[vtkusers] Importing lagrangian data from openfoam into numpy arrays

[Cory Quammen]

Victor,

To read in your file with VTK+Python, use

import vtk
reader = vtk.vtkPolyDataReader()
reader.SetFileName("myfile.vtk")
reader.Update()

Then, to convert your point data to numpy arrays, use

from vtk.numpy_interface import dataset_adapter as dsa
mydata = dsa.WrapDataObject(reader.GetOutput())
origId = mydata.PointData['origId']
ImpCpuId = mydata.PointData['lmpCpuId']

`oridId` and `ImpCpuId` are now NumPy-like arrays you can use like you
would NumPy arrays.

Paul's suggestion at looking at the blog posts for more comprehensive
information is a good one.

HTH,
Cory


On Thu, Mar 30, 2017 at 4:13 AM, Paul Melis <paul.melis at surfsara.nl> wrote:
> Hi Victor,
>
> Perhaps this series of blog posts on VTK+numpy integration can help you
> further? I haven't used that stuff too much myself, but I believe you should
> be able to use VTK's numpy adapters to get all your data as numpy arrays:
>
> https://blog.kitware.com/improved-vtk-numpy-integration/
>
> Regards,
> Paul
>
>
> On 29-03-17 13:55, Victor Koppejan - TNW wrote:
>>
>> Hi Everyone,
>>
>> I'd like to import data from openfoam lagrangian particle (saved as binary
>> or ascii vtk files) in simulations into numpy-arrays. The data is either in
>> scalar or vector format. I can't find what I want in the examples or other
>> online tutorials. Does anyone have a suggestion can you refer me to online
>> material?
>>
>> The data is stored as polydata, see a short version of the file (in this
>> case ascii) contents below:
>>
>> # vtk DataFile Version 2.0
>> linkCG2-500cmh-run1
>> ASCII
>> DATASET POLYDATA
>> POINTS 187550 float
>> <lots of points>
>> POINT_DATA 187550
>> FIELD attributes 8
>> origId 1 187550 float
>> <lots of points>
>> lmpCpuId 1 187550 float
>> <lots of points>
>>
>> etc., here origId and lmpCpuId are scalar variables, after this there's 8
>> more variables. I can read it all in in matlab but I've been trying to move
>> all my computations to python.
>>
>> Thanks in advance for your help.
>>
>> Kind regards,
>>
>> Victor
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>
>
> --
>
> Paul Melis
> | Visualization group leader & developer | SURFsara |
> | Science Park 140 | 1098 XG Amsterdam |
> | T 020 800 1312 | paul.melis at surfsara.nl | www.surfsara.nl |
>
> _______________________________________________
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>
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>
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>
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-- 
Cory Quammen
Staff R&D Engineer
Kitware, Inc.