Trouble installing hmatrix through MSYS2 on Windows 10

Question

I've been trying to install hmatrix on my (64-bit) Windows 10 computer; after searching through and trying many possible solutions (including the instructions under "Windows" and "Alternative Windows Build" given here), I decided to pursue the course of action given on this Reddit thread.

However, when I type in the command

cabal install hmatrix -fopenblas --extra-lib-dir=${c:\msys64\mingw64\bin} --extra-include-dir=${c:\msys64\mingw64\include}

into the MSYS2 shell, the following log is given:

Resolving dependencies... 
Configuring hmatrix-0.17.0.2...
Failed to install hmatrix-0.17.0.2
Build log ( C:\Users\Christian\AppData\Roaming\cabal\logs\hmatrix-0.17.0.2.log ):
Configuring hmatrix-0.17.0.2...
cabal.exe: Missing dependency on a foreign library:
* Missing C library: libopenblas
This problem can usually be solved by installing the system package that
provides this library (you may need the "-dev" version). If the library is
already installed but in a non-standard location then you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.
cabal: Leaving directory 'C:\msys64\tmp\cabal-tmp-4244\hmatrix-0.17.0.2'
cabal.exe: Error: some packages failed to install:
hmatrix-0.17.0.2 failed during the configure step. The exception was:
ExitFailure 1

However, when I check the directory c:\msys64\mingw64\bin, I see that libopenblas.dll is right there; I don't know why cabal can't seem to find it.

Any insight into why this is not working or what to do?

UPDATE: The files libopenblas.dll.a and libopenblas.a are in the directory c:\msys64\mingw64\lib. Is it possible I need to somehow include this directory as well? (If I do, how would I do that?)

I also downloaded the files in Alex Vorobiev's comment below and put them in c:\msys64\mingw64\bin if they are .dlls or c:\msys64\mingw64\lib if they are .libs. The header files were already contained in c:\msys64\include\openblas.

I tried several variations on the command in the original post after making these changes, including switching \bin with \lib and switching \include with \include\openblas, but all of them still give the same error.

Answer 1

I'm a bit suspicious about the

 if os(windows)
    if flag(openblas)
        extra-libraries:    libopenblas

in the cabal file, could you unpack it and remove the "lib" part? If that doesn't work please post a log with -v3 output. I've seen quite a few people with troubles installing this package. So could you also open a ticket on the GHC bug tracker if this doesn't work (and CC me "Phyx-")?

Secondly, you never said which version of GHC you're using. 8.0.1 should have far less trouble (and won't need the hack to get it working in GHCi) since the runtime linker has been overhauled and should be much better on Windows. 8.0.2 will likely include the new import libraries support as well.