This is a Modern Fortran interface for the LSODA and LSODAR routines in ODEPACK, which is for solving ordinary differential equation initial value problems. This repository contains a modified version of ODEPACK which is threadsafe.

For a simple example see test/test_lsoda.f90

CMake

mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
cmake --build .
# run tests
./test/test_lsoda
./test/test_threadsafe
# run benchmark
./test/benchmark

Add as a dependency to your CMake projects with the CMake Package Manager

Fortran Package Manager

fpm build --profile release
fpm test --profile release

The file src/odepack_mod.f90 contains extensive comments describing the use of the user-interfacing class lsoda_class.

• This repository replaces common blocks with a passed derived type. This makes the code threadsafe.
• The code now attempts to link to optimized linear algebra routines (e.g. OpenBLAS). If, e.g. OpenBLAS, is not found on the system, then compilation falls back on LAPACK routines downloaded from netlib. This replaces the old LINPACK routines that came with the original version of ODEPACK.
• This repository changes the interface to the ODE right-hand-side subroutine, the jacobian and the root-finding subroutine, by adding a ierr argument. If ierr is set to less than 0 in these subroutines, then the integration is gracefully terminated.
• Root-finding now indicates the direction of the root. See variable jroot in src/odepack_mod.f90
• LSODA no longer prints fatal error messages. Error messages are stored in a string which the user can access and print if they like. See error_message in src/odepack_mod.f90.