acc (struct statistic *s, const struct ccase *cx UNUSED, double c, double cc UNUSED, double y)
{
struct histogram *hist = UP_CAST (s, struct histogram, parent);
- gsl_histogram *gslh = hist->gsl_hist;
- /* Include cases which are just on the boundary */
- if (y == gsl_histogram_max (gslh))
- {
- double lower, upper;
- gsl_histogram_get_range (gslh, gsl_histogram_bins (gslh)-1, &lower, &upper);
- gsl_histogram_accumulate (gslh, lower + (upper - lower)/2.0, c);
- }
- else
- gsl_histogram_accumulate (hist->gsl_hist, y, c);
+ gsl_histogram_accumulate (hist->gsl_hist, y, c);
}
static void
nbins = ceil((max-*adjusted_min)/binwidth);
*adjusted_max = nbins*binwidth + *adjusted_min;
+ /* adjusted_max should never be smaller than max but if it is equal
+ then the gsl_histogram will not add the cases which have max value */
+ if (*adjusted_max <= max)
+ {
+ *adjusted_max += binwidth;
+ nbins++;
+ }
+ assert (*adjusted_min <= min);
+
return nbins;
}
h->gsl_hist = gsl_histogram_alloc (bins);
- gsl_histogram_set_ranges_uniform (h->gsl_hist, adjusted_min, adjusted_max);
+ /* The bin ranges could be computed with gsl_histogram_set_ranges_uniform,
+ but the number of bins is adapted to the ticks of the axis such that for example
+ data ranging from 1.0 to 7.0 with 6 bins will have bin limits at
+ 2.0,3.0,4.0 and 5.0. Due to numerical accuracy the computed bin limits might
+ be 4.99999999 for a value which is expected to be 5.0. But the limits of
+ the histogram bins should be that what is expected from the displayed ticks.
+ Therefore the bin limits are computed from the rounded values which is similar
+ to the procedure at the chart_get_ticks_format. Actual bin limits should be
+ exactly what is displayed at the ticks.
+ But... I cannot reproduce the problem that I see with gsl_histogram_set_ranges_uniform
+ with the code below without rounding...
+ */
+ {
+ double *ranges = xmalloc (sizeof (double) * (bins + 1));
+ double interval = (adjusted_max - adjusted_min) / bins;
+ for (int i = 0; i < bins; i++)
+ ranges[i] = adjusted_min + interval * i;
+ ranges[bins] = adjusted_max;
+ gsl_histogram_set_ranges (h->gsl_hist, ranges, bins + 1);
+ free (ranges);
+ }
stat = &h->parent;
stat->accumulate = acc;