initial commit

1 files changed, 35 insertions, 0 deletions

diff --git a/stats.h b/stats.h
new file mode 100644
index 0000000..8796161
--- /dev/null
+++ b/stats.h
@@ -0,0 +1,35 @@
+#pragma once
+#ifndef STATS_H
+#define STATS_H
+
+#include <math.h>
+
+struct stats_running {
+	unsigned n;
+	double   S;
+	double   m;
+};
+#define STATS_RUNNING_INIT {0, NAN, NAN}
+
+void stats_running_reset(struct stats_running *s);
+void stats_running_push(struct stats_running *s, double value);
+
+static inline
+unsigned stats_running_N(struct stats_running const *s)
+{
+	return s ? s->n : 0;
+}
+
+static inline
+double stats_running_mean(struct stats_running const *s)
+{
+	return s && (0 < s->n) ? s->m : NAN;
+}
+
+static inline
+double stats_running_variance(struct stats_running const *s)
+{
+	return s && (1 < s->n) ? s->S/s->n : NAN;
+}
+
+#endif/*STATS_H*/