histogram.h

/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2021 Peter W. Draper (p.w.draper@durham.ac.uk)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser 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 Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#ifndef SWIFT_HISTOGRAM_H
#define SWIFT_HISTOGRAM_H

/*  Bins in a histogram. Note this must be an even number. */
#define NHIST 65536

/**  Histogram structure. */
struct histogram {
  /* Raw histogram. NHIST counts in hist and the value associated with a bin
   * is index*width+zero. */
  double width;
  double zero;
  int hist[NHIST];

  /* Normalized cumulative histogram. Empty bins are joined into a larger one,
   * so values are the bin centre, sums the sum to that bin and nvalues the
   * number of bins that have been populated, can be less than NHIST. */
  double values[NHIST];
  double sums[NHIST];
  int nvalues;
};

int histread(const char *file, double **values, int *nvalues);
void histmake(int nvalues, double *values, struct histogram *h);

#endif