# Question About MPI max Numprocs

**URL:** <https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909>\
**Category:** Development\
**Created:** [December 14, 2023, 8:30pm UTC](https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909 "2023-12-14T20:30:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Rafael\_Scatena](https://discourse.vtk.org/user_avatar/discourse.vtk.org/rafael_scatena/32/7820_2.png) [@Rafael\_Scatena](https://discourse.vtk.org/u/Rafael_Scatena)\
**Post date:** [December 14, 2023, 8:30pm UTC](https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909/1 "2023-12-14T20:30:18Z")

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I have build VTK with MPI enabled and mpimaxnumprocs=64. When I build my app I print the value of VTK\_MPI\_NUMPROCS and the value I get is 2. Do somebody know what is the issue?

Thank you

 ![image](https://discourse.vtk.org/uploads/default/original/2X/8/84f986d0a8a7d2791cae96391ba9488ad69a95dd.png)  
 ![image](https://discourse.vtk.org/uploads/default/original/2X/7/73085739d3370e727bad2ff8a783742e3de0d433.png)  
 ![image](https://discourse.vtk.org/uploads/default/original/2X/d/d354e283ad8c8974ac6ae38e9af3814c1b80587e.png)

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**Author:** ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)\
**Post date:** [December 15, 2023, 9:31am UTC](https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909/2 "2023-12-15T09:31:12Z")

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VTK\_MPI\_NUMPROCS only matters for testing afaik, why does this matter for you ?

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**Author:** ![Paulo\_Carvalho](https://discourse.vtk.org/user_avatar/discourse.vtk.org/paulo_carvalho/32/370_2.png) [@Paulo\_Carvalho](https://discourse.vtk.org/u/Paulo_Carvalho)\
**Post date:** [December 15, 2023, 1:34pm UTC](https://discourse.vtk.org/t/question-about-mpi-max-numprocs/12909/3 "2023-12-15T13:34:25Z")

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Hello,

Please, try the `FORCE` modifier:

```bash
set(VTK_MPI_NUMPROCS 64 CACHE STRING "Number of MPI processes to use." FORCE)

```

This way, the value existing in the cache will be always set for each configuration cycle.

regards,

PC