# python-mumps -- the Python binding for MUMPS, the multifrontal sparse direct
# solver. From the Kwant project, not to be confused with MUMPS itself (which
# Fedora already ships as MUMPS 5.7.3).
#
# Why it is here: simnibs/simulation/fem.py does `import mumps` at module
# scope, so without it `import simnibs` fails outright -- the FEM solver is
# the core of SimNIBS, not an optional extra. This was the second missing
# runtime dependency found while making simnibs work out of the box (the
# first was python-cortech).

%global pypi_name python-mumps
%global mod_name  mumps

Name:           python-mumps
Version:        0.0.6
Release:        1%{?dist}
Summary:        Python bindings for the MUMPS sparse direct solver

# LICENSE, BSD 2-Clause, "Copyright (c) 2018 Python-MUMPS Authors".
# pyproject.toml also declares license: 'BSD-2-Clause' in the meson project().
License:        BSD-2-Clause
URL:            https://gitlab.kwant-project.org/kwant/python-mumps
Source0:        %{pypi_source python_mumps %{version} tar.gz}

# meson.build resolves MUMPS through pkg-config only, and Fedora's MUMPS ships
# no .pc files, so the build aborts although the library is installed. Adds a
# cc.find_library() fallback plus the mumps_common/pord/mpiseq pieces that
# pkg-config would have pulled in transitively.
Patch0:         python-mumps-find-library-fallback.patch

# Fedora's MUMPS is built for these; ExclusiveArch rather than BuildArch,
# which rpmlint rightly flags as the wrong tag for restricting architectures.
ExclusiveArch:  x86_64 aarch64

BuildRequires:  gcc
BuildRequires:  python3-devel
BuildRequires:  python3-Cython >= 3.1.1
BuildRequires:  python3-numpy >= 2.0
BuildRequires:  python3-scipy
BuildRequires:  python3-setuptools_scm
BuildRequires:  pyproject-rpm-macros
BuildRequires:  python3-meson-python
BuildRequires:  meson >= 1.1.0
BuildRequires:  ninja-build
BuildRequires:  MUMPS-devel
BuildRequires:  openblas-devel
BuildRequires:  python3-pytest

%global _description %{expand:
Python bindings and a scipy-friendly interface to MUMPS, the MUltifrontal
Massively Parallel sparse direct Solver. MUMPS factorises large sparse
matrices and is a good fit for the linear systems that come out of finite
element discretisations, where iterative solvers struggle with
ill-conditioning.

This is the sequential build against Fedora's MUMPS.}

%description %_description

%package -n python3-%{mod_name}
Summary:        %{summary}
Requires:       MUMPS

%description -n python3-%{mod_name} %_description

%prep
%autosetup -p1 -n python_mumps-%{version}

# setuptools_scm derives the version from git metadata, which an sdist has
# none of; meson calls it with check: true, so it fails the configure step.
# Pin the version from the tarball instead.
sed -i "s|version: run_command('python3', '-m', 'setuptools_scm', check: true).stdout().strip(),|version: '%{version}',|" \
    meson.build

%generate_buildrequires
# meson-python cannot produce metadata before the build, so read the deps
# from the [project] table instead (the -p flag).
%pyproject_buildrequires -p

%build
%pyproject_wheel

%install
%pyproject_install
%pyproject_save_files %{mod_name}

%check
%pyproject_check_import

# An import proves it linked; solving proves it works. MUMPS is a numerical
# library, so factorise a small system and check the answer. The API is
# Context.factor/.solve -- the same calls SimNIBS's fem.py makes
# (self.ctx = mumps.Context()) -- and the class documents complex support
# only, so the test uses a complex matrix as upstream's own docstring does.
PYTHONPATH=%{buildroot}%{python3_sitearch} %{python3} - <<'EOF'
import numpy as np
import scipy.sparse as sp
import mumps

A = sp.coo_array(np.array([[4.0, 1.0, 0.0],
                           [1.0, 3.0, 1.0],
                           [0.0, 1.0, 2.0]], dtype=complex))
x_exact = np.array([1.0, -2.0, 3.0], dtype=complex)
b = A.toarray() @ x_exact

ctx = mumps.Context()
ctx.factor(A)
x = ctx.solve(b)
assert np.allclose(x, x_exact, rtol=1e-10, atol=1e-12), (x, x_exact)

# One factorisation, several right-hand sides: the pattern a FEM solver uses.
rhs2 = A.toarray() @ np.ones(3, dtype=complex)
assert np.allclose(ctx.solve(rhs2), np.ones(3), rtol=1e-10, atol=1e-12)

print("mumps: factor/solve agrees with the exact solution to 1e-10")
EOF

%files -n python3-%{mod_name} -f %{pyproject_files}
%license LICENSE
%doc README.md AUTHORS.md

%changelog
* Sat Sep 26 2026 Morgan Hough <morgan.hough@gmail.com> - 0.0.6-1
- Initial package. simnibs/simulation/fem.py imports it at module scope, so
  `import simnibs` cannot succeed without it. Patched to find Fedora's MUMPS,
  which ships no pkg-config files.