[Paraview] compare two datasets in paraview

[Berk Geveci]

In 3.8, this will be:

output.PointData.append(inputs[0].Points - inputs[1].Points, 'point_difference')

in the programmable filter. In the Python calculator, it will be:

inputs[0].Points - inputs[1].Points

and you'll choose the name of the array in another entry.

You can do this with the development version if you build it from
source. You will need to compile with Python support and have NumPy
installed.

-berk


On Thu, Jan 28, 2010 at 9:41 AM, Eric E. Monson <emonson at cs.duke.edu> wrote:
> Hey again,
>
> There may be other ways, too, but you can do this with the Python Programmable Filter (PPF). To have two inputs to the PPF you need to select both data sets in the pipeline (on mac it's command-click, others may be control-click...) and then apply the filter. Here is a sample script which subtracts the coordinates of the two data sets from each other and makes a new vector data attribute out of that difference:
>
> # ===========
> from paraview.vtk import vtkFloatArray
>
> in0 = self.GetInputDataObject(0,0)
> in1 = self.GetInputDataObject(0,1)
> pti0 = in0.GetPoints()
> pti1 = in1.GetPoints()
> numPts = in0.GetNumberOfPoints()
>
> vec = vtkFloatArray()
> vec.SetName('coordDiff')
> vec.SetNumberOfComponents(3)
> vec.SetNumberOfTuples(numPts)
>
> for ii in range(numPts):
>        # compute velocity and put in vec
>        tmpDiff = [0.0, 0.0, 0.0]
>        pos1 = pti1.GetPoint(ii)
>        pos0 = pti0.GetPoint(ii)
>        for kk in range(len(tmpDiff)):
>                tmpDiff[kk] = pos1[kk] - pos0[kk]
>        vec.SetTuple3(ii,tmpDiff[0],tmpDiff[1],tmpDiff[2])
>
> out1 = self.GetOutputDataObject(0)
> out1.ShallowCopy(in0)
> out1.GetPointData().AddArray(vec)
> # ===========
>
> This doesn't do any checking for matching IDs of the points or whether both sets have the same number of points (I have an extended script which searches for points with matching ID if you need help doing that), but if they really match it will work. (Others can let you know if there are better ways of doing this or if I've done anything "non-standard" in my script.)
>
> Good luck,
> -Eric
>
> ------------------------------------------------------
> Eric E Monson
> Duke Visualization Technology Group
>
>
> On Jan 28, 2010, at 7:10 AM, Kalpana Kanthasamy wrote:
>
>> hi
>>
>> me again, how do I compare the co-ordinates of two datasets in paraview.. I have two dataset..of the same set of points but their cordinates differ slightly. I need the number of these co-ordinates
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