColTimeFormat(col, format, update=True) t.setColTimeFormat(1, "HH:mm:ss")... a month ...
t.setColMonthFormat(col, format, update=True) t.setColMonthFormat(1, "M")Here the format is the following:
Only the first letter of the month, i.e. "J"
The short form, like "Jan"
The full name, "January"
t.setColDayFormat(col, format, update=True) t.setColDayFormat(1, "ddd")Here the format is the following:
Only the first letter of the day, i.e. "M"
The short form, like "Mon"
The full name, "Monday"
t.swapColumns(column1, column2)You can delete a column or a range of rows using the functions below:
t.removeCol(number) t.deleteRows(startRowNumber, endRowNumber)It is also possible to use Python's
del
statement to remove rows.
Note that in this case a Python index or slice (instead of row numbers) is used, which start at 0.
del t[5] # deletes row 6 del t[0:4] # deletes row 1 to 5Column names can be read and written with:
t.colName(number) t.colNames() t.setColName(col, newName, enumerateRight=False) t.setColNames(newNamesList)If
enumerateRight
is set to True, all the table columns starting from index
col
will have their names modified to a combination of the
newName
and a numerical increasing index. If this parameter is not specified,
by default it is set to False.
The plural forms get/set all headers at once.
You can change the plot role of a table column (abscissae, ordinates, error bars, etc...) using:
t.setColumnRole(col, role)where
role
specifies the desired column role:
Table.None
Table.X
Table.Y
Table.Z
Table.xErr
Table.yErr
Table.Label
You can normalize a single column or all columns in a table:
t.normalize(col) t.normalize()Sort a single or all columns:
t.sortColumn(col, order = 0) t.sort(type = 0, order = 0, leadingColumnName)
file
, using sep
as separator char, ignoring
ignoreLines
lines at the head of the file and all lines starting with a comment
string.
t.importASCII(file, sep="\t",ignoreLines=0,renameCols=False,stripSpaces=True,simplifySpace=False, importComments=False,comment="#",readOnly=False,importAs=Table.Overwrite,locale=QLocale(),endLine=0,maxRows=-1)As you see from the above list of import options, you have the possibility to set the new columns as read-only. This will prevent the imported data from being modified. You have the possibility to remove this protection at any time, by using:
t.setReadOnlyColumn(col, False)
The importAs
flag can have the following values:
Table.NewColumns: data values are added as new columns.
Table.NewRows: data values are added as new rows.
Table.Overwrite: all existing values are overwritten (default value).
The endLine
flag specifies the end line character convention used in the ascii file.
Possible values are: 0 for line feed (LF), which is the default value,
1 for carriage return + line feed (CRLF) and 2 for carriage return only (usually on Mac computers).
The last parameter maxRows
allows you to specify a maximum number of imported
lines. Negative values mean that all data lines must be imported.
If the decimal separator of the imported file does not match the currently used conventions, you have to adjust them before using the table:
t.setDecimalSeparators(country,ignoreGroupSeparator=True)
Where country can have one of the following values:
Use the system value
Use the following format: 1,000.00
Use the following format: 1.000,00
Use the following format: 1 000,00
It is possible to import a sheet from an Excel .xls file file
to a table, using:
t = importExcel(file, sheet)
If the integer sheet
variable is not specified, all non-empty sheets in the Excel workbook are imported
into separate tables and a reference to the table containing the data from the last sheet is returned.
It is possible to import a sheet from an ODF spreadsheet .ods file
to a table, using:
t = importOdfSpreadsheet(file, sheet)
If the integer sheet
variable is not specified, all non-empty sheets in the spreadsheet are imported
into separate tables and a reference to the table containing the data from the last sheet is returned.
You can export values from a table to an ASCII file
, using
sep
as separator character. The ColumnLabels
option
allows you to export or ignore the column labels, ColumnComments
does the same for the comments
displayed in the table header and the SelectionOnly
option makes
possible to export only the selected cells of the table.
t.exportASCII(file,sep="\t",ignore=0,ColumnLabels=False,ColumnComments=False,SelectionOnly=False)Other settings that you can modify are the text displayed as a comment in the header of a column...
t.setComment(col, newComment)... or the expression used to calculate the column values. Please beware that changing the command doesn't automatically update the values of the column; you have to call
recalculate
explicitly.
Calling it with just the column as argument will recalculate every row. Forcing muParser can speed things up.
t.setCommand(col, newExpression) t.recalculate(col, startRow=1, endRow=-1, forceMuParser=False, notifyChanges=True)
t.comment(col) t.showComments(on = True)You can also modify the width of a column (in pixels) or hide/show table columns:
t.setColumnWidth(col, width) t.hideColumn(col, True)If one or several table columns are hidden you can make them visible again using:
t.showAllColumns()You can ensure the visibility of a cell with:
t.scrollToCell(col, row)After having changed some table values from a script, you will likely want to update dependent Graphs:
t.notifyChanges()As a simple example, let's set some column values without using the dialog.
t = table("table1") for i in range(1, t.numRows()+1): t.setCell(1, i, i**2) t.notifyChanges()While the above is easy to understand, there is a faster and more pythonic way of doing the same:
t = table("table1") t.setColData(1, [i*i for i in range(len(t))]) t.notifyChanges()You can check if a column or row of a table is selected by using the following functions:
t.isColSelected(col) t.isRowSelected(row)
df <- read.table("/some/path/data.csv", header=TRUE) m <- mean(df) v <- var(df) source("/some/path/my_func.r") new_df <- my_func(df, foo=bar)... and now the same from within QtiPlot:
df = table("Table1").toRDataFrame() print R.mean(df), R.var(df) R.source("/some/path/my_func.r") new_df = R.my_func(df, foo=bar) newTableFromRDataFrame(new_df, "my result table")
m
, you can change its display mode via the following function:
m.setViewType(Matrix.TableView) m.setViewType(Matrix.ImageView)If a matrix is viewed as an image, you have the choice to display it either as gray scale or using a predefined color map:
m.setGrayScale() m.setRainbowColorMap() m.setDefaultColorMap() # default color map defined via the 3D plots tab of the preferences dialogYou can also define custom color maps:
map = LinearColorMap(QtCore.Qt.yellow, QtCore.Qt.blue) map.setMode(LinearColorMap.FixedColors) # default mode is LinearColorMap.ScaledColors map.addColorStop(0.2, QtCore.Qt.magenta) map.addColorStop(0.7, QtCore.Qt.cyan) m.setColorMap(map)You have direct access to the color map used for a matrix via the following functions:
map = m.colorMap() col1 = map.color1() print col1.green() col2 = map.color2() print col2.blue()Accessing cell values is very similar to Table, but since Matrix doesn't use column logic, row arguments are specified before columns and obviously you can't use column name.
m.cell(row, col) m.setCell(row, col, value) m.text(row, col) m.setText(row, col, string)An alternative solution to assign values to a Matrix, would be to define a formula and to calculate the values using this formula, like in the following example:
m.setFormula("x*y*sin(x*y)") m.calculate()You can also specify a column/row range in the calculate() function, like this:
m.calculate(startRow, endRow, startColumn, endColumn)Before setting the values in a matrix you might want to define the numeric precision, that is the number of significant digits used for the computations:
m.setNumericPrecision(prec)You can change the dimensions of a matrix:
m.setDimensions(rows, columns) m.setNumRows(rows) m.setNumCols(columns)Also, like with tables, you can access the number of rows/columns in a matrix:
rows = m.numRows() columns = m.numCols()If QtiPlot has been built with support for ALGLIB, you can also change the dimensions of a matrix by resampling it, using bilinear or bicubic interpolation:
m.resample(rows, cols)# bilinear interpolation by default m.resample(rows, cols, 1) # bicubic interpolationIf ALGLIB is available you can also smooth the matrix data using:
m.smooth()Matrix objects allow you to define a system of x/y coordinates that will be used when plotting color/contour maps or 3D height maps. You can manipulate these coordinates using the following functions:
xs = m.xStart() xe = m.xEnd() ys = m.yStart() ye = m.yEnd() m.setCoordinates(xs + 2.5, xe, ys - 1, ye + 1)The horizontal and vertical headers of a matrix can display either the x/y coordinates or the column/row indexes:
m.setHeaderViewType(Matrix.ColumnRow) m.setHeaderViewType(Matrix.XY)There are several built-in transformations that you can apply to a matrix object. You can transpose or invert a matrix and calculate its determinant, provided, of course, that the conditions on the matrix dimensions, required by these operations, are matched:
m.transpose() m.invert() d = m.determinant()Some other operations, very useful when working with images, like 90 degrees rotations and mirroring, can also be performed. By default rotations are performed clockwise. For a counterclockwise rotation you must set the
clockwise
parameter to False
.
m.flipVertically() m.flipHorizontally() m.rotate90(clockwise = True)Please note that sometimes, after a change in the matrix settings, you need to use the following function in order to update the display:
m.resetView()If you need to get data from a table, in order to use it in a matrix (or vice-versa), you can avoid time consuming copy/paste operations and speed up the whole process by simply converting the table into a matrix:
m = tableToMatrix(table("Table1")) t = matrixToTable(m)For the production of contour plots, you can convert a regular XYZ data table ("regular", meaning that cells in the X and Y columns of the table define a regular 2D grid) into a matrix:
m = tableToMatrixRegularXYZ(table("Table1"), "Table1_3")Also, it's worth knowing that you can easily import image files to matrices, that can be used afterwards for plotting (see the next section for more details about 2D plots):
m1 = importImage("C:/poze/adi/PIC00074.jpg") m2 = newMatrix() m2.importImage("C:/poze/adi/PIC00075.jpg")The algorithm used to import the image returns a gray value between 0 and 255 from the (r, g, b) triplet corresponding to each pixel. The gray value is calculated using the formula: (r * 11 + g * 16 + b * 5)/32
For custom image analysis operations, you can get a copy of the matrix image view, as a QImage object, via:
image = m.image()You can export matrices to all raster image formats supported by Qt or to any of the following vectorial image format: EPS, PS, PDF or SVG using:
m.export(fileName)This is a shortcut function which uses some default parameters in order to generate the output image. If you need more control over the export parameters you must use one of the following functions:
m1.exportRasterImage(fileName, quality = 100, dpi = 0, compression = 0) m2.exportVector(fileName, resolution, color = True), where the
quality
parameter influences the size of the output file.
