[Kst] kdeextragear-2/kst/plugins/crossspectrum

[Barth Netterfield]

CVS commit by netterfield: 

cross spectrum plugin was incorrect mathematically... this fixes it.


  M +9 -3      crossspectrum.cpp   1.2
  M +4 -1      crossspectrum.xml   1.2


--- kdeextragear-2/kst/plugins/crossspectrum/crossspectrum.cpp  #1.1:1.2
@@ -63,6 +63,8 @@ int crossspectrum(const double *const in
     outArrays[0] = (double *) realloc(outArrays[0], xps_len*sizeof(double));
     outArrays[1] = (double *) realloc(outArrays[1], xps_len*sizeof(double));
+    outArrays[2] = (double *) realloc(outArrays[2], xps_len*sizeof(double));
     outArrayLens[0] = xps_len;
     outArrayLens[1] = xps_len;
+    outArrayLens[2] = xps_len;
   }
 
@@ -70,6 +72,7 @@ int crossspectrum(const double *const in
   df = SR/( 2.0*double( xps_len-1 ) );
   for ( i=0; i<xps_len; i++ ) {
-    outArrays[1][i] = double( i ) * df;
+    outArrays[2][i] = double( i ) * df;
     outArrays[0][i] = 0.0;
+    outArrays[1][i] = 0.0;
   }
 
@@ -124,7 +127,9 @@ int crossspectrum(const double *const in
     outArrays[0][xps_len-1] += ( a[1]*b[1] );
     for (i_samp=1; i_samp<xps_len-1; i_samp++) {
-      outArrays[0][i_samp]+= ( a[i_samp*2] * b[i_samp*2] +
+      outArrays[0][i_samp]+= ( a[i_samp*2] * b[i_samp*2] -
                                    a[i_samp*2+1] * b[i_samp*2+1] );
-    }
+      outArrays[1][i_samp]+= ( -a[i_samp*2] * b[i_samp*2+1] +
+                                   a[i_samp*2+1] * b[i_samp*2] );
+    }// (a+ci)(b+di)* = ab+cd +i(-ad + cb)
   }
 
@@ -133,4 +138,5 @@ int crossspectrum(const double *const in
   for ( i=0; i<xps_len; i++ ) {
     outArrays[0][i]*=norm_factor;
+    outArrays[1][i]*=norm_factor;
   }
 

--- kdeextragear-2/kst/plugins/crossspectrum/crossspectrum.xml  #1.1:1.2
@@ -26,5 +26,8 @@
 
 <output>
-<table type="float" name="Cross Spectrum" descr="The cross power spectrum." />
+<table type="float" name="Cross Spectrum: Real" descr="The cross power spectrum." />
+</output>
+<output>
+<table type="float" name="Cross Spectrum: Imaginary" descr="The cross power spectrum." />
 </output>
 <output>