From 96205ac2080f1ef71e4e06215b83bc001dbccc7f Mon Sep 17 00:00:00 2001
From: Philip Rosedale <philip@coffeeandpower.com>
Date: Mon, 4 Feb 2013 13:38:54 -0800
Subject: [PATCH] Added test for standard deviation calcs at startup.

---
 Source/Audio.cpp |  6 +++---
 Source/Util.cpp  | 10 +++++++---
 Source/main.cpp  | 31 +++++++++++++++++++++++++++++--
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/Source/Audio.cpp b/Source/Audio.cpp
index 37c2e9b69a..29b05dda40 100644
--- a/Source/Audio.cpp
+++ b/Source/Audio.cpp
@@ -84,7 +84,7 @@ int audioCallback (const void *inputBuffer,
 //    int16_t *inputRight = ((int16_t **) inputBuffer)[1];
     
     if (inputLeft != NULL) {
-        data->audioSocket->send((char *) EC2_WEST_AUDIO_SERVER, 55443, (void *)inputLeft, BUFFER_LENGTH_BYTES);
+        data->audioSocket->send((char *) WORKCLUB_AUDIO_SERVER, 55443, (void *)inputLeft, BUFFER_LENGTH_BYTES);
     }
     
     int16_t *outputLeft = ((int16_t **) outputBuffer)[0];
@@ -236,12 +236,12 @@ void *receiveAudioViaUDP(void *args) {
                 }
             }
             
-            //  Compute standard deviation for jitter
+            //  Compute and report standard deviation for jitter calculation
             if (firstSample) {
                 stdev.reset();
             } else {
                 stdev.addValue(diffclock(previousReceiveTime, currentReceiveTime));
-                if (stdev.getSamples() > 300) {
+                if (stdev.getSamples() > 500) {
                     printf("Avg: %4.2f, Stdev: %4.2f\n", stdev.getAverage(), stdev.getStDev());
                     stdev.reset();
                 }
diff --git a/Source/Util.cpp b/Source/Util.cpp
index 6eedd863b8..2fb5ad14eb 100644
--- a/Source/Util.cpp
+++ b/Source/Util.cpp
@@ -17,7 +17,11 @@
 #include "util.h"
 
 
-const int MAX_STDEV_SAMPLES = 1000;
+//
+//  Standard Deviation Object
+//
+
+const int MAX_STDEV_SAMPLES = 1000;                     //  Don't add more than this number of samples.  
 
 StDev::StDev() {
     data = new float[MAX_STDEV_SAMPLES];
@@ -49,8 +53,8 @@ float StDev::getStDev() {
     for (int i = 0; i < sampleCount; i++) {
         stdev += powf(data[i] - average, 2);
     }
-    if (sampleCount > 0)
-        return sqrt(stdev/(float)sampleCount);
+    if (sampleCount > 1)
+        return sqrt(stdev/(float)(sampleCount - 1.0));
     else
         return 0;
 }
diff --git a/Source/main.cpp b/Source/main.cpp
index 49e9bc6829..1dc89ffeee 100644
--- a/Source/main.cpp
+++ b/Source/main.cpp
@@ -903,8 +903,35 @@ int main(int argc, char** argv)
     int test_recv = network_receive(UDP_socket, &from_addr, incoming_packet, delay);
     printf("Received %i bytes\n", test_recv);
     
-       //  Load textures 
-    //Img.Load("/Users/philip/Downloads/galaxy1.tga");
+    //
+    printf("Testing math... standard deviation.\n");
+    StDev stdevtest;
+    stdevtest.reset();
+    stdevtest.addValue(1345);
+    stdevtest.addValue(1301);
+    stdevtest.addValue(1368);
+    stdevtest.addValue(1322);
+    stdevtest.addValue(1310);
+    stdevtest.addValue(1370);
+    stdevtest.addValue(1318);
+    stdevtest.addValue(1350);
+    stdevtest.addValue(1303);
+    stdevtest.addValue(1299);
+    
+    if (stdevtest.getSamples() == 10) 
+        printf("Samples=PASS ");
+    else
+        printf("Samples=FAIL ");
+        
+    if (floor(stdevtest.getAverage()*100.0) == 132859.0)
+        printf("Average=PASS ");
+    else
+        printf("Average=FAIL, avg reported = %5.3f ", floor(stdevtest.getAverage()*100.0));
+
+    if (floor(stdevtest.getStDev()*100.0) == 2746.0)
+        printf("Stdev=PASS \n");
+    else
+        printf("Stdev=FAIL \n");
 
     //
     //  Try to connect the serial port I/O