Update.

[pspp-builds.git] / src / moments.h

diff --git a/src/moments.h b/src/moments.h
index e48bfd5ec6f7930089cef29042a3f00b79ccb1cb..791e9c546916535e6b6d2b77fc029459cf231161 100644 (file)
--- a/src/moments.h
+++ b/src/moments.h
@@ -36,6 +36,7 @@ enum moment
 
 struct moments;
 
+/* Two-pass moments. */
 struct moments *moments_create (enum moment max_moment);
 void moments_clear (struct moments *);
 void moments_pass_one (struct moments *, double value, double weight);
@@ -46,6 +47,7 @@ void moments_calculate (const struct moments *,
                         double *skewness, double *kurtosis);
 void moments_destroy (struct moments *);
 
+/* Convenience functions for two-pass moments. */
 void moments_of_doubles (const double *array, size_t cnt,
                          double *weight,
                          double *mean, double *variance,
@@ -55,6 +57,18 @@ void moments_of_values (const union value *array, size_t cnt,
                         double *mean, double *variance,
                         double *skewness, double *kurtosis);
 
+/* One-pass moments.  Use only if two passes are impractical. */
+struct moments1 *moments1_create (enum moment max_moment);
+void moments1_clear (struct moments1 *);
+void moments1_add (struct moments1 *, double value, double weight);
+void moments1_calculate (const struct moments1 *,
+                         double *weight,
+                         double *mean, double *variance,
+                         double *skewness, double *kurtosis);
+void moments1_destroy (struct moments1 *);
+
+/* Standard errors. */
+double calc_semean (double stddev, double weight);
 double calc_seskew (double weight);
 double calc_sekurt (double weight);