#!/bin/bash
# Build the fmm3dbie shared library that the reference backend loads through ctypes.
# Usage: scripts/build_fmm3dbie.sh [install_dir]   (default ~/src/fmm3dbie)
# Needs git, gfortran, make and an OpenBLAS (or other BLAS/LAPACK) library.
set -euo pipefail
DEST="${1:-$HOME/src/fmm3dbie}"
# The commit used for the results in the README; set FMM3DBIE_COMMIT= (empty) for the latest.
COMMIT="${FMM3DBIE_COMMIT-94cb732e1660f74864ef0f527ef713d308453d09}"
if [ ! -d "$DEST/.git" ]; then
    git clone https://github.com/fastalgorithms/fmm3dbie "$DEST"
fi
cd "$DEST"
if [ -n "$COMMIT" ]; then git checkout -q "$COMMIT"; fi
git submodule update --init
if [ ! -f make.inc ]; then
    cp make.inc.linux.gnu.openblas make.inc
    # Some systems ship only the versioned runtime library (libopenblas.so.0) without the
    # development link; link against it directly in that case.
    if ! ld -lopenblas -o /dev/null --unresolved-symbols=ignore-all 2>/dev/null; then
        for lib in /usr/lib64/libopenblas.so.0 /usr/lib/x86_64-linux-gnu/libopenblas.so.0; do
            if [ -f "$lib" ]; then sed -i "s|^LBLAS=.*|LBLAS=-l:libopenblas.so.0|" make.inc; break; fi
        done
    fi
fi
make lib -j"$(nproc)"
echo
echo "Built $DEST/lib/libfmm3dbie.so. If it is not at ~/src/fmm3dbie, set"
echo "    export FMM3DBIE_LIB=$DEST/lib/libfmm3dbie.so"