# HG changeset patch
# User Jamie Bullock <jamie@postlude.co.uk>
# Date 1168439803 0
# Node ID 04f536b139a8e72cfd4eba9521dc18a540807f14
# Parent  45c585bb79961c39d03d2317dfd3969e4a72105b
Made some changes to spectral_mean etc.

diff -r 45c585bb7996 -r 04f536b139a8 src/scalar.c
--- a/src/scalar.c	Wed Jan 10 13:16:55 2007 +0000
+++ b/src/scalar.c	Wed Jan 10 14:36:43 2007 +0000
@@ -130,14 +130,21 @@
 
 int xtract_spectral_variance(const float *data, const int N, const void *argv, float *result){
 
-    int M, m;
+    int m;
+    float A = 0.f;
+    const float *freqs, *amps;
 
-    m = M = N >> 1;
+    m = N >> 1;
 
-    while(m--)
-	*result += pow((data[m] * data[M +m])  - *(float *)argv, 2);
+    amps = data;
+    freqs = data + m;
 
-    *result = *result / (M - 1);
+    while(m--){
+	A += amps[m];
+	*result += pow((freqs[m]  - *(float *)argv) * amps[m], 2);
+    }
+
+    *result = *result / (A - 1);
 
     return SUCCESS;
 }
@@ -151,50 +158,67 @@
 
 int xtract_spectral_average_deviation(const float *data, const int N, const void *argv, float *result){
 
-    int M, m;
+    int m;
+    float A = 0.f;
+    const float *freqs, *amps;
 
-    m = M = N >> 1;
+    m = N >> 1;
 
-    while(m--)
-	*result += fabs((data[m] * data[M + m]) - *(float *)argv);
+    amps = data;
+    freqs = data + m;
 
-    *result /= M;
+    while(m--){
+	A += amps[m];
+	*result += fabs((amps[m] * freqs[m]) - *(float *)argv);
+    }
+
+    *result /= A;
 
     return SUCCESS;
 }
 
 int xtract_spectral_skewness(const float *data, const int N, const void *argv,  float *result){
 
-    int M, m;
-    float temp;
+    int m;
+    float temp, A = 0.f;
+    const float *freqs, *amps;
 
-    m = M = N >> 1;
+    m = N >> 1;
+
+    amps = data;
+    freqs = data + m;
 
     while(m--){
-	temp = ((data[m] * data[M + m]) - 
+	A += amps[m];
+	temp = ((amps[m] * freqs[m]) - 
 		((float *)argv)[0]) / ((float *)argv)[1];
 	*result += pow(temp, 3);
     }
 
-    *result /= M;
+    *result /= A;
 
     return SUCCESS;
 }
 
 int xtract_spectral_kurtosis(const float *data, const int N, const void *argv,  float *result){
 
-    int M, m;
-    float temp;
+    int m;
+    float temp, A = 0.f;
+    const float *freqs, *amps;
 
-    m = M = N >> 1;
+    m = N >> 1;
+
+    amps = data;
+    freqs = data + m;
 
     while(m--){
-	temp = ((data[m] * data[M + m]) - 
+	A += amps[m];
+	temp = ((amps[m] * freqs[m]) - 
 		((float *)argv)[0]) / ((float *)argv)[1];
 	*result += pow(temp, 4);
     }
 
-    *result /= M;
+    *result /= A;
     *result -= 3.0f;
 
     return SUCCESS;