The higher this value (maximum is 100), the higher the quality of the image, but the larger the size of the resulting files.
The dpi
parameter represents the export resolution in pixels per inch (the default is screen resolution).
The compression
parameter can be 0 (no compression) or 1 (LZW) and is only effectif for .tif/.tiff images.
It is neglected for all other raster image formats.
You can also import an ASCII data file
, using sep
as separator characters, ignoring
ignore
lines at the head of the file and all lines starting with a comment
string:
m.importASCII(file, sep="\t", ignore=0, stripSpaces=True, simplifySpace=False, comment="#", importAs=Matrix.Overwrite, locale=QLocale(), endLine=0, maxRows=-1)
The importAs
flag can have the following values:
Matrix.NewColumns: data values are added as new columns.
Matrix.NewRows: data values are added as new rows.
Matrix.Overwrite: all existing values are overwritten (default value).
locale
parameter can be used to specify the convention for decimal separators used in your ASCII file.The endLine
flag specifies the end line character convention used in the ascii file.
Possible values are: 0 for line feed (LF), which is the default value,
1 for carriage return + line feed (CRLF) and 2 for carriage return only (usually on Mac computers).
The last parameter maxRows
allows you to specify a maximum number of imported
lines. Negative values mean that all data lines must be imported.
Also, you can export values from a matrix to an ASCII file
, using
sep
as separator characters. The SelectionOnly
option makes
possible to export only the selected cells of the matrix.
m.exportASCII(file, sep="\t", SelectionOnly=False)
A stem-plot (or stem-and-leaf plot), in statistics, is a device for presenting quantitative data in a graphical format, similar to a histogram, to assist in visualizing the shape of a distribution. A basic stem-plot contains two columns separated by a vertical line. The left column contains the stems and the right column contains the leaves. See Wikipedia for more details.
QtiPlot provides a text representation of a stem-plot. The following function returns a string of characters representing the statistical analysis of the data:
text = stemPlot(Table *t, columnName, power = 1001, startRow = 0, endRow = -1)where the
power
variable is used to specify the stem unit as a power of 10.
If this parameter is greater than 1000 (the default behavior), than QtiPlot will
try to guess the stem unit from the input data and will pop-up a dialog asking you to
confirm the automatically detected stem unit.
Once you have created the string representation of the stem-plot, you can display it in any text editor you like: in a note within the project or even in the results log:
resultsLog().append(stemPlot(table("Table1"), "Table1_2", 1, 2, 15))
t = table("Table1") g = plot(t, column, type)
type
specifies the desired plot type and can be one of the following numbers or the equivalent reserved word:
Layer.Line
Layer.Scatter
Layer.LineSymbols
Layer.VerticalBars
Layer.Area
Layer.Pie
Layer.VerticalDropLines
Layer.Spline
Layer.HorizontalSteps
Layer.Histogram
Layer.HorizontalBars
Layer.Box
Layer.VerticalSteps
g1 = plot(table("Table1"), (2,4,7), 2) g2 = plot(table("Table1"), ("Table1_2","Table1_3"), Layer.LineSymbols)All the curves in a plot layer can be customized in terms of color, line width and line style. Here's a short script showing the corresponding functions at work:
t = newTable("test", 30, 4) for i in range(1, t.numRows()+1): t.setCell(1, i, i) t.setCell(2, i, i) t.setCell(3, i, i+2) t.setCell(4, i, i+4) l = plot(t, (2,3,4), Layer.Line).activeLayer() # plot columns 2, 3 and 4 for i in range(0, l.numCurves()): l.setCurveLineColor(i, 1 + i) #curve color is defined as an integer value l.setCurveLineWidth(i, 0.5 + 2*i) l.setCurveLineStyle(1, QtCore.Qt.DotLine) l.setCurveLineStyle(2, QtCore.Qt.DashLine)You can also create a vector plot by giving four columns in a Python tuple as an argument and the plot type as Layer.VectXYXY (11) or Layer.VectXYAM (14), depending on how you want to define the end point of your vectors: using (X, Y) coordinates or (Angle, Magnitude) coordinates.
g = plot(table("Table1"), (2,3,4,5), Layer.VectXYXY)If you want to add a curve to an existing Graph window, you have to choose the destination layer. Usually,
l = g.activeLayer()will do the trick, but you can also select a layer by its number:
l = g.layer(num)
l.setTitle("My beautiful plot") l.setTitleFont(QtGui.QFont("Arial", 12)) l.setTitleColor(QtGui.QColor("red")) l.setTitleAlignment(QtCore.Qt.AlignLeft)The alignment parameter can be any combination of the Qt alignment flags (see the PyQt documentationfor more details).
If you want you can remove the plot title using:
l.removeTitle()Here's how you can add greek symbols in the plot title or in any other text in the plot layer: axis labels, legends:
l.setTitle("normal text <font face=\"Symbol\">greek text</font>")Using the font specifications, you can also change the color of some parts of the title only:
l=newGraph().activeLayer() l.setTitle("<font color = red>red</font> <font color = yellow>yellow</font> <font color = blue>blue</font>")
l.enableAxis(int axis, on = True)where
axis
can be any integer value between 0 and 3 or the equivalent reserved word:
Layer.Left
Layer.Right
Layer.Bottom
Layer.Top
l.setAxisTitle(axis, "My axis title") l.setAxisTitleFont(axis, QtGui.QFont("Arial", 11)) l.setAxisTitleColor(axis, QtGui.QColor("blue")) l.setAxisTitleAlignment(axis, alignFlags)its color and the font used for the tick labels:
l.setAxisColor(axis, QtGui.QColor("green")) l.setAxisFont(axis, QtGui.QFont("Arial", 10))The tick labels of an axis can be enabled or disabled, you can set their color and their rotation angle:
l.enableAxisLabels(axis, on = True) l.setAxisLabelsColor(axis, QtGui.QColor("black")) l.setAxisLabelRotation(axis, angle)
angle
can be any integer value between -90 and 90 degrees.
A rotation angle can be set only for horizontal axes (Bottom and Top).
The numerical format of the labels can be set using:
l.setAxisNumericFormat(axis, format, precision = 6, formula)where
format
can have the following values: Automatic: the most compact numeric representation is chosen
Decimal: numbers are displayed in floating point form
Scientific: numbers are displayed using the exponential notation
Superscripts: like Scientific, but the exponential part is displayed as a power of 10
precision
is the number of significant digits and
formula
is a mathematical expression that can be used to link opposite scales. It's
argument must be x
for horizontal axes and y
for vertical axes.
For example, assuming that the bottom axis displays a range of wavelengths in nanometers and that the top
axis represents the equivalent energies in eV, with the help of the code below all the wavelengths
will be automatically converted to electron-volts and the result will be displayed in floating point form
with two significant digits after the decimal dot sign:
l.setAxisNumericFormat(Layer.Top, 1, 2, "1239.8419/x")The axis ticks can be customized via the following functions:
l.setTicksLength(minLength, majLength) l.setMajorTicksType(axis, majTicksType) l.setMinorTicksType(axis, minTicksType) l.setAxisTicksLength(axis, majTicksType, minTicksType, minLength, majLength)where the
majTicksType
and minTicksType
parameters specify the
desired orientation for the major and minor ticks, respectively:
Layer.NoTicks
Layer.Out: outward orientation for ticks, with respect to the plot canvas
Layer.InOut: both inward and outward ticks
Layer.In: inward ticks
minLength
specifies the length of the minor ticks, in pixels and
majLength
the length of the major ticks.
You can also customize the scales of the different axes using:
l.setScale(int axis, double start, double end, double step=0.0, int majorTicks=5, int minorTicks=5, int type=0, bool inverted=False)where
type
specifies the desired scale type: Layer.Linear
Layer.Log10
Layer.Ln
Layer.Log2
Layer.Reciprocal
Layer.Probability
Layer.Logit
step
defines the size of the interval between the major scale ticks. If not specified (default value is 0.0), the step size is calculated automatically.
The other flags should be self-explanatory.Defining a scale range for an axis doesn't automatically disable autoscaling.
