/* ezInc2.c: Functions to calculate the source function (i.e., the
 * incident field). */ 

#include "ezInc2.h"  

/* global variables -- but private to this file */
static double delay, width = 0, cdtds;  

/* prompt user for source-function width and delay. */
void ezIncInit(Grid *g){

  cdtds = Cdtds;  
  printf("Enter temporal delay [number of time steps to peak]: ");
  scanf(" %lf", &delay);
  printf("Enter width [time steps between peak and 1/e]: ");
  scanf(" %lf", &width);

  return;
}

/* calculate source function at given time and location */
double ezInc(double time, double location) {
  if (width <= 0) {
    fprintf(stderr,
       "ezInc: must call ezIncInit before ezInc.\n"
       "       Width must be positive.\n");
    exit(-1);
  }
  return exp(-pow((time - delay - location / cdtds) / width, 2));
}