medfall

commit 7c885bf8a80528f8a1e2401220f5bc4f58b7aa3e
parent 8e63a85c27ce4688a3f063f74a3882db39d663a7
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Fri Jan  8 21:05:06 +0000

Add Stats

Diffstat:
stats.cc
 | 
42
++++++++++++++++++++++++++++++++++++++++++
stats.h
 | 
21
+++++++++++++++++++++
2 files changed, 63 insertions(+), 0 deletions(-)
diff --git a/stats.cc b/stats.cc
@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <math.h>
+
+#include "intrinsics.h"
+#include "stats.h"
+
+void stats_init( Stats * stats ) {
+	*stats = { };
+}
+
+double stats_mean( const Stats * stats ) {
+	return stats->sum / stats->num_samples;
+}
+
+double stats_stddev( const Stats * stats ) {
+	double variance = ( stats->sum_of_squares - ( stats->sum * stats->sum / stats->num_samples ) );
+	return sqrt( variance );
+}
+
+void stats_record( Stats * stats, double x ) {
+	stats->sum += x;
+	stats->sum_of_squares += x * x;
+
+	if( stats->num_samples == 0 ) {
+		stats->min = stats->max = x;
+	}
+	else {
+		if( x < stats->min ) stats->min = x;
+		if( x > stats->max ) stats->max = x;
+	}
+
+	stats->num_samples++;
+}
+
+void stats_print( const Stats * stats, const char * name ) {
+	printf( "[%s]\n\tn: %llu\n\tmean: %f\n\tstddev: %f\n\trange: %f to %f\n",
+		name, stats->num_samples,
+		stats_mean( stats ), stats_stddev( stats ),
+		stats->min, stats->max
+	);
+}
+
diff --git a/stats.h b/stats.h
@@ -0,0 +1,21 @@
+#ifndef _STATS_H_
+#define _STATS_H_
+
+#include "intrinsics.h"
+
+struct Stats {
+	double sum;
+	double sum_of_squares;
+	double min;
+	double max;
+	u64 num_samples;
+};
+
+
+void stats_init( Stats * stats );
+double stats_mean( const Stats * stats );
+double stats_stddev( const Stats * stats );
+void stats_record( Stats * stats, double x );
+void stats_print( const Stats * stats, const char * name );
+
+#endif // _STATS_H_