This means that if a curve is added or removed from the layer, the axes will still automatically
adapt to the new data interval. This can be avoided by disabling the autoscaling mode, thus
making sure that your scale settings will always be taken into account:
l.enableAutoscaling(False)If you want to rescale the plot layer so that all the data points are visible, you can use the following utility function:
l.setAutoScale()The same
setScale
function above, with a longer list of arguments,
can be used to define an axis break region:
l.setScale(axis, start, end, step=0.0, majorTicks=5, minorTicks=5, type=0, inverted=False, left=-DBL_MAX, right=DBL_MAX, breakPosition=50, stepBeforeBreak=0.0, stepAfterBreak=0.0, minTicksBeforeBreak=4, minTicksAfterBreak=4, log10AfterBreak=False, breakWidth=4, breakDecoration=True)where
left
specifies the left limit of the break region,
right
the right limit,
breakPosition
is the position of the break expressed as a percentage of the axis length and
breakWidth
is the width of the break region in pixels.
The names of the other parameters should be self-explanatory.
Finally, you can specify the width of all axes and enable/disable the drawing of their backbone line, using:
l.setAxesLinewidth(2) l.drawAxesBackbones(True)
l.setCanvasFrame(2, QtGui.QColor("red")) l.setCanvasColor(QtGui.QColor("lightGrey")) l.setCanvasBackgroundImage("C:/qtiplot/qtiplot/qtiplot_logo.png")The following access methods are available for the canvas background image:
pic = l.backgroundPixmap() # QPixmap path = l.canvasBackgroundFileName()Drawing the canvas frame and disabling the axes backbone lines is the only possible solution for the issue of axes not touching themselves at their ends.
l.setFrame(2, QtGui.QColor("blue")) l.setBackgroundColor(QtGui.QColor("grey"))The default spacing between the layer frame and the other layer elements (axes, title) can be changed via:
l.setMargin(10)
l.showGrid(axis) l.showGrid() l.setGridOnTop(on = True, update = True) # draw grid on top of dataThis will display the grid with the default color, width and pen style settings. If you need to change these settings, as well as to enable/disable certain grid lines, you can use the following functions:
grid = l.grid() grid.setMajPenX(QtGui.QPen(QtCore.Qt.red, 1)) grid.setMinPenX(QtGui.QPen(QtCore.Qt.yellow, 1, QtCore.Qt.DotLine)) grid.setMajPenY(QtGui.QPen(QtCore.Qt.green, 1)) grid.setMinPenY(QtGui.QPen(QtCore.Qt.blue, 1, QtCore.Qt.DashDotLine)) grid.enableXMax(True) grid.enableXMin() grid.enableYMax() grid.enableYMin(False) grid.enableZeroLineX(True) grid.enableZeroLineY(False) grid.setXZeroLinePen(QtGui.QPen(QtCore.Qt.black, 2)) grid.setYZeroLinePen(QtGui.QPen(QtCore.Qt.black, 2)) l.replot()All the grid functions containing an
X
refer to the vertical grid lines, whereas the Y
letter indicates the horizontal ones.
Also, the Maj
word refers to the main grid lines and Min
to the secondary grid.
legend = l.newLegend() #or legend = l.newLegend("enter your text here")Plot legends are special text objects which are updated each time you add or remove a curve from the layer. They have a special
auto-update
flag which is enabled by default.
The following function returns True
for a legend object:
legend.isAutoUpdateEnabled()You can disable/enable the auto-update behavior of a legend/text object using:
legend.setAutoUpdate(False/True)You can add common texts like this:
text = l.addText(legend) text.setOrigin(legend.x(), legend.y()+50)Please notice that the
addText
function returns a different reference
to the new text object. You can use this new reference later on in order to remove the text:
l.remove(text)Once you have created a legend/text, it's very easy to customize it. If you want to modify the text you can use:
legend.setText("Enter your text here")All other properties of the legend: rotation angle, text color, background color, frame style, font and position of the top-left corner can be modified via the following functions:
legend.setAngle(90) legend.setTextColor(QtGui.QColor("red")) legend.setBackgroundColor(QtGui.QColor("yellow")) legend.setFrameStyle(Frame.Shadow) legend.setFrameColor(QtCore.Qt.red) legend.setFrameWidth(3) legend.setFrameLineStyle(QtCore.Qt.DotLine) legend.setFont(QtGui.QFont("Arial", 14, QtGui.QFont.Bold, True)) # set top-left position using scale coordinates: legend.setOriginCoord(200.5, 600.32) # or set top-left position using pixel coordinates: legend.setOrigin(5, 10) legend.repaint()Other frame styles available for legends are:
Legend.Line
, which draws a rectangle around the text
and Legend.None
(no frame at all).
There is also a function allowing you to add an automatically built time stamp:
timeStamp = l.addTimeStamp()
l.setAntialiasing(True, bool update = True)
l.resize(200, 200); l.resize(QSize(w, h))If you also need to reposition the layer, you can use the following functions, where the first two arguments specify the new position of the top left corner of the canvas:
l.setGeometry(100, 100, 200, 200); l.setGeometry(QRect(x, y, w, h));The default behavior of 2D plot layers, with respect to the resizing of the graph window is to adapt the sizes of the fonts used for the various texts, to the new size of the plot window. You can override this behavior and keep the size of the fonts unchanged:
l.setAutoscaleFonts(False)
l.setCanvasSize(200, 200); l.setCanvasSize(QSize(w, h))If you also need to reposition the canvas, you can use the following functions, where the first two arguments specify the new position of the top left corner of the canvas:
l.setCanvasGeometry(100, 100, 200, 200); l.setCanvasGeometry(QRect(x, y, w, h));Please keep in mind that the fonts of the layer are not rescaled when you resize the layer canvas using the above methods.
l.insertCurve(table, Ycolumn, type=Layer.Scatter, int startRow = 0, int endRow = -1)# returns a reference to the inserted curve l.insertCurve(table, Xcolumn, Ycolumn, type=Layer.Scatter, int startRow = 0, int endRow = -1)# returns a reference to the inserted curve l.addCurve(table, column, type=Layer.Line, lineWidth = 1, symbolSize = 3, startRow = 0, endRow = -1)# returns True on success l.addCurves(table, (2,4), type=Layer.Line, lineWidth = 1, symbolSize = 3, startRow = 0, endRow = -1)# returns True on success l.removeCurve(curveName) l.removeCurve(curveIndex) l.removeCurve(curveReference) l.deleteFitCurves()It is possible to change the order of the curves inserted in a layer using the following functions:
l.changeCurveIndex(int oldIndex, int newIndex) l.reverseCurveOrder()If the table column used to create a plot curve has empty cells, you can choose whether the curve line is drawn connected across the missing data or not. This behavior can be specified using:
l.showMissingDataGap(on = True, replot = True)Sometimes, when performing data analysis, one might need the curve title. It is possible to obtain it using the method below:
title = l.curveTitle(curveIndex)It is possible to get a reference to a curve on the layer l using it's index or it's title, like shown below:
c = l.curve(curveIndex) c = l.curve(curveTitle) dc = l.dataCurve(curveIndex)
Please, keep in mind the fact that the above methods might return an invalid reference if the curve with the specified index/title is not a PlotCurve or a DataCurve object, respectively. For example, an analytical function curve is a PlotCurve but not a DataCurve and spectrograms are a completely different type of plot items which are neither PlotCurves nor DataCurves.
Use the following function to change the axis attachment of a curve:
l.setCurveAxes(number, x-axis, y-axis)
where number is the curve's number, x-axis is either 0 or 1 (bottom or top) and y-axis is either 0 or 1 (left or right).
