Pileus Git - ~andy/gtk/blob - tests/variable.c

   1 /* -*- mode: C; c-basic-offset: 2; indent-tabs-mode: nil; -*- */
   2
   3 #include <math.h>
   4 #include "variable.h"
   5
   6 void
   7 variable_add_weighted (Variable *variable,
   8                        double    value,
   9                        double    weight)
  10 {
  11   variable->weight += weight;
  12   variable->sum += weight * value;
  13   variable->sum2 += weight * value * value;
  14 }
  15
  16 void
  17 variable_add (Variable *variable,
  18               double    value)
  19 {
  20   variable_add_weighted (variable, value, 1.);
  21 }
  22
  23 double
  24 variable_mean (Variable *variable)
  25 {
  26   return variable->sum / variable->weight;
  27 }
  28
  29 double
  30 variable_standard_deviation (Variable *variable)
  31 {
  32   double mean = variable_mean (variable);
  33   return sqrt (variable->sum2 / variable->weight - mean * mean);
  34 }
  35
  36 void
  37 variable_reset (Variable *variable)
  38 {
  39   variable->weight = 0;
  40   variable->sum = 0;
  41   variable->sum2 = 0;
  42 }
  43