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Fixed detection of OpenBLAS and LAPACK on Ubuntu 18.04 with arch x86-64#19343

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HungWoeiNeoh:ubuntu_openblas_lapack_fix
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Fixed detection of OpenBLAS and LAPACK on Ubuntu 18.04 with arch x86-64#19343
HungWoeiNeoh wants to merge 1 commit intoopencv:4.xfrom
HungWoeiNeoh:ubuntu_openblas_lapack_fix

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@HungWoeiNeoh
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@HungWoeiNeoh HungWoeiNeoh commented Jan 18, 2021 •
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Fixes the cmake detection of OpenBLAS and LAPACK libraries on Ubuntu with arch x86-64

A similar fix can be applied for other architectures too.

Source: #9953, only partially resolves it.

Tested this on a Docker container, Ubuntu 18.04 with GCC 7.5.0, OpenCV builds successfully, and the relevant cmake output for OpenBLAS detection is as follows:

-- Found OpenBLAS libraries: /usr/lib/x86_64-linux-gnu/libopenblas.so
-- Found OpenBLAS include: /usr/include/x86_64-linux-gnu
-- LAPACK(OpenBLAS): LAPACK_LIBRARIES: /usr/lib/x86_64-linux-gnu/libopenblas.so
-- LAPACK(OpenBLAS): Support is enabled.

This patch has not been tested on other architectures/OS, but it should not affect any other architecture/OS

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

  • I agree to contribute to the project under Apache 2 License.
  • To the best of my knowledge, the proposed patch is not based on a code under GPL or other license that is incompatible with OpenCV
  • The PR is proposed to proper branch
  • There is reference to original bug report and related work
  • There is accuracy test, performance test and test data in opencv_extra repository, if applicable
    Patch to opencv_extra has the same branch name.
  • The feature is well documented and sample code can be built with the project CMake

@alalek
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alalek commented Jan 18, 2021

Please provide details about use case.

Docker file is preferable:

FROM ubuntu:18.04

RUN apt update && apt install -y git cmake make g++ \
    libopenblas-dev

RUN git clone --branch ubuntu_openblas_lapack_fix --depth=1 https://github.com/HungWoeiNeoh/opencv
RUN mkdir opencv_build
WORKDIR opencv_build
RUN cmake ../opencv -DWITH_IPP=OFF && make -j1 opencv_test_core

Results:

-- Found OpenBLAS libraries: /usr/lib/x86_64-linux-gnu/libopenblas.so
-- Found OpenBLAS include: /usr/include/x86_64-linux-gnu
-- LAPACK(OpenBLAS): LAPACK_LIBRARIES: /usr/lib/x86_64-linux-gnu/libopenblas.so
CMake Warning at cmake/OpenCVFindLAPACK.cmake:29 (message):
  LAPACK(OpenBLAS): CBLAS/LAPACK headers are not found in
  '/usr/include/x86_64-linux-gnu;/usr/include'
Call Stack (most recent call first):
  cmake/OpenCVFindLAPACK.cmake:103 (ocv_lapack_check)
  CMakeLists.txt:710 (include)


-- Could NOT find Atlas (missing: Atlas_CLAPACK_INCLUDE_DIR Atlas_CBLAS_LIBRARY Atlas_BLAS_LIBRARY) 
-- Looking for sgemm_
-- Looking for sgemm_ - found
-- Found Threads: TRUE  
-- A library with BLAS API found.
-- Looking for cheev_
-- Looking for cheev_ - found
-- A library with LAPACK API found.
...

--   Other third-party libraries:
...
--     Lapack:                      NO

So this patch doesn't seem to work.
(Ubuntu package is broken as stated in the issue)

P.S. Always clear CMake cache (build directory) if dependencies are changed. We need reproducible results.

@mshabunin
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mshabunin commented Jan 18, 2021 •
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@HungWoeiNeoh , I tried to fix the detection too, but did not finish it: mshabunin@651e95e

As I remember it was important to find correct header using _find_header_file_in_dirs.

@HungWoeiNeoh
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HungWoeiNeoh commented Jan 19, 2021 •
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Hi, what do you mean by use case? Do you mean the reason I'm building OpenCV?

You still need to install liblapacke-dev, which will install the LAPACK headers, as mentioned in the issue. The headers will be installed in /usr/include. The fix is to make sure that the cmake file is able to detect the LAPACK headers if you installed liblapacke-dev

@asenyaev
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asenyaev commented Apr 8, 2021

jenkins cn please retry a build

@catree
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catree commented May 11, 2021

I believe you should inform this issue at the OpenBLAS Ubuntu/distrib maintainer level.

Because when you build OpenBLAS from source, it will correctly install the lapacke.h header:

cblas.h
f77blas.h
lapacke_config.h
lapacke.h
lapacke_mangling.h
lapacke_utils.h
lapack.h
openblas_config.h

While in Bionic (18.04):

/usr/include/x86_64-linux-gnu/cblas-openblas.h
/usr/include/x86_64-linux-gnu/f77blas.h
/usr/include/x86_64-linux-gnu/openblas_config.h
/usr/lib/x86_64-linux-gnu/libopenblas.a
/usr/lib/x86_64-linux-gnu/libopenblas.so
/usr/lib/x86_64-linux-gnu/libopenblasp-r0.2.20.a
/usr/lib/x86_64-linux-gnu/openblas/libblas.a
/usr/lib/x86_64-linux-gnu/openblas/libblas.so
/usr/lib/x86_64-linux-gnu/openblas/liblapack.a
/usr/lib/x86_64-linux-gnu/openblas/liblapack.so
/usr/lib/x86_64-linux-gnu/pkgconfig/blas-openblas.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/lapack-openblas.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/openblas.pc
/usr/share/doc/libopenblas-dev/changelog.Debian.gz
/usr/share/doc/libopenblas-dev/copyright

In Impish:

/usr/include/x86_64-linux-gnu/openblas-pthread/cblas.h
/usr/include/x86_64-linux-gnu/openblas-pthread/f77blas.h
/usr/include/x86_64-linux-gnu/openblas-pthread/openblas_config.h
/usr/lib/x86_64-linux-gnu/openblas-pthread/cmake/openblas/OpenBLASConfig.cmake
/usr/lib/x86_64-linux-gnu/openblas-pthread/cmake/openblas/OpenBLASConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.a
/usr/lib/x86_64-linux-gnu/openblas-pthread/libblas.so
/usr/lib/x86_64-linux-gnu/openblas-pthread/liblapack.a
/usr/lib/x86_64-linux-gnu/openblas-pthread/liblapack.so
/usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblas.a
/usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblas.so
/usr/lib/x86_64-linux-gnu/openblas-pthread/libopenblasp-r0.3.13.a
/usr/lib/x86_64-linux-gnu/openblas-pthread/pkgconfig/blas-openblas.pc
/usr/lib/x86_64-linux-gnu/openblas-pthread/pkgconfig/lapack-openblas.pc
/usr/lib/x86_64-linux-gnu/openblas-pthread/pkgconfig/openblas.pc
/usr/share/doc/libopenblas-pthread-dev/changelog.Debian.gz
/usr/share/doc/libopenblas-pthread-dev/copyright

@vpisarev
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vpisarev commented May 25, 2021 •
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@alalek, shall we backport alway-available-Lapack patch to the master branch? If I remember correctly, BLAS/Lapack detection part was significantly reworked there

@catree catree mentioned this pull request Jun 11, 2021
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@asmorkalov asmorkalov mentioned this pull request Mar 24, 2025
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@HungWoeiNeoh @alalek @mshabunin @asenyaev @catree @vpisarev @asmorkalov