In case you need the number of curves on a layer, you can get it withl.numCurves()Once you have added a curve to a 2D plot, you can fully customize it's appearance:
l = newGraph().activeLayer() l.setAntialiasing() c = l.insertCurve(table("Table1"), "Table1_2", Layer.LineSymbols) c.setPen(QtGui.QPen(Qt.red, 3)) c.setBrush(QtGui.QBrush(Qt.darkYellow)) c.setSymbol(PlotSymbol(PlotSymbol.Hexagon, QtGui.QBrush(Qt.yellow), QtGui.QPen(Qt.blue, 1.5), QtCore.QSize(15, 15)))It is possible to change the number of symbols to be displayed for a curve using the function below. This option can be very usefull for very large data sets:
c.setSkipSymbolsCount(3) print c.skipSymbolsCount()An alternative way of customizing a curve is by using the functions below:
l.setCurveLineColor(int curve, int color) # uses the index of the colors in the default QtiPlot color list: 0 = black, 1 = red, 2 = green, etc... l.setCurveLineStyle(int curve, Qt::PenStyle style) l.setCurveLineWidth(int curve, double width)You can also define a global color policy for the plot layer using the following convenience functions:
l.setGrayScale() l.setIndexedColors() # uses the colors in the default QtiPlot color list: 0 = black, 1 = red, 2 = green, etc...You can display labels showing the y values for each data point in a DataCurve:
c.setLabelsColumnName("Table1_2") c.setLabelsOffset(50, 50) c.setLabelsColor(Qt.red) c.setLabelsFont(QtGui.QFont("Arial", 14)) c.setLabelsRotation(45) c.loadData() # creates the labels and updates the displayand, of course, you can disable them using:
c.clearLabels() l.replot() # redraw the plot layer objectIf you need to change the range of data points displayed in a DataCurve you can use the following methods:
c.setRowRange(int startRow, int endRow) c.setFullRange()Also, you can hide/show a plot curve via:
c.setVisible(bool on)In case you need to get information about the data stored in the curve, you have at your disposal the functions below:
points = c.dataSize() for i in range (0, points): print i, "x = ", c.x(i), "y = ", c.y(i) print c.minXValue() print c.maxXValue() print c.minYValue() print c.maxYValue()
c
:
s = c.symbol() s.setSize(QtCore.QSize(7, 7))# or s.setSize(7) s.setBrush(QtGui.QBrush(Qt.darkYellow)) s.setPen(QtGui.QPen(Qt.blue, 3)) s.setStyle(PlotSymbol.Diamond) l.replot() # redraw the plot layer objectThe symbol styles available in QtiPlot are:
PlotSymbol.NoSymbol
PlotSymbol.Ellipse
PlotSymbol.Rect
PlotSymbol.Diamond
PlotSymbol.Triangle
PlotSymbol.DTriangle
PlotSymbol.UTriangle
PlotSymbol.LTriangle
PlotSymbol.RTriangle
PlotSymbol.Cross
PlotSymbol.XCross
PlotSymbol.HLine
PlotSymbol.VLine
PlotSymbol.Star1
PlotSymbol.Star2
PlotSymbol.Hexagon
g = newGraph().activeLayer() c = g.addFunction("cos(x)", 0, 10, 20) c.setSymbol(ImageSymbol("qtiplot/manual/html/icons/help.png"))Here's a short script showing how to draw a custom plot symbol and assign it to a curve:
pix = QtGui.QPixmap(QtCore.QSize(11, 11)) pix.fill(Qt.transparent) p = QtGui.QPainter(pix) r = QtCore.QRect(0, 0, 10, 10) p.drawEllipse(r) p.setPen(QtGui.QPen(Qt.red)) p.drawLine(5, 0, 5, 10) p.drawLine(0, 5, 10, 5) p.end() g = newGraph().activeLayer() c = g.addFunction("sin(x)", 0, 10, 20) c.setSymbol(ImageSymbol(pix))
f = l.addFunction("x*sin(x)", 0, 3*pi, points = 100) f.setTitle("x*sin(x)") f.setPen(Qt.green) f.setBrush(QtGui.QColor(0, 255, 0, 100)) l.addParametricFunction("cos(m)", "sin(m)", 0, 2*pi, points = 100, variableName = "m") l.addPolarFunction("t", "t", 0, 2*pi, points = 100, variableName = "t")It is possible to get a reference to an analytical function curve on the layer l using it's index, like shown below:
f = l.functionCurve(curveIndex)When dealing with analytical function curves, you can customize them using the following methods:
f.setRange(0, 2*pi) f.setVariable("t") f.setFormulas("sin(t)", "cos(t)") f.setFunctionType(FunctionCurve.Polar) # or c.setFunctionType(FunctionCurve.Parametric) f.loadData(1000, xLog10Scale = False) f.setFunctionType(FunctionCurve.Normal) f.setFormula("cos(x)") f.loadData()If you need to access the values and names of a function's parameters, you have at your disposal the following methods:
i = f.parametersCount() # the number of parameters in your function formula name = f.parameterName(index) # the name of the parameter of rang index as a QString p1 = f.parameterValue(index) # the value of the parameter of rang index as a double p2 = f.parameterValue(name) # the value of a parameter using its name stringThe abscissae range for which the function is calculated/displayed, can be obtained/modified via the methods below:
x1 = f.startRange() x2 = f.endRange() f.setRange(0.5, 15.2)
err1 = l.addErrorBars(c, Table *t, QString errColName, int type = 1, double width = 1, int capLength = 8, color = Qt.black, throughSymbol = True, minusSide = True, plusSide = True) err2 = l.addErrorBars(curveName, Table *t, QString errColName, int type = 1, double width = 1, int capLength = 8, color = Qt.black, throughSymbol = True, minusSide = True, plusSide = True)Each data curve, c, can have attached a list of error bars:
errors = c.errorBarsList()The properties of an error bar curve can be accesses, via the following methods:
err = c.errorBarsList()[0] for i in range(0, err.dataSize()): print err.errorValue(i) err.capLength() err.width() err.color() err.direction() err.xErrors() err.throughSymbol() err.plusSide() err.minusSide() c = err.masterCurve() # reference to the master curve to which the error bars curve is attached. err.detachFromMasterCurve() # equivalent to c.removeErrorBars(err)... and can be modified, via the following methods:
err.setCapLength(12) err.setWidth(3) err.setColor(Qt.red) err.setDirection(ErrorBarsCurve.Vertical) err.setXErrors(True) # equivalent to err.setDirection(ErrorBarsCurve.Horizontal) err.drawThroughSymbol(True) err.drawPlusSide(True) err.drawMinusSide(False) err.setMasterCurve(c)You can remove all error bars attached to a curve using:
c.clearErrorBars()
m = importImage("C:/poze/adi/PIC00074.jpg") g1 = plot(m, Layer.ColorMap) g2 = plot(m, Layer.Contour) g3 = plot(m, Layer.GrayScale)The plot functions above return a reference to the multilayer plot window. If you need a reference to the spectrogram object itself, you can get it as shown in the example below:
m = newMatrix("TestMatrix", 1000, 800) m.setFormula("x*y") m.calculate() g = plot(m, Layer.ColorMap) s = g.activeLayer().spectrogram(m) s.setColorBarWidth(20)It is possible to fine tune the plots created from a matrix:
m = newMatrix("TestMatrix", 1000, 800) m.setFormula("x*y") m.calculate() s = newGraph().activeLayer().plotSpectrogram(m, Layer.ColorMap) s.setContourLevels((20.0, 30.0, 60.0, 80.0)) s.setDefaultContourPen(QtGui.QPen(Qt.yellow)) # set global pen for the contour lines s.setLabelsWhiteOut(True) s.setLabelsColor(Qt.red) s.setLabelsFont(QtGui.QFont("Arial", 14)) s.setLabelsRotation(45) s.showColorScale(Layer.Top) s.setColorBarWidth(20)As you have seen earlier, you can set a global pen for the contour lines, using:
s.setDefaultContourPen(QtGui.QPen(Qt.yellow))You can also assign a specific pen for each contour line, using the function below:
s.setContourLinePen(index, QPen)or you can automatically set pen colors defined by the color map of the spectrogram:
s.setColorMapPen(bool on = True)You can also use any of the following functions:
s.setMatrix(Matrix *, bool useFormula = False) s.setUseMatrixFormula(bool useFormula = True)# calculate data to be drawn using matrix formula (if any) s.setLevelsNumber(int) s.showColorScale(int axis, bool on = True) s.setGrayScale() s.setDefaultColorMap() s.setCustomColorMap(LinearColorMap map) s.showContourLineLabels(bool show = True) # enable/disable contour line labels s.setLabelsOffset(int x, int y) # offset values for all labels in % of the text size s.updateData()
m = newMatrix("TestHistogram", 1000, 800) m.setFormula("x*y") m.calculate() g = newGraph().activeLayer() h = g.addHistogram(m) h.setBinning(10, 1, 90) # the bin size is set to 10, data range is set to [1, 90] h.loadData() # update the histogram g.replot() # update the display # print histogram values: for i in range (0, h.dataSize()): print i, "Bin start = ", h.x(i), "counts = ", h.y(i) # print statistic information: print "Standard deviation = ", h.standardDeviation() print "Mean = ", h.mean()You can also enable autobinning (a default number of ten bins will be used):
h.setAutoBinning()
g = newGraph().activeLayer() g.plotBox(table("Table1"), ["2", "3", "4"]) for i in range (0, g.numCurves()): box = g.boxCurve(i) if (box): box.setBrush(QtGui.QBrush(Qt.red, Qt.BDiagPattern)) s = PlotSymbol() s.setPen(QtGui.QPen(Qt.blue, 2)) s.setSize(QtCore.QSize(10, 10)) box.setSymbol(s) box.setMeanStyle(PlotSymbol.Cross) box.setBoxStyle(BoxCurve.WindBox) box.setBoxWidth(80) box.setWhiskersRange(BoxCurve.SD) # standard deviationThe following functions give access to the statistics information for the data series displayed with a box and whiskers plot:
s = box.statistics() # returns information as a string m = box.median() q = box.quantile(f) # f must be a fraction between 0 and 1For an exhaustive review of the methods giving access to the properties of a box plot, please consult the QtiPlot/Python API.
g = newGraph().activeLayer() pie = g.plotPie(table("Table1"), "2") pie.setRadius(70) pie.setViewAngle(40) pie.setThickness(20) pie.setStartAzimuth(45) pie.setLabelsEdgeDistance(50) pie.setCounterClockwise(True) pie.setBrushStyle(Qt.Dense3Pattern) pie.setFirstColor(3) pie.setPen(QtGui.QPen(Qt.red, 2)) pie.setLabelValuesFormat(True)For an exhaustive review of the methods giving access to the properties of a pie plot, please consult the QtiPlot/Python API.
g = newGraph().activeLayer() v = g.plotVectors(table("Table1"), ["1", "2", "3", "4"], Layer.VectXYAM) v.setVectorPen(Qt.red) v.fillArrowHead(False) v.setHeadAngle(15) v.setHeadLength(20) v.setPosition(VectorCurve.Middle)For an exhaustive review of the methods giving access to the properties of a vector curve, please consult the QtiPlot/Python API.
arrow = ArrowMarker() arrow.setStart(10.5, 12.5) arrow.setEnd(200, 400.51) arrow.setStyle(QtCore.Qt.DashLine) arrow.setColor(QtGui.QColor("red")) arrow.setWidth(1) arrow.drawStartArrow(False) arrow.drawEndArrow(True) arrow.setHeadLength(7) arrow.setHeadAngle(35) arrow.fillArrowHead(True) l = newGraph().activeLayer() arrow1 = l.addArrow(arrow) arrow.setStart(120.5, 320.5) arrow.setColor(QtGui.QColor("blue")) arrow2 = l.addArrow(arrow) l.remove(arrow1)
As you might notice from the sample code above, the addArrow
function
returns a reference to a new arrow object that can be used later on to modify this
new arrow or to delete it with the remove
function.
