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I'm trying to build OpenCV (4.5.1) from source, from the CMake-GUI output, there are 2 third-party libraries displayed as NO.

  Other third-party libraries:
    Intel IPP:                   2020.0.0 Gold [2020.0.0]
           at:                   C:/Users/opencv-4.5.1/_build/3rdparty/ippicv/ippicv_win/icv
    Intel IPP IW:                sources (2020.0.0)
              at:                C:/Users/opencv-4.5.1/_build/3rdparty/ippicv/ippicv_win/iw
    Lapack:                      NO
    Eigen:                       NO
    Custom HAL:                  NO
    Protobuf:                    build (3.5.1)

I want best performance of OpenCV, so I'd like to check what's the performance gain if I install Lapack or Eigen?

  • I think I will skip Lapack, since it seems to need a FORTRAN compiler which I don't have in Windows. –  Jan 30 '21 at 07:48
  • Where did you hear that lapack or eigen will increase performance of opencv and how ? – Yunus Temurlenk Jan 30 '21 at 15:10
  • @YunusTemurlenk That's my own assumption, I have to say. My logic is like this: if lapack or eigen will not improve performance, why not just remove it from opencv's 3rd party libraries, which are already way too many. –  Jan 31 '21 at 08:40
  • It's frustrating that nobody knows. Nobody knows what `WITH_LAPACK` and `WITH_EIGEN` do and they are left forever undocumented. – Константин Ван Dec 14 '22 at 09:15

1 Answers1

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The actual functions you get when eigen is enabled.

Eigen will allow you a specific set of matrix operations but I don't think many python opencv scripts use it therefore it is optional.

https://docs.opencv.org/4.x/d0/daf/group__core__eigen.html

Eric Aya
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Egbert Nierop
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