#include <math.h>

#include "histogram.h"

#include "tcl_interface.h"

void Histogram::initialize_mean()

{

  int total_weight = 0;

  int i;

  for(i = 0; i < num_rows; i++)

    {

      total_weight = total_weight + row_weights[i];

    }

  mean = (double) total_weight / (double) num_rows;

}

inline double sqr(double x) {return(x*x);}

void Histogram::initialize_variance()

{ 

  double sum = 0;

  for(int i = 0; i < num_rows; i++)

      {

	sum += sqr(row_weights[i] - mean);

      }

  variance = (double) sum / (double) num_rows;

}

void Histogram::initialize_standard_dev()

{

  standard_dev = sqrt(variance);

}

#define SKIP 5

/* should get this skip from project.cc (!!) */

Histogram::display()

{

#if 0

  docommand(".histogram.c delete hist");

  docommand(".histogram.c create text 275 300 -font -adobe-helvetica-medium-o-normal--34-240-100-100-p-176-iso8859-1 -text \"%.3lf degrees, SD = %.3lf\" -tags hist", cut_angle, standard_dev);

  for(int i = 0; i < num_rows; i++)

      {

	docommand(".histogram.c create line 0 %d %d %d -fill blue -tags {hist} -width %d", i*SKIP, row_weights[i], i*SKIP, SKIP);

      }

  docommand("update");

#endif

}

Histogram::Histogram(int n_rows, int* r_weights, double c_angle)

{

  num_rows = n_rows;

  row_weights = r_weights;

  cut_angle = c_angle;

  initialize_mean();

  initialize_variance();

  initialize_standard_dev();

}

double find_int_sd(int* values, int num_values)

/* find the standard deviation of an array of ints */

{

  int total_weight = 0;

  int i;

  for(i = 0; i < num_values; i++)

    {

      total_weight = total_weight + values[i];

    }

  double mean_weight = (double) total_weight / (double) num_values;

  double standard_sum = 0;

  for(i = 0; i < num_values; i++)

    {

      standard_sum += sqr(values[i] - mean_weight);

    }

  standard_sum = standard_sum / (double) num_values;

  return sqrt(standard_sum);

}