Overview#

The MUSICA-Fortran interface exposes the MUSICA C++ library to Fortran programs via the Fortran-C interoperability features of iso_c_binding. For installation, see Fortran.

The tutorials below progress from printing the MICM version through running a multi-grid-cell box model. Each section follows the same pattern:

  • Defining a Mechanism — load a mechanism configuration file directory

  • Creating a Solver — instantiate micm_t with a config path and solver type

  • Setting Conditions — populate the state concentrations and environmental parameters

  • Solving — call micm%solve at each time step

  • Accessing Results — read updated concentrations from the state array

Note

TUV-x photolysis and CARMA aerosol support are not yet available in the Fortran API.

Fortran-C Interoperability#

MUSICA’s Fortran API is built on the standard iso_c_binding module. Here is a minimal example showing how a C function can be called from Fortran, which is the same mechanism underlying all MUSICA Fortran bindings:

#include <stdio.h>

void test_proc_c(int n, double A[3][2]) {
    printf("n = %d\n", n);
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 3; j++) printf("%6.2f ", A[j][i]);
        printf("\n");
    }
}

program demo_fort
    use iso_c_binding, only: c_int, c_double
    implicit none
    integer(c_int) :: n_fort = 7
    real(c_double), dimension(2, 3) :: A_fort
    interface
        subroutine test_proc_c(n_c, A_c) bind(C, name='test_proc_c')
            use iso_c_binding, only: c_int, c_double
            integer(c_int), intent(in), value :: n_c
            real(c_double), dimension(2, 3), intent(in) :: A_c
        end subroutine test_proc_c
    end interface
    integer :: i, j
    do j = 1, 3
        do i = 1, 2
            A_fort(i, j) = real(i + j, c_double)
        end do
    end do
    call test_proc_c(n_fort, A_fort)
end program demo_fort

Tutorials: