[Paraview] Bug with PV 5.2 with python max / min

[Cory Quammen]

Hi Guillaume,

Thanks for the report.

As a workaround, you can still use the builtin min() function with

from __builtin__ import min as min, max as max

HTH,
Cory

On Thu, Nov 17, 2016 at 6:22 AM, Guillaume Jacquenot
<guillaume.jacquenot at gmail.com> wrote:
> Dear all,
>
> I have just tested the new paraview 5.2 with a python script.
>
> With versions 4.4.0 and 5.1.2, this script worked fine.
>
> In this script, I have a ProgrammableSource where I compute the maximum
> values of two scalars with max function.
>
> The code looks like this in the Script of the ProgrammableSource
>
> maxValue = max(1,2)
>
> This instruction creates an error: instead of using built-in max function,
> ParaView5.2 uses a max function defined with vtk and numpy:
>
> ParaView-5.2.0-Qt4-OpenGL2-Windows-64bit\bin\Lib\site-packages\vtk\numpy_interface\algorithms.py
> line 315
>
> And apparently, it does not work (whereas in 4.4.0 and 5.1.2 it worked,
> maybe these versions did not use this function).
>
> For the time being, I have created a dirty workaround where I have defined
> new min / max functions
>
>     fmin = lambda x,y:x if x<y else y
>     fmax = lambda x,y:x if x>y else y
>
>
>
> Below are the message error and a python script that reproduces the bug
>
>
> Traceback (most recent call last):
>   File "<string>", line 20, in <module>
>   File "<string>", line 326, in RequestData
>   File
> "D:\ParaView-5.2.0-Qt4-OpenGL2-Windows-64bit\bin\lib\site-packages\vtk\numpy_interface\algorithms.py",
> line 354, in max
>     return _global_func(MaxImpl(), array, axis, controller)
>   File
> "D:\ParaView-5.2.0-Qt4-OpenGL2-Windows-64bit\bin\lib\site-packages\vtk\numpy_interface\algorithms.py",
> line 182, in _global_func
>     res = impl.op()(array, axis)
>   File
> "D:\ParaView-5.2.0-Qt4-OpenGL2-Windows-64bit\bin\lib\site-packages\vtk\numpy_interface\internal_algorithms.py",
> line 363, in max
>     ans = numpy.max(narray, axis)
>   File
> "D:\ParaView-5.2.0-Qt4-OpenGL2-Windows-64bit\bin\lib\site-packages\numpy\core\fromnumeric.py",
> line 2125, in amax
>     out=out, keepdims=keepdims)
>   File
> "D:\ParaView-5.2.0-Qt4-OpenGL2-Windows-64bit\bin\lib\site-packages\numpy\core\_methods.py",
> line 17, in _amax
>     out=out, keepdims=keepdims)
>
>
>
>
> Test case reproducing the bug:
>
>
>
> from paraview.simple import *
> paraview.simple._DisableFirstRenderCameraReset()
> programmableSource1 = ProgrammableSource()
> programmableSource1.Script = \
> """gg=max(5.0,6.0)
> #This script generates a helix curve.
> #This is intended as the script of a 'Programmable Source'
> import math
>
> numPts = 80 # Points along Helix
> length = 8.0 # Length of Helix
> rounds = 3.0 # Number of times around
>
> #Get a vtk.PolyData object for the output
> pdo = self.GetPolyDataOutput()
>
> #This will store the points for the Helix
> newPts = vtk.vtkPoints()
> for i in range(0, numPts):
>    #Generate the Points along the Helix
>    x = i*length/numPts
>    y = math.sin(i*rounds*2*math.pi/numPts)
>    z = math.cos(i*rounds*2*math.pi/numPts)
>    #Insert the Points into the vtkPoints object
>    #The first parameter indicates the reference.
>    #value for the point. Here we add them sequentially.
>    #Note that the first point is at index 0 (not 1).
>    newPts.InsertPoint(i, x,y,z)
>
> #Add the points to the vtkPolyData object
> #Right now the points are not associated with a line -
> #it is just a set of unconnected points. We need to
> #create a 'cell' object that ties points together
> #to make a curve (in this case). This is done below.
> #A 'cell' is just an object that tells how points are
> #connected to make a 1D, 2D, or 3D object.
> pdo.SetPoints(newPts)
>
> #Make a vtkPolyLine which holds the info necessary
> #to create a curve composed of line segments. This
> #really just hold constructor data that will be passed
> #to vtkPolyData to add a new line.
> aPolyLine = vtk.vtkPolyLine()
>
> #Indicate the number of points along the line
> aPolyLine.GetPointIds().SetNumberOfIds(numPts)
> for i in range(0,numPts):
>    #Add the points to the line. The first value indicates
>    #the order of the point on the line. The second value
>    #is a reference to a point in a vtkPoints object. Depends
>    #on the order that Points were added to vtkPoints object.
>    #Note that this will not be associated with actual points
>    #until it is added to a vtkPolyData object which holds a
>    #vtkPoints object.
>    aPolyLine.GetPointIds().SetId(i, i)
>
> #Allocate the number of 'cells' that will be added. We are just
> #adding one vtkPolyLine 'cell' to the vtkPolyData object.
> pdo.Allocate(1, 1)
>
> #Add the poly line 'cell' to the vtkPolyData object.
> pdo.InsertNextCell(aPolyLine.GetCellType(), aPolyLine.GetPointIds())
>
> #The Helix is ready to plot! Click 'Apply'.
> """
> renderView1 = GetActiveViewOrCreate('RenderView')
> programmableSource1Display = Show(programmableSource1, renderView1)
> renderView1.ResetCamera()
> Render()
>
>
>
> Guillaume Jacquenot
>
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-- 
Cory Quammen
Staff R&D Engineer
Kitware, Inc.