Index: trunk/psModules/src/imcombine/pmStack.c
===================================================================
--- trunk/psModules/src/imcombine/pmStack.c	(revision 19487)
+++ trunk/psModules/src/imcombine/pmStack.c	(revision 19532)
@@ -8,6 +8,6 @@
  *  @author GLG, MHPCC
  *
- *  @version $Revision: 1.40 $ $Name: not supported by cvs2svn $
- *  @date $Date: 2008-09-11 20:52:16 $
+ *  @version $Revision: 1.41 $ $Name: not supported by cvs2svn $
+ *  @date $Date: 2008-09-12 04:12:42 $
  *  Copyright 2004-2007 Institute for Astronomy, University of Hawaii
  *
@@ -30,5 +30,5 @@
 #define PIXEL_LIST_BUFFER 100           // Number of entries to add to pixel list at a time
 #define PIXEL_MAP_BUFFER 2              // Number of entries to add to pixel map at a time
-//#define VARIANCE_FACTORS                // Use variance factors when calculating the variances?
+#define VARIANCE_FACTORS                // Use variance factors when calculating the variances?
 #define NUM_DIRECT_STDEV 5              // For less than this number of values, measure stdev directly
 
@@ -312,5 +312,5 @@
               // Use variance to check that the two are consistent
               float diff = pixelData->data.F32[0] - pixelData->data.F32[1];
-#if VARIANCE_FACTORS
+#ifdef VARIANCE_FACTORS
               float sigma2 = pixelVariances->data.F32[0] * varFactors->data.F32[pixelSources->data.U16[0]] +
                   pixelVariances->data.F32[1] * varFactors->data.F32[pixelSources->data.U16[1]];
@@ -346,5 +346,5 @@
                   float rej2 = PS_SQR(rej); // Rejection level squared
                   for (int i = 0; i < num; i++) {
-#if VARIANCE_FACTORS
+#ifdef VARIANCE_FACTORS
                       pixelVariances->data.F32[i] *= rej2 * varFactors->data.F32[pixelSources->data.U16[i]];
 #else
@@ -538,5 +538,5 @@
 
 /// Constructor
-pmStackData *pmStackDataAlloc(pmReadout *readout, float weight)
+pmStackData *pmStackDataAlloc(pmReadout *readout, float weight, float addVariance)
 {
     pmStackData *data = psAlloc(sizeof(pmStackData)); // Stack data, to return
@@ -547,4 +547,5 @@
     data->inspect = NULL;
     data->weight = weight;
+    data->addVariance = addVariance;
 
     return data;
@@ -602,4 +603,7 @@
         }
         varFactors->data.F32[i] = vf;
+        if (isfinite(data->addVariance)) {
+            varFactors->data.F32[i] *= data->addVariance;
+        }
         if (!haveRejects && !data->inspect) {
             data->inspect = psPixelsAllocEmpty(PIXEL_LIST_BUFFER);