Using OpenBLAS for optimized LAPACK functions via lapack-reference

[larsoner]

---

Is your feature request related to a problem? Please describe.

I would like to build a project using OpenBLAS for BLAS + LAPACK functions. It seems like this should be possible with something like:

  "dependencies": [
    "openblas",
    {
      "name": "lapack-reference",
      "features": [
        "blas-select"
      ]
    }

But this results in cmake:

-- Looking for sgemm_
-- Looking for sgemm_ - found
-- Found BLAS: D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/lib/openblas.lib  
-- Using VCPKG FindLAPACK from package 'lapack-reference'
-- Looking for cheev_
-- Looking for cheev_ - not found
CMake Error at build/vcpkg_installed/x64-windows/share/lapack/FindLAPACK.cmake:522 (message):
Error:   A required library with LAPACK API not found.  Please specify library
  location.

Proposed solution
I am not sure, but it seems like the OpenBLAS port should have an option to expose its LAPACK capabilities so that it can be selected as a backend, and/or lapack-reference should know how to find OpenBLAS's LAPACK capabilities.

Describe alternatives you've considered
I'm going to try using clapack as a workaround for now, but it probably is not as optimized as OpenBLAS, so it'll be slower for end users.

[larsoner]

... and #21479 is possibly relevant

[larsoner]

And trying my alternative:

  "dependencies": [
    "openblas",
    "clapack",
  ...

Results in:

-- Looking for sgemm_
-- Looking for sgemm_ - found
-- Found BLAS: D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/lib/openblas.lib  
-- Using VCPKG FindLAPACK from package 'clapack'
-- Looking for pthread.h
-- Looking for pthread.h - not found
-- Found Threads: TRUE  
-- LAPACK_DLL_DIR: D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/include/../bin;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/include/../bin
-- Found LAPACK: optimized;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/lib/lapack.lib;optimized;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/lib/libf2c.lib;optimized;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/lib/openblas.lib;debug;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/debug/lib/lapackd.lib;debug;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/debug/lib/libf2cd.lib;debug;D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/debug/lib/openblas.lib  
CMake Error at cmake/FindBLASImplementation.cmake:114 (set_target_properties):
Error:   Property INTERFACE_LINK_LIBRARIES may not contain link-type keyword
-- Looking for LAPACKE_dlange
  "optimized".  The INTERFACE_LINK_LIBRARIES property may contain
  configuration-sensitive generator-expressions which may be used to specify
  per-configuration rules.

I also tried just setting the dependencies as "blas", "lapack" because this seems like the most straightforward case, but I still get:

The following packages will be built and installed:
    blas[core]:x64-windows -> 1#1
    hdf5[core,szip,zlib]:x64-windows -> 1.12.1#4
    lapack[core]:x64-windows -> 2022-02-22
  * lapack-reference[blas-select,core,noblas]:x64-windows -> 3.10.0
    matio[core,hdf5,mat73,zlib]:x64-windows -> 1.5.19#1
  * openblas[core]:x64-windows -> 0.3.20
...
-- Found BLAS: D:/a/openmeeg/openmeeg/build/vcpkg_installed/x64-windows/lib/openblas.lib  
-- Using VCPKG FindLAPACK from package 'lapack-reference'
-- Looking for cheev_
-- Looking for cheev_ - not found
CMake Error at build/vcpkg_installed/x64-windows/share/lapack/FindLAPACK.cmake:522 (message):
Error:   A required library with LAPACK API not found.  Please specify library
-- Configuring incomplete, errors occurred!
  location.
See also "D:/a/openmeeg/openmeeg/build/CMakeFiles/CMakeOutput.log".
Call Stack (most recent call first):
See also "D:/a/openmeeg/openmeeg/build/CMakeFiles/CMakeError.log".
  build/vcpkg_installed/x64-windows/share/lapack/vcpkg-cmake-wrapper.cmake:9 (_find_package)
  vcpkg/scripts/buildsystems/vcpkg.cmake:778 (include)
  cmake/FindBLASImplementation.cmake:79 (find_package)
  cmake/thirdParties.cmake:1 (include)
  CMakeLists.txt:20 (include)

[JackBoosY]

Maybe #21479 can fix this issue?

[larsoner]

It might. FWIW I tried that PR and it failed for me locally. If it helps, I can try again and post the traceback.

[JackBoosY]

It might. FWIW I tried that PR and it failed for me locally. If it helps, I can try again and post the traceback.

It's still WIP, Robert doesn't have more time to handle that PR currently.

[paolomunarini]

Hello, I'm having the same issue only when installing with the following custom triplet:

set(VCPKG_TARGET_ARCHITECTURE x64)
set(VCPKG_CRT_LINKAGE dynamic)
set(VCPKG_LIBRARY_LINKAGE dynamic)
set(VCPKG_PLATFORM_TOOLSET v140)

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[larsoner]

It would be nice if #24327 or similar took care of this, but I'm not sure it will.

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