/* tools.c: a collection for routines to provide timing and random numbers.
 * The timer returns execution time in fractional
 * seconds.  Integer and floating point random number generators are
 * provided.  Routines are also included to initialize the timer and random
 * number generators.
 *
 * The routine which initializes the random number generator takes a 
 * single integer argument; if this argument <= zero, the seed
 * is initialized from the CPU clock; a positive argument is used
 * directly as the seed.
 *
 * G. S. Stiles; 25 Aug. 1993.
 * Modified from timers.c to include the improved random number
 * generator from Park & Miller, CACM Oct. 1988. (Actually their later
 * improved version, as available via FTP...see CACM July 1993, pp. 105-
 * 110.  The period of the generator is 2 147 483 646. The package will
 * provide 256 different streams. The default is stream 0; others may be
 * selected with the function Select_Stream(stream_no). The seeds for the
 * streams are separated by 8 367 782 steps.  See rngs.c for details.)
 *
 * The largest random integer which can be generated is 2 147 483 646.
 */

/* for the use mit GNU C-Compiler*/
#define GNUC

#include <stdlib.h>
#include <my_math.h>

#include "parrandom.h"

#define MIN(x,y) ( (x < y) ? x : y)
#define MAX(x,y) ((x > y) ? x : y)
 
void moments(int    samples, float  *sumx, float *sumy)

{
  if (samples > 0){
    *sumx = *sumx/samples;
    if (samples > 1){
      *sumy = (*sumy - samples*(*sumx)*(*sumx))/(samples - 1);
      if (*sumy > 0.0) *sumy = sqrt(*sumy); 
      else *sumy = 0.0;
    }
    else *sumy = 0.0;
  }
  else {
    *sumx = 0.0;
    *sumy = 0.0;
  }
}
void Dmoments(int samples, double  *sumx, double *sumy)

{
  if (samples > 0){
    *sumx = *sumx/samples;
    if (samples > 1){
      *sumy = (*sumy - samples*(*sumx)*(*sumx))/(samples - 1);
      if (*sumy > 0.0) *sumy = sqrt(*sumy); 
      else *sumy = 0.0;
    }
    else *sumy = 0.0;
  }
  else {
    *sumx = 0.0;
    *sumy = 0.0;
  }
}



/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*
 * GNU C versions.
 *
 */
#include <time.h>
#include <sys/times.h>
#include <string.h>
/*#include <values.h>*/

/* Static variables: */
long   INITIAL_TIME;
/*
 * init_time:  initialize the execution timer.
 *
 */
void init_time()
{
  struct  tms *timebuf;

  timebuf = (struct tms *)malloc(sizeof(struct tms));

  times(timebuf);
  INITIAL_TIME = timebuf->tms_utime;
}
/*
 * get_time: returns time in float seconds elapsed since call to init_time;
 *
 */
float get_time()
{
  float  temp;
  long this_time;
  struct  tms *timebuf;

  timebuf = (struct tms *)malloc(sizeof(struct tms));
  times(timebuf);
  this_time = timebuf->tms_utime;

  temp = ((float)(this_time - INITIAL_TIME))/60.0;

  return(temp);
}

void get_datime(char *str_out)

 {
   /*
    * Date and time stamper; stolen from Turbo C manual.
    * Dyke Stiles; 3/31/91
    * This version places a string containing the time and date
    * in str_out.  GSS; 2/15/92. The destination string in the calling
    * program (str_now) should be declared with a length of [25].
    *
    */

  time_t  secs_now;
  char    *str_now;

  /* Get the time in seconds:  */
  time(&secs_now);

  /* Convert to string: */
  str_now = ctime(&secs_now);

  /*Get rid of the carriage return: */
  str_now[24] = '\0';
  strncpy(str_out,str_now,25);
 }

/*
 * init_rand initializes the random number generator.
 */
void init_rand(int new_seed)
{
  int i_temp;

  if (new_seed <= 0){
    i_temp = time(0);
    Randomize(i_temp);
  }
  else{
    Randomize(new_seed);
  }
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*
 *  Common routines
 *
 */

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/
/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * rand_int returns a random integer in the range [0,limit).
 * Note that Select_Stream must first be called to set the correct
 * stream.
 *
 */
int rand_int(int limit)
{
  long int   i_temp;
  float f_temp;

  /* Modified to work with rngs.c, which does not supply an explicit
   * integer random number.
   */
  
  /* Call for rngs float first so that new integer seed is generated: */
  f_temp = Random();

  Get_Seed(&i_temp);
  i_temp = i_temp % limit;

  return(i_temp);
}

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * rand_float returns a random floating point number in the range [0,1);
 *
 */
float rand_float()
{
  return((float) Random());
}
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * rand16_float returns a random floating point number in the range [0,1);
 * The random number is based on 16 bit integers.
 */
float rand16_float()
{
  int temp1;

  temp1 = rand_int(32767);
  return((float) temp1/((float)32767));
}
     
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++      
 * rand8_float returns a random floating point number in the range [0,1);      
 * The random number is based on 16 bit integers.                               
 */                                                                             
float rand8_float()                                                            
{                                                                               
  int temp1;                                                                    

  temp1 = rand_int(255);                                                      
  return((float) temp1/((float)255));                                         
}

      
/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 * rand64_float returns a random floating point number generated from
 * a (equivalent) 64 bit integer.  Sort of.
 
float rand64_float()
{
  int offset;
  double temp1;


long int s;
Get_Seed(&s);

  temp1= Random();

  offset = rand_int(20) + 1;
  Select_Stream(s + offset);

  temp1 = temp1 + Random()/((double)MAXINT);

  Select_Stream(s - offset);
  return((float) temp1 );
}
*/
/*+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 *
 * rand64_double() returns a random double precision floating point
 * number generated from essentially a 64-bit integer.
 
double rand64_double()
{
  return(Random() + Random()/((double) MAXINT));
}
*/

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 * rand_double returns a random double floating point number in [0,1);
 *
 */
double rand_double()
{
  return(Random());
}