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Wrap Reference BLAS with PRIK

Build the complete Reference BLAS once, wrap it with PRIK and NumPy f2py, and compare both Python APIs with 155 named correctness tests.

All 155 routines are exported and validated through both wrappers, with no unsupported or skipped routines. The tests use small independent formulas and storage checks, so the comparison does not depend on either wrapper as its sole oracle.

Requirements

Install GNU Fortran. On Ubuntu:

sudo apt-get update
sudo apt-get install --yes gfortran

Install the pinned Python build tools:

python3 -m pip install "numpy==2.5.1" "meson==1.11.2" "ninja==1.13.0" pytest

Run the remaining commands from the repository root.

Quick start

Build both wrappers and run the complete comparison:

source examples/blas/build_all.sh
python3 -m pytest -q examples/blas/tests

Use source so the build paths exported by build_all.sh remain available to the test process.

How the build works

The native sources are compiled once into a shared library. PRIK reads the complete source tree to generate its Python API, skips native source compilation, and links that library. f2py compiles the committed reviewed blas.pyf and links the same library.

build_all.sh runs the following two scripts. The commands are shown so you can reuse or adapt either build independently.

Build the PRIK wrapper

export EXAMPLE_WORKSPACE="$PWD"
export BLAS_BUILD_ROOT="$(mktemp -d)"
export BLAS_SHARED_LIBRARY="$(
  python -m examples.native_library blas \
    --compiler "$(command -v gfortran)" \
    --jobs 8
)"

mkdir -p "$BLAS_BUILD_ROOT/prik/generated"
cd "$BLAS_BUILD_ROOT/prik"

python -m prik "$EXAMPLE_WORKSPACE/examples/blas/native" \
  --out prik_reference_blas \
  --out-dir "$BLAS_BUILD_ROOT/prik/generated" \
  --compiler "$(command -v gfortran)" \
  --no-compile-input-sources \
  --native-objects "$BLAS_SHARED_LIBRARY" \
  --jobs 8 \
  --wrapper-fortran-flags="-O0 -g0" \
  --wrapper-c-flags="-O0 -g0"

Build the f2py comparison wrapper

cd "$EXAMPLE_WORKSPACE"
export BLAS_F2PY_ROOT="$BLAS_BUILD_ROOT/f2py"
mkdir -p "$BLAS_F2PY_ROOT/generated"
cd "$BLAS_F2PY_ROOT"

export FC="$(command -v gfortran)"
export F77="$FC"
export F90="$FC"
export FFLAGS="-O0"
export F90FLAGS="-O0"
export LDFLAGS="${LDFLAGS:+$LDFLAGS }-Wl,-rpath,$(dirname "$BLAS_SHARED_LIBRARY")"

python -m numpy.f2py -c \
  "$EXAMPLE_WORKSPACE/examples/blas/blas.pyf" \
  "-L$(dirname "$BLAS_SHARED_LIBRARY")" \
  -lprik_full_blas \
  --build-dir "$BLAS_F2PY_ROOT/generated" \
  --f77flags=-O0 \
  --f90flags=-O0 \
  --opt=-O0

Run focused tests

After the quick-start build, run one family or routine:

python3 -m pytest -q examples/blas/tests/test_level1_real.py
python3 -m pytest -q \
  examples/blas/tests/test_level1_real.py::test_daxpy
python3 -m pytest -q examples/blas/tests -k dgemm

What is validated

PRIK preserves the native BLAS argument order and returns visible scalar writebacks.

The 6 rotation routines omit Fortran intent for scalar writebacks. blas.pyf records them as intent(inout), so f2py receives typed NumPy 0-D arrays. PRIK returns the same writebacks directly.

The tests cover positive and negative increments, leading-dimension padding, packed and banded layouts, triangular and Hermitian storage, native one-based indexes, input preservation, and dtype-aware numerical tolerances. The independent formula or invariant remains visible beside each wrapper call.

Sources and license

native/ contains the 155 files from BLAS/SRC/ in Netlib LAPACK 3.12.1. The audited archive has SHA-256 37b00c90947488521f475b5a187fff4da4a5cfe61b525efcacf7a97f39a45ec6. See the Netlib BLAS FAQ and the LAPACK license before redistributing the native sources.