It is possible to modify the properties of all the lines/arrows in a plot layer, see the short example below:
g = graph("Graph1").activeLayer() lst = g.arrowsList() for i in range (0, g.numArrows()): lst[i].setColor(Qt.green) g.replot()
l = newGraph().activeLayer() image = l.addImage("C:/poze/adi/PIC00074.jpg") image.setCoordinates(200, 800, 800, 200) image.setFrameStyle(Frame.Shadow) image.setFrameColor(QtCore.Qt.green) image.setFrameWidth(3) l.replot()The
setCoordinates
function above can be used to set the geometry of the image using
scale coordinates. If you need to specify the image geometry in pixel coordinates, independently of
the plot axes values, you may use the following functions:
image.setOrigin(x, y) image.setSize(width, height) image.setRect(x, y, width, height) l.replot()You can remove an image using its reference:
l.remove(image)
l = newGraph().activeLayer() r = Rectangle(l) r.setSize(100, 100) r.setOrigin(100, 200) r.setBackgroundColor(QtCore.Qt.yellow) r.setFrameColor(QtCore.Qt.red) r.setFrameWidth(3) r.setFrameLineStyle(QtCore.Qt.DotLine) r.setBrush(QtGui.QBrush(QtCore.Qt.green, QtCore.Qt.FDiagPattern)) r1 = l.add(r)You can remove a rectangle using its reference:
r2 = l.add(r) r2.setOrigin(200, 200) l.remove(r1)
l = newGraph().activeLayer() e = Ellipse(l) e.setSize(100, 100) e.setOrigin(100, 200) e.setBackgroundColor(QtCore.Qt.yellow) e.setFrameColor(QtCore.Qt.red) e.setFrameWidth(0.8) e.setFrameLineStyle(QtCore.Qt.DotLine) e.setBrush(QtGui.QBrush(QtCore.Qt.green, QtCore.Qt.FDiagPattern)) l.add(e)
l.export(fileName)This function uses some default parameters for the properties of the image. If you need more control over the exported images you can use one of the following specialized functions:
l.exportVector(fileName, dpi = 96, color = True, size = QtCore.QSizeF(), unit = Frame.Pixel, fontsFactor = 1.0) l.exportImage(fileName, quality = 100, transparent = False, dpi = 0, size = QtCore.QSizeF(), unit = Frame.Pixel, fontsFactor = 1.0, compression = 0) l.exportTex(fileName, color = True, escapeStrings = True, fontSizes = True, size = QtCore.QSizeF(), unit = Frame.Pixel, fontsFactor = 1.0)
The function exportVector
can export the plot/layer to the following vector formats:
.eps, .ps, .pdf.
The function exportImage
can be used if you need to export to
one of the Qt supported raster image formats (.bmp, .png, .jpg, etc...). The transparent
option can only be used in conjunction with the file formats supporting transprency: .png and .tif (.tiff).
The quality
parameter influences the size of the output file. The higher this value (maximum is 100),
the higher the quality of the image, but the larger the size of the resulting files.
The dpi
parameter represents the export resolution in pixels per inch (the default is screen resolution),
size
is the printed size of the image (the default is the size on screen) and
unit
is the length unit used to express the custom size
and can take one of the following values:
Inch
Millimeter
Centimeter
Point: 1/72th of an inch
Pixel
fontsFactor
parameter represents a scaling factor
for the font sizes of all texts in the plot (the default is 1.0, meaning no scaling).
If you set this parameter to 0, the program will automatically try to calculate
a scale factor.
The compression
parameter can be 0 (no compression) or 1 (LZW) and is only effectif for .tif/.tiff images.
It is neglected for all other raster image formats.
The function exportTex
can be used if you need to export to
a TeX file. The escapeStrings
parameter enables/disables the escaping of
special TeX characters like: $, {, }, ^, etc...
If True
, the fontSizes
parameter triggers the export of the original
font sizes in the plot layer.
Otherwise all exported text strings will use the font size specified in the preamble of
the TeX document.
All the export functions rely on the file name suffix in order to choose the image format.
g = newGraph("Test", 4, 2, 2) g.setLayerCanvasSize(400, 300) g.arrangeLayers(False, True)The
arrangeLayers()
function takes two parameters. The first one specifies
if the layers should be arranged automatically, using a best-layout algorithm, or if the
numbers of rows and columns is fixed by the user. If the value of the second parameter is
True
, the size of the canvas is fixed by the user and the plot window
will be enlarged or shrunken, according to the user settings. Otherwise the size of the plot
window will be kept and the canvas area of each layer will be automatically adapted to fit this size.
Here's how you can modify the graph created in the previous example, in order to display a row of three
layers, while keeping the size of the plot window unchanged:
g.setNumLayers(3) g.setRows(1) g.setCols(3) g.arrangeLayers(False, False)By default, the space between two neighboring layers as well as the distance between the layers and the borders of the plot window is set to five pixels. You can change the spacing between the layers and the margins using the following functions:
g.setSpacing (x, y) g.setMargins (left, right, top, bottom)Another aspect of the layout management is the alignment of the layers. There are three alignment flags that you can use for the horizontal alignment (HCenter, Left, Right) and another three for the vertical alignment (VCenter, Top, Bottom) of the layers. The following code line aligns the layers with the right edge of the window and centers them vertically in the available space:
g.setAlignement(Graph.Right, Graph.VCenter)The alignment of the layers can be done with respect to the drawing area between the axes (Graph.AlignCanvases) or with respect to the whole layer widget (Graph.AlignLayers) and you can specify the alignment policy to use via the following method:
g.setAlignPolicy(Graph.AlignCanvases)A very often needed layout is the one with shared layer axes having linked abscissae (modifying the x scale for one layer will automatically adjust the scales for all plot layers). Here's how you can simply create such a 2x2 layers grid, with only a few lines of code:
g = newGraph("", 4, 2, 2) g.setSpacing(0, 0) g.setAlignPolicy(Graph.AlignCanvases) g.setCommonLayerAxes() g.arrangeLayers() g.linkXLayerAxes(True)All the examples above suppose that the layers are arranged on a grid, but of course you can add layers at any position in the plot window. In the examples below the x, y coordinates, in pixels, refer to the position of the top-left corner of the layer. The origin of the coordinates system coincides with the top-left corner of the plot window, the y coordinate increasing towards the bottom of the window. If the width and height of the layer are not specified they will be set to the default values. The last argument specifies if the default preferences, specified via the Preferences dialog, will be used to customize the new layer (default value is
False
):
g = newGraph() l1 = g.addLayer() l2 = g.addLayer(215, 20) l3 = g.addLayer(10, 20, 200, 200) l4 = g.addLayer(10, 20, 200, 200, True)You can remove a plot layer using:
l = g.layer(num) g.removeLayer(l) g.removeActiveLayer()As you have already seen, in a plot window the active layer is, by default, the last layer added to the plot, but you can change it programatically:
l = g.layer(num) g.setActiveLayer(l)In case you need to perform a repetitive task on all the layers in a plot window, you need to use a for loop and of course you need to know the number of layers existing on the plot. Here's a small example showing how to custom the titles of all the layers in the plot window:
g = graph("Graph1") layers = g.numLayers() for i in range (1, layers+1): l = g.layer(i) l.setTitle("Layer"+QtCore.QString.number(i)) l.setTitleColor(QtGui.QColor("red")) l.setTitleFont(QtGui.QFont("Arial", 14, QtGui.QFont.Bold, True)) l.setTitleAlignment(QtCore.Qt.AlignLeft)Finally, sometimes it might be useful to be able to swap two layers. This can be done with the help of the following function:
g.swapLayers(layerNum1, layerNum2)
g = waterfallPlot(table("Table1"), (2, 3, 4)) l = g.activeLayer() l.setWaterfallOffset(50, 20)# x/y offsets as % of the layer drawing area width/height l.setWaterfallSideLines(True) # draw side lines for all the data curves l.setWaterfallFillColor(Qt.lightGray) g.reverseWaterfallOrder() # reverse the order of the displayed curves
x
for the the abscissae values and y
for the ordinates:
g = plot3D("sin(x*y)", -10.0, 10.0, -10.0, 10.0, -2.0, 2.0)For the parametric surfaces the only parameters allowed are the latitude and the longitude:
u
and v
. Here's, for example,
how you can plot a sphere:
g = plot3D("cos(u)*cos(v)", "sin(u)*cos(v)", "sin(v)", -3.14, 3.14, -2, 2)You can also create 3D height maps using data from matrices and, of course, you can plot table columns:
g = plot3D(matrix("Matrix1"), style = 5) g = plot3D(table("Table1"), "3", style)In the case of 3D plots created from matrix data sources the
style
parameter can take
any integer value from 1 to 5, with the following signification:
Wireframe style
Hidden Line style
Color filled polygons without edges
Color filled polygons with separately colored edges
Scattered points (the default style)
style
parameter can take
any integer value from 0 to 3 or the equivalent style values from the following list:
Graph3D.Scatter
Graph3D.Trajectory
Graph3D.Bars
Graph3D.Ribbon
g = newPlot3D("test3D") g.setTitle("My 3D Plot", QtGui.QColor("blue"), QtGui.QFont("Arial",14)) g.setResolution(2) g.setFunction("sin(x*y)", -10.0, 10.0, -10.0, 10.0, -2.0, 2.0) #or g.setData(table("Table1"), "3") #or g.setMatrix(matrix("Matrix1"))Once a plot is created, you can modify the scales and set the data range to display, using, for example:
g.setScales(-1.0, 1.0, -10.0, 11.0, -2.0, 3.0)
g.setRotation(45, 15, 35)The following function allows you to shift the plot along the world X, Y and Z axes, respectively:
g.setShift(3.0, 7.0, -4.0)You can also zoom in/out the entire plot as a whole, or you can zoom along a particular axis:
g.setZoom(10) g.setScale(0.1, 0.05, 0.3)Also, you can automatically detect the zoom values that fit best with the size of the plot window:
g.findBestLayout()You can enable/disable the perspective view mode or animate the view using:
g.setOrthogonal(False) g.animate(True)
g.setPolygonStyle() g.setFilledMeshStyle() g.showLegend(True) g.setHiddenLineStyle() g.setWireframeStyle() g.setAntialiasing(True) g.setMeshLineWidth(0.7)For scatter plots using points you can specify the radius of the points and their shape: circles if
smooth
is True, rectangles otherwise.
