simulacion-permeabilidad/fftma_module/gen/lib_src/spherical.c

#include "genlib.h"
#include <math.h>
#include <stdio.h>

/*spherical covariance function*/
double spherical(double h) {
    double z;

    if (h >= 1.) {
        z = 0.;
    } else {
        z = 1. - 1.5 * (double)h + 0.5 * (double)(h * h * h);
    }
    
    return z;
}