64 bit support

[looooo]

Comment:

Trying to setup a feedstock for pastix, I run into this issue:

-- Found SCOTCH: $PREFIX/lib/libscotch.so;$PREFIX/lib/libscotcherr.so;$BUILD_PREFIX/x86_64-conda-linux-gnu/sysroot/usr/lib/libpthread.so;$PREFIX/lib/libz.so;$BUILD_PREFIX/x86_64-conda-linux-gnu/sysroot/usr/lib/libm.so;$BUILD_PREFIX/x86_64-conda-linux-gnu/sysroot/usr/lib/librt.so
CMake Error at CMakeLists.txt:448 (message):
  PASTIX_INT64 is enabled and provided Scotch is not compiled with int64
  support, please build with -DPASTIX_INT64=OFF or install a 64 bits version
  of Scotch.

while scotch is optional for pastix, it might be possible to compile scotch with 64 bit support?

[looooo]

#90

[minrk]

closed by #90, thanks!

[Tobias-Fischer]

Are you sure @minrk? I think @looooo said that it does not fix this issue.

[looooo]

I can't reproduce this issue with libscotch 7.0.5. So I guess it's ok to close this issue. Thanks.

[looooo]

conda-forge/pastix-feedstock#5

[looooo]

hmm strange locally I cannot reproduce with pixi, but the feedstock builds still fail with the same issue

CMake Error at CMakeLists.txt:455 (message):
  PASTIX_INT64 is enabled and provided Scotch is not compiled with int64
  support, please build with -DPASTIX_INT64=OFF or install a 64 bits version
  of Scotch.

also running conda-build locally seems to work fine.

[minrk]

Sorry, I misunderstood! I'll let @looooo decide when to close

[looooo]

Seems like 64bit works on osx arm, but not on the other platforms.

[looooo]

is it possible to add this test to the feedstock?

#include <stdio.h>
#include <stdint.h>
#include <scotch.h>
int main() {
  if (sizeof(SCOTCH_Num) == 8)
    return 0;
  else
    return 1;
}

Actually I don't understand why osx-arm64 uses 64 bit ints as the definition seems to be the same for different platforms:

typedef int SCOTCH_Num;

[minrk]

sizeof(SCOTCH_Num) is 4 on osx-arm64 with current builds of scotch 7.0.5 build 2

[minrk]

#94 adds a test. It passes on all platforms (including osx-arm64, which I had to test locally) if the assert is that sizeof(SCOTCH_Num) == 4, is that what you expect?

[looooo]

For 64bit size of(Scotch_Num) should be 8. But it's possible to build pastix with PASTIX_INT64=Off.
Now the only question is why the osx-arm build of pastix reports:

CMake Error at CMakeLists.txt:458 (message):
  PASTIX_INT64 is disabled and provided Scotch is not compiled with int32
  support, please build with -DPASTIX_INT64=ON or install a 32 bits version
  of Scotch.

the pastix osx-arm build uses libscotch: 7.0.5-h9f781f6_2

[minrk]

Check the full cmake error log, it might be misinterpreting an error

[looooo]

-- Performing Test SCOTCH_Num_4
-- Performing Test SCOTCH_Num_4 - Failed
-- Performing Test SCOTCH_Num_8
-- Performing Test SCOTCH_Num_8 - Failed
-- Found SCOTCH: /Users/runner/miniforge3/conda-bld/pastix-split_1732099993387/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placeh/lib/libscotch.dylib;/Users/runner/miniforge3/conda-bld/pastix-split_1732099993387/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placeh/lib/libscotcherr.dylib;/Users/runner/miniforge3/conda-bld/pastix-split_1732099993387/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placeh/lib/libz.dylib;/Applications/Xcode_15.2.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.0.sdk/usr/lib/libm.tbd
CMake Error at CMakeLists.txt:458 (message):
  PASTIX_INT64 is disabled and provided Scotch is not compiled with int32
  support, please build with -DPASTIX_INT64=ON or install a 32 bits version
  of Scotch.

seems like both tests fail. Is it possible that there might be an issue with cross compiling?

[minrk]

If the test involves executing the result, that definitely cannot work. You'll need to bypass that, as is common in cross compiling. You'll have to check that project's cmake to see how exactly.

[looooo]

Ok I will look into this. Just to clarify:
Here we are also cross-compiling. How is it possible this test can run here?

[minrk]

You can't generally expect to run compiled executables for testing the environment when cross compiling. That means you either need to be able to compute the test without execution (possible in this particular case, since SCOTCH_Num is defined purely in the header and doesn't require compiling to find), or allow explicit user input to provide the answer to the test without running it, which is the more general solution.

Basically, this check and any call to check_c_source_runs must always be optional and overridable if you want to support cross compilation, e.g. by user setting -DPTSCOTCH_Num_8=ON. But it looks like this code explicitly prohibits that to ensure the executable test always runs, which would be a mistake.

[looooo]

still there is something odd. When I compile pastix locally on osx-arm I see the following:

-- Performing Test SCOTCH_Num_4
-- Performing Test SCOTCH_Num_4 - Failed
-- Performing Test SCOTCH_Num_8
-- Performing Test SCOTCH_Num_8 - Success

also the tests seem to work.

[minrk]

I'm not sure what's up there, since the test seems to be giving the wrong result. Here's a simple pixi project which shows sizeof(SCOTCH_Num) is 4: https://gist.github.com/minrk/b29f7a1f89844fbce2d695a2ba944f68

Run it with:

pixi run test

which should install the env, run the build, and output:

✨ Pixi task (test): ./test
sizeof(SCOTCH_Num)=4

[looooo]

Thanks for creating the pixi-project. I tried it and can reproduce the test with the same output sizeof(SCOTCH_Num)=4

Now I added the test to the calculix/pastix project and there I get:

✨ Pixi task (test_libscotch_test): ./build/libscotch_test
sizeof(SCOTCH_Num)=8

looking at the pixi.lock file I see that I used a different build of libscotch. Actually a build I compiled myself for 64 bit support... stupid me, sry for the noise.

[minrk]

Glad it's figured out!