g.setDotOptions(10, smooth = True) g.setDotStyle()Other symbols available for scatter plots are: bars
g.setBarRadius(0.01) g.setBarLines(False) g.setFilledBars(True) g.setBarStyle()cones
g.setConeOptions(radius, quality) g.setConeStyle()and crosses (surrounded by a box frame, if
boxed
is set to True):
g.setCrossOptions(radius, width, smooth, boxed) g.setCrossStyle()
g.showFloorProjection() g.showFloorIsolines() g.setEmptyFloor()
g.setBoxed() g.setFramed() g.setNoAxes()If the axes are enabled, you can set their legends and the distance between the legend and the axes via:
g.setXAxisLabel("X axis legend") g.setYAxisLabel("Y axis legend") g.setZAxisLabel("Z axis legend") g.setLabelsDistance(30)It is possible to set the numerical format and precision of the axes using the function below:
g.setAxisNumericFormat(axis, format, precision)where the first parameter is the index of the axis: 0 for X, 1 for Y and 2 for Z, the second one is the numerical format:
Graph3D.Default: decimal or scientific, depending which is most compact
Graph3D.Decimal: 10000.0
Graph3D.Scientific: 1e4
Graph3D.Engineering: 10k
g.setXAxisNumericFormat(1, 3) g.setYAxisNumericFormat(1, 3) g.setZAxisNumericFormat(1, 3)Also, you can fix the length of the major and minor ticks of an axis:
g.setXAxisTickLength(2.5, 1.5) g.setYAxisTickLength(2.5, 1.5) g.setZAxisTickLength(2.5, 1.5)
g.setLeftGrid(True) g.setRightGrid() g.setCeilGrid() g.setFloorGrid() g.setFrontGrid() g.setBackGrid(False)
g.setDataColors(QtCore.Qt.black, QtCore.Qt.green) g.update()Of course, you can define more complex color maps, using LinearColorMapobjects:
map = LinearColorMap(QtCore.Qt.yellow, QtCore.Qt.blue) map.setMode(LinearColorMap.FixedColors) # default mode is LinearColorMap.ScaledColors map.addColorStop(0.2, QtCore.Qt.magenta) map.addColorStop(0.7, QtCore.Qt.cyan) g.setDataColorMap(map) g.update()Also, you can use predefined color maps stored in .map files. A .map file consists of a of 255 lines, each line defining a color coded as RGB values. A set of predefined color map files can be downloaded from QtiPlot web site, in the "Miscellaneous" section.
g.setDataColorMap(fileName) g.update()The colors of all the other plot elements can be customized as shown below. Don't forget to update the plot in order to display the new colors:
g.setMeshColor(QtGui.QColor("blue")) g.setAxesColor(QtGui.QColor("green")) g.setNumbersColor(QtGui.QColor("black")) g.setLabelsColor(QtGui.QColor("darkRed")) g.setBackgroundColor(QtGui.QColor("lightYellow")) g.setGridColor(QtGui.QColor("grey")) g.setDataColors(QtGui.QColor("red"), QtGui.QColor("orange")) g.setOpacity(0.75) g.update()
g.export(fileName)This function uses some default export options. If you want to customize the exported image, you should use the following function in order to export to raster image formats:
g.exportImage(fileName, int quality = 100, bool transparent = False, dpi = 0, size = QSizeF(), unit = Frame.Pixel, fontsFactor = 1.0, compression = 0)where
quality
is a compression factor: the larger its value, the better the quality of the
exported image, but also the larger the file size.
The dpi
parameter represents the export resolution in pixels per inch (the default is screen resolution),
size
is the printed size of the image (the default is the size on screen) and
unit
is the length unit used to express the custom size
and can take one of the following values:
Inch
Millimeter
Centimeter
Point: 1/72th of an inch
Pixel
fontsFactor
parameter represents a scaling factor
for the font sizes of all texts in the plot (the default is 1.0, meaning no scaling).
If you set this parameter to 0, the program will automatically try to calculate
a scale factor. The compression
parameter can be 0 (no compression) or 1 (LZW) and is only effectif for .tif/.tiff images.
It is neglected for all other raster image formats.
3D plots can be exported to any of the following vector formats: .eps, .ps, .pdf, .pgf and .svg, using the function below:
g.exportVector(fileName, textMode = 0, sortMode = 1, size = QSizeF(), unit = Frame.Pixel, fontsFactor = 1.0)where
textMode
is an integer value, specifying how texts are handled. It can take
one of the following values:
All text will be converted to bitmap images (default).
Text output in the native output format.
Text output in additional LaTeX file as an overlay.
sortMode
parameter is also an integer value and can take one of the following values:
No sorting at all.
A simple, quick sort algorithm (default).
BSP sort: best algorithm, but slow.
op = LogisticFit(graph("Graph1").activeLayer().curve(0), 15.2, 30.9) op = FFTFilter(graph("Graph1").activeLayer(), "Table1_2", 1.5, 3.9) op = LinearFit(table("Table1"), "colX", "colY", 10, 100)In the first example the data source is a curve Table1_2, plotted in the active layer of the graph Graph1and the abscissae range is chosen between 1.5 and 3.9. In the second example the data source is a table Table1. The abscissae of the data set are stored in the column called colXand the ordinates in the column colY. The data range is chosen between the 10th row and the row with the index 100. If you don't specify the row range, by default the whole table will be used. Not all operations support curves as data sources, like for example: convolution/deconvolution and correlation. For these operations only table columns can be used as data sources for the moment.
Once you have initialized an operation, you can still change its input data via the following functions:
op.setDataFromCurve(graph("Graph2").activeLayer().curve(1), 10.5, 20.1) op.setDataFromCurve("Table1_energy", 10.5, 20.1, graph("Graph2").activeLayer()) op.setDataFromTable(table("Table1"), "colX", "colY", 10, 100)You don't have to specify a plot layer in the setDataFromCurve() function, if the analysis operation has already been initialized by specifying a curve on an existing graph and you just want to treat another curve from the same plot layer.
Also, when performing analysis tasks via Python scripts, there are several utility functions that can be called for all operations. For example you can disable any graphical output from an operation or you can redirect the output to the plot layer of your choice:
op.enableGraphicsDisplay(False) op.enableGraphicsDisplay(True, graph("Graph2").activeLayer())Let's assume that you need to perform a specific operation
op
,
which analyzes your data and at the end, displays a result curve.
For this kind of operations, you can customize the number of points in the resulting curve
and its color:
op.setOutputPoints(int) op.setColor(int) op.setColor("green")Colors can be specified by their names or as integer values, from 0 to 23, each integer corresponding to a predefined color: 0 - "black", 1 - "red", 2 - "green", 3 - "blue", 4 - "cyan", 5 - "magenta", 6 - "yellow", 7 - "darkYellow", 8 - "navy", 9 - "purple", etc ...
