metabrush/installation_notes.md

Installation notes

On Windows, we need to install an up-to-date MinGW/MSYS2 toolchain, together with the packages required by the haskell-gi libraries (for GTK), as well as the hmatrix library.

With an MSYS2 installation, the following environment variables will need to be set (with MSYS2 installed at C:\msys64):

PATH: C:\msys64\mingw64\bin;C:\msys64\usr\bin
PKG_CONFIG_PATH: C:\msys64\mingw64\lib\pkgconfig
XDG_DATA_DIRS: C:\msys64\mingw64\share;C:\msys64\usr\share

Then we install some necessary packages using the following command:

pacman -S -q --noconfirm mingw64/mingw-w64-x86_64-pkg-config mingw64/mingw-w64-x86_64-gobject-introspection mingw64/mingw-w64-x86_64-gtksourceview3

Possible errors

pkg-config could not be found

The error

The program 'pkg-config' is required but it could not be found.

means that pkg-config couldn't be found on the path. Run the command

pacman -S -q --noconfirm mingw64/mingw-w64-x86_64-pkg-config

to install it.

gobject could not be found

An error such as

The pkg-config package 'gobject' is required but it could not be found.

indicates missing dependencies for the haskell-gi suite of packages. Ensure these are installed by running the aforementioned pacman command. Also check that the packages are registered with pkg-config using the command

pkg-config --list-all

If packages such as cairo, gtk etc do not appear, this means PKG_CONFIG_PATH is not set correctly. Search for *.pc files in your MSYS2 installation, and ensure their paths are included in PKG_CONFIG_PATH.

...is a relative path which makes no sense

Any error of the form:

include-dirs: /mingw64/bin is a relative path which makes no sense

indicates that one of the packages is incorrectly using a Unix-style path. This was the case with fontconfig, which was resolved in this patch.

At the time of writing, another dependency suffers from the same issue: graphite2. To fix this, change its pkg-config package file graphite2.pc as follows:

>>> before:
Libs: -L/mingw64/lib -lgraphite2
Cflags: -I/mingw64/include

>>> after:
Libs: -L${libdir} -lgraphite2
Cflags: -I${includedir}

Missing C library blas or lapack

The error message

Missing dependencies on foreign libraries:
* Missing (or bad) C libraries: blas, lapack

indicates that cabal could not find the C libraries that hmatrix depends on.

These can be downloaded here. You will need:

• BLAS x64 dll,
• LAPACK x64 dll,

Put these in some folder, say "C:/GSL", then:

• add the folder to the PATH environment variable,
• add the following to your cabal.project file:

package hmatrix
  extra-lib-dirs: "C:/GSL"
  extra-include-dirs: "C:/GSL"

The code execution cannot proceed because libgfortran_64-3.dll was not found

An error such as

The code execution cannot proceed because libgfortran_64-3.dll was not found

or

The code execution cannot proceed because libgcc_s_seh_64-1.dll was not found

indicates that a dependency of BLAS/LAPACK could not be loaded. Download these DLLs and add them to the PATH.

addDLL: library not loaded

The error message

addDLL: C:\GSL\libblas or dependencies not loaded. (Win32 error 126)

means that GHC was not able to find the BLAS library, or a dependency thereof.

Follow the previous two steps to ensure both the library and its dependencies can be found.

Unknown symbol dgesvd_

An error of the form

ghc.exe:  | MetaBrush\dist-newstyle\build\x86_64-windows\ghc-8.8.4\hmatrix-0.20.0.0\build\libHShmatrix-0.20.0.0-inplace.a: unknown symbol `dgesvd_'

indicates that GHC was not able to load symbols for the hmatrix dependency. This should be solved in the same way as the previous error.