/*
# statistics.h: find the first and second moments.
#
# Copyright (C) 1992, 2011 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
*/


#ifndef STATISTICS_H
#define STATISTICS_H

#include "types.h"

typedef struct
{
  real mean;
  real variance;
} statistics_type;

/* Compute the statistics on A.  */
extern statistics_type statistics (real *a, unsigned length,
                                   unsigned pertinent);

/* Return the mean of the array A, assumed to have length LENGTH -- but
   only PERTINENT of the entries really count.  */
extern real mean (real *a, unsigned length, unsigned pertinent);

/* Similarly, for the standard deviation.  */
extern real standard_deviation (real *, real mean, unsigned length,
                                unsigned pertinent);

#endif /* not STATISTICS_H */