Most of the time, a new table is also created as a result of a data analysis operation. This table stores the data displayed by the result curve and is hidden by default, but you can interact with it via the following function:
t = op.resultTable()After the initialization of an analysis operation, which consists of setting the data source, the data range and some other properties, like color, number of points, etc..., you can execute it via a call to its run() function:
op.run()For data fitting operations, there's an alias for the run() function which is: fit().
conv = Convolution(table("Table1"), "B", "C") conv.setColor("green") conv.run()The deconvolution and the correlation of two data sets can be done using a similar syntax:
dec = Deconvolution(table("Table1"), "B", "C") dec.run() cor = Correlation(table("Table1"), "B", "C", 10, 200) cor.setColor("green") cor.run()
diff = Differentiation(graph("Graph1").activeLayer().curve(0), 2, 10) diff.run()The result of these code sequence would be a new plot window displaying the derivative of the initial curve. The numerical derivative is calculated using a five terms formula.
fft = FFT(graph("Graph1").activeLayer().curve(0)) fft.normalizeAmplitudes(False) fft.shiftFrequencies(False) fft.setSampling(0.1) fft.run()By default the calculated amplitudes are normalized and the corresponding frequencies are shifted in order to obtain a centered x-scale. If we want to recover the initial curve with the help of the inverse transformation, we mustn't modify the amplitudes and the frequencies. Also the sampling parameter must be set to the inverse of the time period, that is 10. Here's how we can perform the inverse FFT, using the "FFT1" table, in order to recover the original curve:
ifft = FFT(table("FFT1"), "Real", "Imaginary") ifft.setInverseFFT() ifft.normalizeAmplitudes(False) ifft.shiftFrequencies(False) ifft.setSampling(10) ifft.run()You can also perform 2D fast Fourrier transforms on matrices. The FFT routine takes in this case the following parameters: rm- specifies the real part input matrix, im- specifies the imaginary part input matrix, inverse- specifies the direction of the FFT, DCShift- if this is true, the DC component will be put in the center of the result matrix, otherwise, the DC component will locate at four corners of the result matrix, norm- specifies whether or not to normalize the amplitudes to 1, outputPower2Sizes- forces output matrices whose sizes are integer powers of 2 (zero padding is used to initialize the missing cells)
fft = FFT(Matrix *rm, Matrix *im = NULL, bool inverse = False, bool DCShift = True, bool norm = False, bool outputPower2Sizes = True)Here's how you can perform the 2D FFT of a matrix called "Matrix1", and the inverse FFT in order to recover the original image:
from qti import * m = matrix("Matrix1") m.setViewType(Matrix.ImageView) # make sure the matrix is displayed as image fft = FFT(m) fft.run() fft.amplitudesMatrix().resize(500, 400) rMatrix = fft.realOutputMatrix() rMatrix.hide() iMatrix = fft.imaginaryOutputMatrix() iMatrix.hide() ifft = FFT(rMatrix, iMatrix, True) ifft.run() ifft.realOutputMatrix().hide() ifft.imaginaryOutputMatrix().hide()
filter = FFTFilter(graph("Graph1").activeLayer().curve(0), FFTFilter.HighPass) filter.setCutoff(1) filter.run()Here's how you can cut all the frequencies lower than 1.5 Hz and higher than 3.5 Hz. In the following example the continuous component of the signal is also removed:
filter.setFilterType(FFTFilter.BandPass) filter.enableOffset(False) filter.setBand(1.5, 3.5) filter.run()Other types of FFT filters available in QtiPlot are: low pass (
FFTFilter.LowPass
)
and band block (FFTFilter.BandBlock
).
f = GaussFit(graph("Graph1").activeLayer().curve(0)) f.guessInitialValues() f.fit()This creates a new GaussFit object on the curve, lets it guess the start parameters and does the fit. The following fit types are supported:
LinearFit(curve)
PolynomialFit(curve, degree=2, legend=False)
ExponentialFit(curve, growth=False)
TwoExpFit(curve)
ThreeExpFit(curve)
GaussFit(curve)
GaussAmpFit(curve)
LorentzFit(curve)
LogisticFit(curve)
SigmoidalFit(curve)
NonLinearFit(curve)
f = NonLinearFit(layer, curve) f.setFormula(formula_string) f.save(fileName)
PluginFit(curve)
f = PluginFit(curve) f.load(pluginName)
f = LinearFit(graph("Graph1").activeLayer().curve(0), 2, 7) f.fit()You can also restrict the search range for any of the fit parameters:
f = NonLinearFit(graph("Graph1").activeLayer().curve(0)) f.setFormula("a0+a1*x+a2*x*x") f.setParameterRange(parameterIndex, start, end)All the settings of a non-linear fit can be saved to an XML file and restored later one, using this file, for a faster editing process. Here's for example how you can save the above fit function:
f.save("/fit_models/poly_fit.txt")and how you can use this file during another fitting session, later on:
f = NonLinearFit(graph("Graph1").activeLayer(), "Table1_2") f.load("/fit_models/poly_fit.txt") f.fit()If your script relies on a specific numbering of the fit parameters use setParameters() before setting the formula and switch of automatic detection of the fit parameters when the fit formula is set:
f.setParameters("a2","a0","a1") f.setFormula("a0+a1*x+a2*x*x",0)
After creating the Fit object and before calling its fit() method, you can set a number of parameters that influence the fit:
f.setDataFromTable(table("Table4"), "w", "energy", 10, 200, True) change data source (last parameter enables/disables data sorting) f.setDataFromCurve(curve) change data source f.setDataFromCurve(curveTitle, graph) change data source f.setDataFromCurve(curve, from, to) change data source f.setDataFromCurve(curveTitle, from, to, graph) change data source f.setInterval(from, to) change data range f.setInitialValue(number, value) f.setInitialValues(value1, ...) f.guessInitialValues() f.setAlgorithm(algo) # algo = Fit.ScaledLevenbergMarquardt, Fit.UnscaledLevenbergMarquardt, Fit.NelderMeadSimplex f.setWeightingData(method, colname) # method = Fit.NoWeighting, Fit.Instrumental, Fit.Statistical, Fit.Dataset, Fit.Direct f.setTolerance(tolerance) f.setOutputPrecision(precision) f.setMaximumIterations(number) f.scaleErrors(yes = True) f.setColor("green") change the color of the result fit curve to green (default color is red)After you've called fit(), you have a number of possibilities for extracting the results:
f.results() f.errors() f.residuals() f.dataSize() f.numParameters() f.parametersTable("params") f.covarianceMatrix("cov")There are a number of statistical functions allowing you to test the goodness of the fit:
f.chiSquare() f.rSquare() f.adjustedRSquare() f.rmse() # Root Mean Squared Error f.rss() # Residual Sum of SquaresAlso you can display the confidence and the prediction limits for the fit, using a custom confidence level:
f.showPredictionLimits(0.95) f.showConfidenceLimits(0.95)Confidence limits for individual fit parameters can be calculated using:
f.lcl(parameterIndex, confidenceLevel) f.ucl(parameterIndex, confidenceLevel)where
parameterIndex
is a value between zero and f.numParameters() - 1.
It is important to know that QtiPlot can generate an analytical formula for the resulting fit curve or a normal plot curve with data stored in a hidden table. You can choose either of these two output options, before calling the fit() instruction, using:
f.generateFunction(True, points=100)If the first parameter of the above function is set to True, QtiPlot will generate an analytical function curve. If the
points
parameter
is not specified, by default the function will be estimated over 100 points.
You can get the analytical formula of the fit curve via a call to resultFormula():
formula = f.resultFormula() print(formula)If the first parameter of generateFunction() is set to False, QtiPlot will create a hidden data table containing the same number of points as the data set/curve to be fitted (same abscissae). You can interact with this table and extract the data points of the result fit curve using:
t = f.resultTable()
integral = Integration(graph("Graph1").activeLayer().curve(0), 2, 10) integral.run() result = integral.area()The script bellow shows how to perform an integration on a data set from a table:
i = Integration(table("Table1"), "Table_1", "Table_2", 3, 20, True)# sorted data range from row 3 to 20 i.enableGraphicsDisplay(False) i.run() result = i.area()
As you can see from the above examples, the numerical value of the integral can be obtained
via the area()
function.
interpolation = Interpolation(graph("Graph1").activeLayer().curve(0), 2, 10, Interpolation.Linear) interpolation.setOutputPoints(10000) interpolation.setColor("green") interpolation.run()The simplest interpolation method is the linear method. There are two other methods available:
Interpolation.Akima
and Interpolation.Cubic
.
