Call Python Function From Fortran/c

I am writing a Fortran code and I would like to use some special functions and methods from Python libraries. This is a Python code: from mpmath import * from scipy.optimize import

Solution 1:

SOLUTION

In case someone is interested I have solved this problem. The following was of great help: stackoverflow and yolinux.

rootC.c

#include"rootC.h"#include<Python.h>#include<stdlib.h>voidInitialize(){
    Py_Initialize();
}

voidFinalize(){
    Py_Finalize();
}

voidroot_(double* A, double* B, double* t, double* x){
    PyObject *pName, *pModule, *pFunc;
    PyObject *pArgs, *pValue, *sys, *path;
    staticint i;

    if (i == 0)
    {    
        ++i;
        Initialize();
        atexit(Finalize);
    }

    sys  = PyImport_ImportModule("sys");
    path = PyObject_GetAttrString(sys, "path");
    PyList_Append(path, PyString_FromString("."));

    pName = PyString_FromString("rootPY");
    pModule = PyImport_Import(pName);

    if (!pModule)
    {
        PyErr_Print();
        printf("ERROR in pModule\n");
        exit(1);
    }

    pFunc = PyObject_GetAttrString(pModule, "root");
    pArgs = PyTuple_New(3);
    PyTuple_SetItem(pArgs, 0, PyFloat_FromDouble((*A)));
    PyTuple_SetItem(pArgs, 1, PyFloat_FromDouble((*B)));
    PyTuple_SetItem(pArgs, 2, PyFloat_FromDouble((*t)));
    
    pValue = PyObject_CallObject(pFunc, pArgs);
    *x     = PyFloat_AsDouble(pValue);
}

rootC.h

#ifndef ROOT_H_#define ROOT_H_voidInitialize();
voidFinalize();
voidroot_(double*, double*, double*, double*);

#endif

rootPY.py

from mpmath import polylog, exp
from scipy.optimize import newton

defroot(A,B,t):   
    returnabs(newton(lambda x: (x - A*polylog(1.5, B*exp(-t*x))), 0.0))

rootF.F90

program main
   implicit none
   real*8 A, B, t, xA=0.4d0B=0.3d0t=0.1d0

   call root(A,B,t,x)

   write(*,*) x

end program main

main.c

#include"rootC.h"#include<stdio.h>intmain(){
    double A = 0.4, B = 0.3, t = 0.1, x = 0.0;

    root_(&A,&B,&t,&x);

    printf("A = %f, B = %f, t = %f\n", A, B, t);

    printf("x = %.15f\n", x);

    return0;
}

Makefile

CC = gcc
FC = gfortran
CFLAGS = -I/usr/include/python2.7
LFLAGS = -L/usr/local/lib -lpython2.7 -lm

.PHONY: all cleanall: rootF mainrootF: rootF.o rootC.o$(FC)$^ -o $@$(LFLAGS)rootF.o: rootF.F90$(FC) -c $< -o $@main: main.o rootC.o$(CC)$^ -o $@$(LFLAGS)main.o: main.c$(CC)$(CFLAGS) -c $< -o $@rootC.o: rootC.c$(CC)$(CFLAGS) -c $< -o $@clean:
    rm -f *.o