#include "ezinc.h"

static double cdtds, ppw = 0;

/* initialize source-function variables */
void ezIncInit(Grid *g){

  printf("Enter the points per wavelength for Ricker source: ");
  scanf(" %lf", &ppw);
  cdtds = Cdtds;   
  return;
}

/* calculate source function at given time and location */
double ezInc(double time, double location) {
  double arg;

  if (ppw <= 0) {
    fprintf(stderr,
       "ezInc: ezIncInit() must be called before ezInc.\n"
       "       Points per wavelength must be positive.\n");
    exit(-1);
  }

  arg = M_PI * ((cdtds * time - location) / ppw - 1.0);
  arg = arg * arg;

  return (1.0 - 2.0 * arg) * exp(-arg);
}