#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <math.h>

/* Include polybench common header. */
#include <polybench.h>

/* Include benchmark-specific header. */
/* Default data type is double, default size is 50x1000x1000. */
#include "fdtd-2d.h"

/* Array initialization. */
static void init_array(int tmax,
                       int nx,
                       int ny,
                       DATA_TYPE POLYBENCH_2D(ex, NX, NY, nx, ny),
                       DATA_TYPE POLYBENCH_2D(ey, NX, NY, nx, ny),
                       DATA_TYPE POLYBENCH_2D(hz, NX, NY, nx, ny),
                       DATA_TYPE POLYBENCH_1D(_fict_, TMAX, tmax))
{
  int i, j;

  for (i = 0; i < tmax; i++)
    _fict_[i] = (DATA_TYPE)i;
  for (i = 0; i < nx; i++)
    for (j = 0; j < ny; j++)
    {
      ex[i][j] = ((DATA_TYPE)i * (j + 1)) / nx;
      ey[i][j] = ((DATA_TYPE)i * (j + 2)) / ny;
      hz[i][j] = ((DATA_TYPE)i * (j + 3)) / nx;
    }
}

/* DCE code. Must scan the entire live-out data.
   Can be used also to check the correctness of the output. */
static void print_array(int nx,
                        int ny,
                        DATA_TYPE POLYBENCH_2D(ex, NX, NY, nx, ny),
                        DATA_TYPE POLYBENCH_2D(ey, NX, NY, nx, ny),
                        DATA_TYPE POLYBENCH_2D(hz, NX, NY, nx, ny))
{
  int i, j;

  for (i = 0; i < nx; i++)
    for (j = 0; j < ny; j++)
    {
      fprintf(stderr, DATA_PRINTF_MODIFIER, ex[i][j]);
      fprintf(stderr, DATA_PRINTF_MODIFIER, ey[i][j]);
      fprintf(stderr, DATA_PRINTF_MODIFIER, hz[i][j]);
      if ((i * nx + j) % 20 == 0)
        fprintf(stderr, "\n");
    }
  fprintf(stderr, "\n");
}

/* Main computational kernel. The whole function will be timed,
   including the call and return. */
static void kernel_fdtd_2d(int tmax,
                           int nx,
                           int ny,
                           DATA_TYPE POLYBENCH_2D(ex, NX, NY, nx, ny),
                           DATA_TYPE POLYBENCH_2D(ey, NX, NY, nx, ny),
                           DATA_TYPE POLYBENCH_2D(hz, NX, NY, nx, ny),
                           DATA_TYPE POLYBENCH_1D(_fict_, TMAX, tmax))
{
  int t, i, j;

  for (t = 0; t < _PB_TMAX; t++)
  {
    for (j = 0; j < _PB_NY; j++)
      ey[0][j] = _fict_[t];
    for (i = 1; i < _PB_NX; i++)
      for (j = 0; j < _PB_NY; j++)
        ey[i][j] = ey[i][j] - 0.5 * (hz[i][j] - hz[i - 1][j]);
    for (i = 0; i < _PB_NX; i++)
      for (j = 1; j < _PB_NY; j++)
        ex[i][j] = ex[i][j] - 0.5 * (hz[i][j] - hz[i][j - 1]);
    for (i = 0; i < _PB_NX - 1; i++)
      for (j = 0; j < _PB_NY - 1; j++)
        hz[i][j] = hz[i][j] - 0.7 * (ex[i][j + 1] - ex[i][j] + ey[i + 1][j] - ey[i][j]);
  }
}

int main(int argc, char **argv)
{
  /* Retrieve problem size. */
  int tmax = TMAX;
  int nx = NX;
  int ny = NY;

  /* Variable declaration/allocation. */
  POLYBENCH_2D_ARRAY_DECL(ex, DATA_TYPE, NX, NY, nx, ny);
  POLYBENCH_2D_ARRAY_DECL(ey, DATA_TYPE, NX, NY, nx, ny);
  POLYBENCH_2D_ARRAY_DECL(hz, DATA_TYPE, NX, NY, nx, ny);
  POLYBENCH_1D_ARRAY_DECL(_fict_, DATA_TYPE, TMAX, tmax);

  /* Initialize array(s). */
  init_array(tmax, nx, ny,
             POLYBENCH_ARRAY(ex),
             POLYBENCH_ARRAY(ey),
             POLYBENCH_ARRAY(hz),
             POLYBENCH_ARRAY(_fict_));

  /* Start timer. */
  polybench_start_instruments;

  /* Run kernel. */
  kernel_fdtd_2d(tmax, nx, ny,
                 POLYBENCH_ARRAY(ex),
                 POLYBENCH_ARRAY(ey),
                 POLYBENCH_ARRAY(hz),
                 POLYBENCH_ARRAY(_fict_));

  /* Stop and print timer. */
  polybench_stop_instruments;
  polybench_print_instruments;

  /* Prevent dead-code elimination. All live-out data must be printed
     by the function call in argument. */
  polybench_prevent_dce(print_array(nx, ny, POLYBENCH_ARRAY(ex),
                                    POLYBENCH_ARRAY(ey),
                                    POLYBENCH_ARRAY(hz)));

  /* Be clean. */
  POLYBENCH_FREE_ARRAY(ex);
  POLYBENCH_FREE_ARRAY(ey);
  POLYBENCH_FREE_ARRAY(hz);
  POLYBENCH_FREE_ARRAY(_fict_);

  return 0;
}