#include <math.h>
#include "fdtd-macro-tmz.h"
#include "fdtd-alloc1.h"

#define NLOSS     20   // number of lossy cells at end of 1D grid
#define MAX_LOSS  0.35 // maximum loss factor in lossy layer 

void gridInit1d(Grid *g) {
  double imp0 = 377.0, depthInLayer, lossFactor;
  int mm;

  SizeX += NLOSS;    // size of domain   
  Type = oneDGrid;   // set grid type    

  ALLOC_1D(g->hy,   SizeX - 1, double);  
  ALLOC_1D(g->chyh, SizeX - 1, double);
  ALLOC_1D(g->chye, SizeX - 1, double);
  ALLOC_1D(g->ez,   SizeX, double);
  ALLOC_1D(g->ceze, SizeX, double);
  ALLOC_1D(g->cezh, SizeX, double);     
  
  /* set the electric- and magnetic-field update coefficients */
  for (mm = 0; mm < SizeX - 1; mm++) {  
    if (mm < SizeX - 1 - NLOSS) {
      Ceze1(mm) = 1.0;
      Cezh1(mm) = Cdtds * imp0;
      Chyh1(mm) = 1.0;
      Chye1(mm) = Cdtds / imp0;
    } else {
      depthInLayer = mm - (SizeX - 1 - NLOSS) + 0.5;
      lossFactor = MAX_LOSS * pow(depthInLayer / NLOSS, 2);
      Ceze1(mm) = (1.0 - lossFactor) / (1.0 + lossFactor);
      Cezh1(mm) = Cdtds * imp0 / (1.0 + lossFactor);
      depthInLayer += 0.5;
      lossFactor = MAX_LOSS * pow(depthInLayer / NLOSS, 2);
      Chyh1(mm) = (1.0 - lossFactor) / (1.0 + lossFactor);
      Chye1(mm) = Cdtds / imp0 / (1.0 + lossFactor);
    }
  }

  return;
}