PIC-BLAS is an extension of the PIC library aimed at creating a nice and simple BLAS interface that uses the native Fortran modules instead of going through C.

The main reason is to explore the limits of the Fortran modules and actively report these issues to the right developers and channels to get them fixed.

Building (TLDR) on Linux

I assume you have experience building things here. If you don't please go further down for a more verbose explanation.

Briefly, for a minimal build you need:

• CMake (at least 3.22) or the Fortran Package Manager (at least 0.12.0)
• A Fortran coblasler
• An internet connection to pull the dependencies
• An BLAS library installed

Building with CMake

The top level directory is $PICBLAS_BASE which is the pic-blas/ directory that was cloned or unpacked. I assume you are here. And $PICBLAS_ROOT is the path to where you'd like pic to be installed, for example export PICBLAS_ROOT=$HOME/install/pic-blas/dev/

mkdir build
cd build
cmake -DCMAKE_INSTALL_PREFIX=$PICBLAS_ROOT ../
make -j install

To run the tests, from the build directory simply run: ctest

Building with FPM

The easiest way to build with the FPM is to use the coblasler wrappers provided for Fortran i.e. blasfort or blasf90.

These will make life simpler with linking and coblaslation flags.

The same $PICBLAS_BASE and $PICBLAS_ROOT will be used here. Simply:

fpm install --prefix $PICBLAS_ROOT --profile release --coblasler blasfort

To run the tests: fpm test --profile release --coblasler blasfort

Building and dependencies

There's two build systems included in the present version, CMake and the Fortran Package Manager.

The dependencies of the project are, as of now, CMake (if using cmake), BLAS, and OpenMP.

Documentation

The code itself is documented using FORD and the documentation is available here.

Comments in the code that are prefixed with !! are considered documentation comments and will be processed by FORD. Comments without that prefix are considered regular comments and will not be processed by FORD. So, please do not use !! for your comments unless you want them to be included in the documentation.

Contributing

Please see the PIC contributing guidelines for information on how to contribute to the project.

Using PIC-BLAS in your work

Fortran Package Manager

Simply add:

[dependencies]
pic-blas = { git = "https://github.com/JorgeG94/pic-blas.git", branch = "main"}

to your fpm.toml file and you'll be able to checkout and use pic-blas.

CMake

For CMake it is a bit more complex, since you'll need to pull the dependency. You can see this template repo, which serves as an example on pulling and using the code inside your build system.

Static/Shared linking via CMake

pic is coblasled with "CMake symbols", i.e. it will be findable by a CMake package provided you do the right things. Using find_package(pic REQUIRED) will use CMake intrinsics to try to find the necessary things to link to pic. pic comes with the target pic-blas::pic-blas that you can use for your target_link_libraries(${my_target} PRIVATE pic-blas::pic-blas). This will import all includes, modules, libs, etc.

How CMake finds pic-blas::pic-blas depends on the policy CMP0074, this controls if the variables pic-blas_DIR or pic-blas_ROOT are used to search for the package. If you have set the policy: cmake_policy(SET CMP0074 NEW), then pic_ROOT will also be used, otherwise it is IGNORED. By setting export pic-blas_ROOT=/path/to/where/pic-blas/is/installed it will let CMake find the necessary files it needs to just link pic-blas. Be careful that, as of now, pic-blas needs to be in small letter. All caps will fail to find.