Solve and Assemble Sparse Matrices

[HenningScheufler]

This feature adds the capability to create sparse matrices.

This requires the following features:

• sparse matrix class (CSR)
• design API to assemble matrix (minimal solution)
• pass matrix to external solvers (Ginkgo and Petsc)
• solve linear system with different algorithm (by specifying dictionary entires)

[happyKitesurfer]

Hello, do you plan to download and configure petsc with the cmake functionality? I'm trying to accomplish this (I'm still working on a small test):

cmake_minimum_required(VERSION 3.22.0)
project(petsc_test)


message("${CMAKE_BINARY_DIR}")

include(ExternalProject)
include(CheckLanguage)
message("installing petsc")
check_language(CUDA)
  if(CMAKE_CUDA_COMPILER)
          set(PETSC_ENABLE_CUDA 1)
else()
      set(PETSC_ENABLE_CUDA 0)
endif()

message("${PETSC_ENABLE_CUDA}")
message("${CMAKE_CUDA_COMPILER}")
cmake_path(GET "${CMAKE_CUDA_COMPILER}" PARENT_PATH CUDA_D)

ExternalProject_Add(
  petsc
 GIT_SHALLOW ON
 GIT_REPOSITORY "https://gitlab.com/petsc/petsc.git"
 GIT_TAG v3.22.2
 PREFIX ${CMAKE_BINARY_DIR}/petsc
 #BINARY_DIR ${CMAKE_BINARY_DIR}/petsc
 BUILD_IN_SOURCE YES
 #SOURCE_DIR ${CMAKE_BINARY_DIR}/petsc
#    SOURCE_DIR /home/michael/NeoFOAM/NeoFOAM/build/develop/_deps/petsc-src 
    #CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
 CONFIGURE_COMMAND   ./configure  --with-64-bit-indices=0 --with-precision=double --with-cuda=${PETSC_ENABLE_CUDA} --with-cuda-dir=/usr/local/cuda-12.3 --with-mpi=1 --with-fc=0 --force --with-32bits-pci-domain=1  --with-cc=mpicc --with-cxx=mpicxx --with-debugging=no --prefix=${CMAKE_BINARY_DIR}/petsc/opt/petsc
  BUILD_COMMAND make PETSC_DIR=${CMAKE_BINARY_DIR}/petsc/src/petsc PETSC_ARCH=arch-linux-c-opt all
 INSTALL_COMMAND make PETSC_DIR=${CMAKE_BINARY_DIR}/petsc/src/petsc PETSC_ARCH=arch-linux-c-opt install
)

When the download, configuration, build and installation works, I plan to write a small test in catch2 which includes petsc and solves a small matrix. Still have to replace some configuration options with cmake internal variables.

Should I make a branch and implement this?

[greole]

Please also take a look at #201 (currently i fail to propagate the compile definitions to ginkgo though). If you have a working version of building with PETSc please feel free to open a PR against the stack/linalg branch.