You can choose the interpolation method using:
interpolation.setMethod(Interpolation.Akima)
smooth = SmoothFilter(graph("Graph1").activeLayer().curve(0), SmoothFilter.Average) smooth.setSmoothPoints(10) smooth.run()The default smoothing method is the mowing window average. Other smoothing methods are the
SmoothFilter.FFT
, SmoothFilter.Lowess
and SmoothFilter.SavitzkyGolay
. Here's an example
of how to use the last two methods:
smooth.setMethod(SmoothFilter.Lowess) smooth.setLowessParameter(0.2, 2) smooth.run()
smooth.setSmoothPoints(5,5) smooth.setMethod(SmoothFilter.SavitzkyGolay) smooth.setPolynomOrder(9) smooth.run()
stats = Statistics("Table1_2") stats.run() print stats.mean() print stats.variance() print stats.standardDeviation() print stats.standardError()
test.showResultsLog(False) # disable the logging of the results test.showDescriptiveStatistics(False) # disable the display of the descriptive statistics results test.run() print test.statistic() print test.pValue() print test.logInfo() t = test.resultTable("MyResultTable") # Returns a pointer to the table created to display the results (the table name is optional)
test = tTest(15.2, 0.05, "Table1_2") # One sample test, test mean = 15.2, significance level = 0.05 test.run() test.setTestValue(15.0) test.setSignificanceLevel(0.5) test.setTail(tTest.Left) # or tTest.Right, or tTest.Both (default value) test.run() print test.t() # same as test.statistic() print test.dof() # degrees of freedom print test.power(0.5) print test.power(0.5, 50) # alternative sample size = 50 print test.pValue() print test.lcl(90) # lower confidence limit for mean print test.ucl(90) # upper confidence limit for mean test = tTest(15.2, 0.05, "Table1_1", "Table1_2", True) # Two sample paired test print test.logInfo() test = tTest(15.2, 0.05, "Table1_1", "Table1_2") # Two sample independent test test.run() test.setSample1("Table2_1") test.setSample2("Table3_2", True) # Two sample paired test test.run()
test = ChiSquareTest(88.2, 0.05, "Table1_2") # Test variance = 88.2, significance level = 0.05 test.run() print test.chiSquare() # same as test.statistic() print test.pValue() print test.logInfo()
test = ShapiroWilkTest("Table3_1") test.setSignificanceLevel(0.1) test.run() print test.w() # same as test.statistic() print test.pValue() print test.logInfo()
test = Anova() test.setSignificanceLevel(0.1) # default level is 0.05 test.addSample("Table1_1"); test.addSample("Table1_2"); test.addSample("Table1_3"); test.run() print test.fStat() # F statistic = ssm/sse (same as test.statistic()) print test.pValue() print test.ssm() # "between-group" sum of squares print test.sse() # "within-group" sum of squares print test.sst() # total sum of squares test.showDescriptiveStatistics(False) print test.logInfo()
test = Anova(True) test.addSample("Table1_1", 1, 1) # Level factor A = 1, level factor B = 1 test.addSample("Table1_2", 1, 2) # Level factor A = 1, level factor B = 2 test.addSample("Table1_3", 2, 1) # Level factor A = 2, level factor B = 1 test.addSample("Table1_4", 2, 2) # Level factor A = 2, level factor B = 2 test.setAnovaTwoWayModel(2) # Fixed model = 0, Random model = 1, Mixed model = 2 test.run() print test.fStatA() # F statistic for factor A print test.fStatB() # F statistic for factor B print test.fStatAB() # F statistic for the interaction print test.pValueA() # P value for factor A print test.pValueB() # P value for factor B print test.pValueAB() # P value for the interaction print test.ssa() # sum of squares for factor A print test.ssb() # sum of squares for factor B print test.ssab() # sum of squares for the interaction print test.msa() # mean square value for factor A print test.msb() # mean square value for factor B print test.msab() # mean square value for the interaction print test.logInfo()
The following functions are available when dealing with multi-tab notes:
setAutoexec(on = True) text() setText(text) exportPDF(fileName) saveAs(fileName) importASCII(fileName) showLineNumbers(on = True) setFont(QFont f) setTabStopWidth(int length) tabs() addTab() removeTab(tabIndex) renameTab(tabIndex, title) e = editor(int index) e = currentEditor()
# Pop-up a file dialog allowing to chose the working folder: dirPath = QtGui.QFileDialog.getExistingDirectory(qti.app, "Choose Working Folder", "/test/") # Create a folder object using Qt's QDir class: folder = QtCore.QDir(dirPath) # Pop-up a text input dialog allowing to chose the file naming pattern: namePattern = QtGui.QInputDialog.getText(qti.app, "Enter Pattern", "Text: ", QtGui.QLineEdit.Normal, "disper1") # Get the list of file names in the working directory containing the above pattern: fileNames = folder.entryList (QtCore.QStringList ("*_" + namePattern[0] + "*.dat")) # Import each file into a new project table: for i in range (0, lst.count()): t = newTable() t.importASCII(dirPath + fileNames[i], " ", 0, False, True, True)For a detailed description of all the dialogs and utility classes provided by Qt/PyQt please take a look at the PyQt documentation.
uic
module.
As an example, suppose that we have created a test dialog containing an input QDoubleSpinBox called "valueBox" and a QPushButton called "okButton". On pressing this button, we would like to create a new table displaying the input value in its first cell. We have saved this dialog to a file called "myDialog.ui". A minimalistic approach is shown in the small script below:
from PyQt4 import uic def createTable(): t = newTable() t.setCell(1, 1, ui.valueBox.value()) ui = uic.loadUi("myDialog.ui") ui.connect(ui.okButton, QtCore.SIGNAL("clicked()"), createTable) ui.show()For more details about how to use .ui files in your Python scripts please read the PyQt4 documentation.
import urllib, re, sys # Pop-up a file dialog allowing to chose a destination folder: dirPath = QtGui.QFileDialog.getExistingDirectory(qti.app, "Choose Destination Folder") saveout = sys.stdout # create a log file in the destination folder fsock = open(dirPath + "/" + "results.txt", "w") sys.stdout = fsock # on Unix systems you can redirect the output directly to a console by uncommenting the line below: #sys.stdout = sys.__stdout__ # make sure that the decimal separator is the dot character qti.app.setLocale(QtCore.QLocale.c()) host = "http://www.itl.nist.gov/div898/strd/nls/data/LINKS/DATA/" url = urllib.urlopen(host) url_string = url.read() p = re.compile( '\w{,}.dat">' ) iterator = p.finditer( url_string ) for m in iterator: name = (m.group()).replace("\">", "") if (name == "Nelson.dat"): continue url = host + name print "\nRetrieving file: " + url path = dirPath + "/" + name urllib.urlretrieve( url, path ) # retrieve .dat file to specified location file = QtCore.QFile(path) if file.open(QtCore.QIODevice.ReadOnly): ts = QtCore.QTextStream(file) name = name.replace(".dat", "") changeFolder(addFolder(name)) #create a new folder and move to it formula = "" parameters = 0 initValues = list() certifiedValues = list() standardDevValues = list() xLabel = "X" yLabel = "Y" while (ts.atEnd() == False): s = ts.readLine().simplified() if (s.contains("(y = ")): lst = s.split("=") yLabel = lst[1].remove(")") if (s.contains("(x = ")): lst = s.split("=") xLabel = lst[1].remove(")") if (s.contains("Model:")): s = ts.readLine().simplified() lst = s.split(QtCore.QRegExp("\\s")) s = lst[0] parameters = s.toInt()[0] ts.readLine() if (name == "Roszman1"): ts.readLine() formula = ts.readLine().simplified() else: formula = (ts.readLine() + ts.readLine() + ts.readLine()).simplified() formula.remove("+ e").remove("y =").replace("[", "(").replace("]", ")") formula.replace("**", "^").replace("arctan", "atan") if (s.contains("Starting")): ts.readLine() ts.readLine() for i in range (1, parameters + 1): s = ts.readLine().simplified() lst = s.split(" = ") s = lst[1].simplified() lst = s.split(QtCore.QRegExp("\\s")) initValues.append(lst[1]) certifiedValues.append(lst[2]) standardDevValues.append(lst[3]) if (s.contains("Data: y")): row = 0 t = newTable(name, 300, 2) t.setColName(1, "y") t.setColumnRole(1, Table.Y) t.setColName(2, "x") t.setColumnRole(2, Table.X) while (ts.atEnd() == False): row = row + 1 s = ts.readLine().simplified() lst = s.split(QtCore.QRegExp("\\s")) t.setText(1, row, lst[0]) t.setText(2, row, lst[1]) g = plot(t, t.colName(1), Layer.Scatter).activeLayer() g.setTitle("Data set: " + name + ".dat") g.setAxisTitle(Layer.Bottom, xLabel) g.setAxisTitle(Layer.Left, yLabel) f = NonLinearFit(g, name + "_" + t.colName(1)) if (f.setFormula(formula) == False) : file.close() changeFolder(rootFolder()) continue f.scaleErrors() for i in range (0, parameters): f.setInitialValue(i, initValues[i].toDouble()[0]) f.fit() g.removeLegend() f.showLegend() print "QtiPlot Results:\n" + f.legendInfo() print "\nCertified Values:" paramNames = f.parameterNames() for i in range (0, parameters): print '%s = %s +/- %s' % (paramNames[i], certifiedValues[i], standardDevValues[i]) print "\nDifference with QtiPlot results:" results = f.results() for i in range (0, parameters): diff = fabs(results[i] - certifiedValues[i].toDouble()[0]) print 'db%d = %6g' % (i+1, diff) file.close() changeFolder(rootFolder()) newNote("ResultsLog").importASCII(dirPath + "/" + "results.txt") saveProjectAs(dirPath + "/" + "StRD_NIST.qti") sys.stdout = saveout fsock.close()
In recent versions the scope rules were changed to match standard Python:
x
in the module namespace.
Previously, "global" referred to QtiPlot's global variables, and module-level variables were inaccessible
from inside a function, unless marked global.globals
:globals.myvar = 5 print globals.myvar
globals
is shared among all modules.If a script has any "global" declaration outside of a function, QtiPlot uses the old scope rules. Existing scripts should keep working, but for best results, update your scripts:
x
is used only within one script, delete any "global x"
that is outside of a function.global x x = 5to
globals.x = 5and replace all references to
x
with globals.x