Bug 124158

Created attachment 15327 [details]
Proposed patch

Barth, could you confirm I'm on the right track here.

I don't have time right not to look at it carefully at the moment.  Maybe next 
week.  What definition are you using for normalization?

On Monday 27 March 2006 15:22, Andrew Walker wrote:
> Barth, could you confirm I'm on the right track here.

I apply the same normalization for each of the available apodizations as was already applied for the default case.

Barth, have you had a chance to look at this yet?

SVN commit 544476 by arwalker:

CCBUG:124158 Combine code for window generation so that it later only needs to be fixed in one place.

 M  +1 -0      kstcsd.cpp  
 M  +0 -1      kstcsd.h  
 M  +85 -81    kstpsd.cpp  
 M  +3 -1      kstpsd.h  
 M  +5 -84     kstpsdgenerator.cpp  
 M  +2 -1      kstpsdgenerator.h  

Enzo, could you give more details as to why you believe the normalization is incorrect for everything other than the default. Thanks.

SVN commit 544645 by arwalker:

BUG:124158 Normalize not just the default window, but all the others as well.

 M  +31 -0     kstpsd.cpp  


--- trunk/extragear/graphics/kst/src/libkstmath/kstpsd.cpp #544644:544645
@@ -236,28 +236,44 @@
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = (1.0 - fabs(x)/a);
+        sW += w[i] * w[i];
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // Blackman function 
     case 2:
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = 0.42 + 0.5*cos(M_PI*x/a) + 0.08*cos(2*M_PI*x/a);
+        sW += w[i] * w[i];
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // Connes function
     case 3: 
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = pow(1.0-(x*x)/(a*a), 2.0);
+        sW += w[i] * w[i];
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // cosine function
     case 4:
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = cos((M_PI*x)/(2.0*a));
+        sW += w[i] * w[i];
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // Gaussian function
     case 5:
@@ -265,27 +281,42 @@
         x = i-a;
         w[i] = exp((-1.0*x*x)/(2.0*gaussianSigma*gaussianSigma));
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // Hamming function
     case 6:
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = 0.53836 + 0.46164*cos(M_PI*x/a);
+        sW += w[i] * w[i];
       }  
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // Hann function
     case 7:
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = pow(cos((M_PI*x)/(2.0*a)), 2.0);
+        sW += w[i] * w[i];
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // Welch function
     case 8:
       for (i = 0; i < len; i++) {
         x = i-a;
         w[i] = 1.0 - (x*x)/(a*a);
+        sW += w[i] * w[i];
       }
+      for (i = 0; i < len; i++) {
+        w[i] /= sW;
+      }
       break;
     // uniform/rectangular function
     default:

'wrong' in that there are no 

sW = sqrt(sW / double(len));

calls, although this probably shouldn't have to be done here.

i'll commit a quick fix.

SVN commit 551186 by dhanson:

BUG:124158 sqrt(sW/len) for all apodizations.

 M  +9 -1      kstpsdgenerator.cpp  


--- trunk/extragear/graphics/kst/src/libkstmath/kstpsdgenerator.cpp #551185:551186
@@ -126,6 +126,7 @@
         w[i] = 1.0 - fabs(x) / a;
         sW += w[i] * w[i];
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -137,6 +138,7 @@
         w[i] = 0.42 + 0.5 * cos(M_PI * x / a) + 0.08 * cos(2 * M_PI * x/a);
         sW += w[i] * w[i];
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -148,6 +150,7 @@
         w[i] = pow(1.0 - (x * x) / (a * a), 2.0);
         sW += w[i] * w[i];
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -159,6 +162,7 @@
         w[i] = cos(M_PI * x / (2.0 * a));
         sW += w[i] * w[i];
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -169,6 +173,7 @@
         x = i - a;
         w[i] = exp(-1.0 * x * x/(2.0 * gaussianSigma * gaussianSigma));
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -179,7 +184,8 @@
         x = i - a;
         w[i] = 0.53836 + 0.46164 * cos(M_PI * x / a);
         sW += w[i] * w[i];
-      }  
+      }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -191,6 +197,7 @@
         w[i] = pow(cos(M_PI * x/(2.0 * a)), 2.0);
         sW += w[i] * w[i];
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }
@@ -202,6 +209,7 @@
         w[i] = 1.0 - x * x / (a * a);
         sW += w[i] * w[i];
       }
+      sW = sqrt(sW / double(len));
       for (int i = 0; i < len; ++i) {
         w[i] /= sW;
       }