How to deal with **OpenMP** for **Open3D** ?

[jiapei100]

Checklist

• [X] I have searched for similar issues.
• [X] For Python issues, I have tested with the latest development wheel.
• [X] I have checked the release documentation and the latest documentation (for master branch).

My Question

How to deal with OpenMP for Open3D ?

[ 15%] Building CXX object cpp/open3d/core/CMakeFiles/core.dir/Indexer.cpp.o
......
....../Open3D/cpp/open3d/geometry/Image.cpp:163: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  163 | #pragma omp parallel for collapse(2) schedule(static) \
      | 
....../Open3D/cpp/open3d/geometry/Image.cpp:196: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  196 | #pragma omp parallel for collapse(2) schedule(static) \
      | 
....../Open3D/cpp/open3d/geometry/Image.cpp:281: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  281 | #pragma omp parallel for collapse(2) schedule(static) \
      | 
....../Open3D/cpp/open3d/geometry/Image.cpp:303: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  303 | #pragma omp parallel for schedule(static) \
      | 
....../Open3D/cpp/open3d/geometry/Image.cpp:323: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  323 | #pragma omp parallel for collapse(2) schedule(static) \
      | 
....../Open3D/cpp/open3d/geometry/Image.cpp:350: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  350 | #pragma omp parallel for collapse(2) schedule(static) \
      | 
....../Open3D/cpp/open3d/geometry/Image.cpp:390: warning: ignoring ‘#pragma omp parallel’ [-Wunknown-pragmas]
  390 | #pragma omp parallel for collapse(2) schedule(static) \
      | 
[ 15%] Building CXX object cpp/open3d/geometry/CMakeFiles/geometry.dir/ImageFactory.cpp.o

Is it Open3D? or is it Intel OneAPI's mpi ???

[nigels-com]

Can you provide some information about the platform and compiler toolchain? Snippets of the initial cmake log would likely shed some light.

[ssheorey]

This is not related to OneAPI - it is OpenMP and looks like your compiler does not support it. Everything should still build and run, but will be slower since you will not be able to use multiple CPU cores.

[ssheorey]

Closing for now - please add more information about your environment if you still need help.