# include <stdio.h>
# include <stdlib.h>
# include <string.h>
# include <time.h>

# include "flame_exact.h"

int main ( );
double *r8vec_linspace_new ( int n, double a, double b );
void timestamp ( );

/******************************************************************************/

int main ( )

/******************************************************************************/
/*
  Purpose:

    flame_exact_test() tests flame_exact().

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    29 April 2024

  Author:

    John Burkardt
*/
{
  int r = 4;
  int n = 101;

  char command_filename[255];
  FILE *command_unit;
  char data_filename[255];
  FILE *data_unit;
  char *header = "flame_exact";
  int i;
  int j;
  double *t;
  double t0;
  double tstop;
  double *y;
  double y0;
  static double y0_vec[4] = { 0.005, 0.01, 0.02, 0.05 };

  timestamp ( );
  printf ( "\n" );
  printf ( "flame_exact_test():\n" );
  printf ( "  C version\n" );
  printf ( "  flame_exact() evaluates the exact solution of the flame ODE.\n" );
/*
  Get parameters.
*/
  flame_parameters ( NULL, NULL, NULL, &t0, &y0, &tstop );
/*
  Extend time interval.
*/
  tstop = 300.0;
  flame_parameters ( NULL, NULL, &tstop, NULL, NULL, NULL );

  printf ( "\n" );
  printf ( "  parameters:\n" );
  printf ( "    t0    = %g\n", t0 );
  printf ( "    tstop = %g\n", tstop );
/*
  Compute (t,y) pairs for n times, and r values of y0.
*/
  t = r8vec_linspace_new ( n, t0, tstop );
  y = ( double * ) malloc ( n * r * sizeof ( double ) );

  for ( j = 0; j < r; j++ )
  {
    y0 = y0_vec[j];
    printf ( "    y0 = %g\n", y0 );
    flame_parameters ( NULL, &y0, NULL, NULL, NULL, NULL );
    flame_exact ( n, t, y + n*j );
  }
/*
  Create the data file.
*/
  strcpy ( data_filename, header );
  strcat ( data_filename, "_data.txt" );
  data_unit = fopen ( data_filename, "wt" );

  for ( i = 0; i < n; i++ )
  {
    fprintf ( data_unit, "%g", t[i] );
    for ( j = 0; j < r; j++ )
    {
      fprintf ( data_unit, "  %g", y[i+j*n] );
    }
    fprintf ( data_unit, "\n" );
  }

  fclose ( data_unit );
  printf ( "\n" );
  printf ( "  Data stored in '%s'\n", data_filename );
/*
  Create the command file.
*/
  strcpy ( command_filename, header );
  strcat ( command_filename, "_commands.txt" );
  command_unit = fopen ( command_filename, "wt" );

  fprintf ( command_unit, "# %s\n", command_filename );
  fprintf ( command_unit, "#\n" );
  fprintf ( command_unit, "# Usage:\n" );
  fprintf ( command_unit, "#  gnuplot < %s\n", command_filename );
  fprintf ( command_unit, "#\n" );
  fprintf ( command_unit, "set term png\n" );
  fprintf ( command_unit, "set output '%s.png'\n", header );
  fprintf ( command_unit, "set xlabel '<-- t -->'\n" );
  fprintf ( command_unit, "set ylabel '<-- y(t) -->'\n" );
  fprintf ( command_unit, "set title 'flame_exact:'\n" );
  fprintf ( command_unit, "set grid\n" );
  fprintf ( command_unit, "set style data lines\n" );
  fprintf ( command_unit, "plot '%s' using 1:2 with lines lw 3,\\\n", data_filename );
  fprintf ( command_unit, "     '%s' using 1:3 with lines lw 3,\\\n", data_filename );
  fprintf ( command_unit, "     '%s' using 1:4 with lines lw 3,\\\n", data_filename );
  fprintf ( command_unit, "     '%s' using 1:5 with lines lw 3\n", data_filename );
  fprintf ( command_unit, "quit\n" );

  fclose ( command_unit );

  printf ( "  Plot commands stored in '%s'\n", command_filename );
/*
  Free memory.
*/
  free ( t );
  free ( y );
/*
  Terminate.
*/
  printf ( "\n" );
  printf ( "flame_exact_test():\n" );
  printf ( "  Normal end of execution.\n" );
  printf ( "\n" );
  timestamp ( );

  return 0;
}
/******************************************************************************/

double *r8vec_linspace_new ( int n, double a, double b )

/******************************************************************************/
/*
  Purpose:

    r8vec_linspace_new() creates a vector of linearly spaced values.

  Discussion:

    An R8VEC is a vector of R8's.

    4 points evenly spaced between 0 and 12 will yield 0, 4, 8, 12.
 
    In other words, the interval is divided into N-1 even subintervals,
    and the endpoints of intervals are used as the points.

  Licensing:

    This code is distributed under the MIT license.

  Modified:

    29 March 2011

  Author:

    John Burkardt

  Input:

    int N, the number of entries in the vector.

    double A, B, the first and last entries.

  Output:

    double R8VEC_LINSPACE_NEW[N], a vector of linearly spaced data.
*/
{
  int i;
  double *x;

  x = ( double * ) malloc ( n * sizeof ( double ) );

  if ( n == 1 )
  {
    x[0] = ( a + b ) / 2.0;
  }
  else
  {
    for ( i = 0; i < n; i++ )
    {
      x[i] = ( ( double ) ( n - 1 - i ) * a 
             + ( double ) (         i ) * b ) 
             / ( double ) ( n - 1     );
    }
  }
  return x;
}
/******************************************************************************/

void timestamp ( )

/******************************************************************************/
/*
  Purpose:

    timestamp() prints the current YMDHMS date as a time stamp.

  Example:

    17 June 2014 09:45:54 AM

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    01 May 2021

  Author:

    John Burkardt
*/
{
# define TIME_SIZE 40

  static char time_buffer[TIME_SIZE];
  const struct tm *tm;
  time_t now;

  now = time ( NULL );
  tm = localtime ( &now );

  strftime ( time_buffer, TIME_SIZE, "%d %B %Y %I:%M:%S %p", tm );

  printf ( "%s\n", time_buffer );

  return;
# undef TIME_SIZE
}