Initialise PETSc, drop LinSolveExprs in lower_petsc, add PETScStruct, create matvec callback and move files into PETSc folder #40

	name: CI-petsc

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true

	on:
	# Trigger the workflow on push or pull request,
	# but only for the master branch
	push:
	branches:
	- master
	pull_request:
	branches:
	- master

	jobs:
	test-petsc:
	name: pytest-petsc
	runs-on: ubuntu-22.04
	strategy:
	matrix:
	python-version: ['3.8', '3.9']

	steps:
	- uses: actions/setup-python@v5
	with:
	python-version: ${{ matrix.python-version }}

	- name: Checkout devito
	uses: actions/checkout@v4

	- name: Install dependencies
	run: \|
	sudo apt-get update && sudo apt-get install mpich pkgconf libopenblas-serial-dev -y

	- name: Download and install PETSc
	run: \|
	mkdir -p $HOME/petsc
	cd $HOME/petsc
	git clone -b release https://gitlab.com/petsc/petsc.git petsc
	cd petsc
	git pull
	./configure --with-fortran-bindings=0 --with-openblas-include=$(pkgconf --variable=includedir openblas) --with-openblas-lib=$(pkgconf --variable=libdir openblas)/libopenblas.so PETSC_ARCH=devito_build
	make all

	- name: Install Python dependencies
	run: \|
	pip3 install --upgrade pip
	pip3 install --no-binary numpy numpy
	python -c "import numpy; numpy.show_config()"
	pip3 install -e .[extras,mpi,tests]

	- name: Test with pytest
	run: \|
	export PETSC_DIR=$HOME/petsc/petsc
	export PETSC_ARCH=devito_build
	python3 scripts/clear_devito_cache.py
	python3 -m pytest tests/test_petsc.py

	- name: Upload coverage to Codecov
	uses: codecov/codecov-action@v4
	with:
	token: ${{ secrets.CODECOV_TOKEN }}
	name: pytest-petsc

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