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/* $Id: plhist.c,v 1.2 2007/05/08 09:09:37 rice Exp $
Histogram plotter.
Copyright (C) 2004 Alan W. Irwin
This file is part of PLplot.
PLplot is free software; you can redistribute it and/or modify
it under the terms of the GNU General Library Public License as published
by the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
PLplot 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 Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with PLplot; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "plplotP.h"
/*----------------------------------------------------------------------*\
* void plhist()
*
* Draws a histogram of n values of a variable in array data[0..n-1] in
* the range datmin to datmax using nbin bins. If "flags"'s first bit is 1, the
* histogram is plotted in the current window. If not, the routine calls
* "plenv" to set up the graphics environment.
*
* If flags's second bit is set, then items which fall outside the bin
* range are ignored.
*
* If flags's third bit is set, the outside bars are the same size
* as the rest. The default old behaviour was for the first and last
* bars to expand visually to fill the entire available space.
\*----------------------------------------------------------------------*/
void
c_plhist(PLINT n, PLFLT *data, PLFLT datmin, PLFLT datmax,
PLINT nbin, PLINT flags)
{
PLINT i, bin;
PLFLT *x, *y, dx, ymax;
if (plsc->level < 1) {
plabort("plhist: Please call plinit first");
return;
}
if (plsc->level < 3 && (flags & 1)) {
plabort("plhist: Please set up window first");
return;
}
if (datmin >= datmax) {
plabort("plhist: Data range invalid");
return;
}
if ( ! (x = (PLFLT *) malloc((size_t) nbin * sizeof(PLFLT)))) {
plabort("plhist: Out of memory");
return;
}
if ( ! (y = (PLFLT *) malloc((size_t) nbin * sizeof(PLFLT)))) {
free((void *) x);
plabort("plhist: Out of memory");
return;
}
dx = (datmax - datmin) / nbin;
for (i = 0; i < nbin; i++) {
x[i] = datmin + i * dx;
y[i] = 0.0;
}
for (i = 0; i < n; i++) {
bin = (data[i] - datmin) / dx;
if ((flags & 2) == 0) {
bin = bin > 0 ? bin : 0;
bin = bin < nbin ? bin : nbin - 1;
y[bin]++;
} else {
if(bin >= 0 && bin < nbin) {
y[bin]++;
}
}
}
if (!(flags & 1)) {
ymax = 0.0;
for (i = 0; i < nbin; i++)
ymax = MAX(ymax, y[i]);
plenv(datmin, datmax, (PLFLT) 0.0, (PLFLT) (1.1 * ymax), 0, 0);
}
/* We pass on the highest couple of bits to the 'plbin' routine */
plbin(nbin, x, y, (flags & (4+8+16+32)) >> 2);
free((void *) x);
free((void *) y);
}
/*----------------------------------------------------------------------*\
* void plbin()
*
* Plot a histogram using the arrays x and y to represent data values
* and frequencies respectively. If flags first bit is false, x values
* denote the lower edge of the bin, and if it is true, they denote
* the center of the bin. If flags second bit is true, then we assume
* the edge bins are the same size as the rest (i.e. the edge bins
* needn't go as far as the variables vpwxmi, vpwxma below).
\*----------------------------------------------------------------------*/
void
c_plbin(PLINT nbin, PLFLT *x, PLFLT *y, PLINT flags)
{
PLINT i;
PLFLT xmin, xmax, vpwxmi, vpwxma, vpwymi, vpwyma;
if (plsc->level < 3) {
plabort("plbin: Please set up window first");
return;
}
/* Check x[i] are in ascending order */
for (i = 0; i < nbin - 1; i++) {
if (x[i] >= x[i + 1]) {
plabort("plbin: Elements of x array must be increasing");
return;
}
}
plgvpw(&vpwxmi, &vpwxma, &vpwymi, &vpwyma);
if (!(flags & 1)) {
for (i = 0; i < nbin - 1; i++) {
if (!(flags & 4) || (y[i] != vpwymi)) {
pljoin(x[i], vpwymi, x[i], y[i]);
pljoin(x[i], y[i], x[i + 1], y[i]);
pljoin(x[i + 1], y[i], x[i + 1], vpwymi);
}
}
if (flags & 2) {
if (!(flags & 4) || (y[i] != vpwymi)) {
int xm = x[i] + (x[i] - x[i-1]);
pljoin(x[i], vpwymi, x[i], y[i]);
pljoin(x[i], y[i], xm, y[i]);
pljoin(xm, y[i], xm, vpwymi);
}
} else {
if (x[i] < vpwxma) {
if (!(flags & 4) || (y[i] != vpwymi)) {
pljoin(x[i], vpwymi, x[i], y[i]);
pljoin(x[i], y[i], vpwxma, y[i]);
pljoin(vpwxma, y[i], vpwxma, vpwymi);
}
}
}
} else {
if (nbin < 2)
return;
if (flags & 2) {
xmin = MAX(vpwxmi, 0.5 * (3 * x[0] - x[1]));
} else {
xmin = vpwxmi;
}
/* Vince fixed bug May 1998 */
xmax = MAX(0.5 * (x[0] + x[1]), vpwxmi);
if (xmin < xmax) {
pljoin(xmin, vpwymi, xmin, y[0]);
pljoin(xmin, y[0], xmax, y[0]);
pljoin(xmax, y[0], xmax, vpwymi);
}
for (i = 1; i < nbin - 1; i++) {
xmin = xmax;
xmax = MIN(0.5 * (x[i] + x[i + 1]), vpwxma);
if (!(flags & 4) || (y[i] != vpwymi)) {
pljoin(xmin, vpwymi, xmin, y[i]);
pljoin(xmin, y[i], xmax, y[i]);
pljoin(xmax, y[i], xmax, vpwymi);
}
}
xmin = xmax;
xmax = vpwxma;
if (flags & 2) {
xmax = MIN(vpwxma, 0.5 * (3 * x[i] - x[i-1]));
} else {
xmax = vpwxma;
}
if (xmin < xmax) {
if (!(flags & 4) || (y[i] != vpwymi)) {
pljoin(xmin, vpwymi, xmin, y[i]);
pljoin(xmin, y[i], xmax, y[i]);
pljoin(xmax, y[i], xmax, vpwymi);
}
}
}
}
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