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

/*cardsin covariance function*/
double cardsin(double h)
{
    float delta = 20.371;
    double z;

    if (h != 0) {
        z = (double)(h * delta);
        z = sin(z) / z;
    } else {
        z = 1.;
    }
    return (z);
}