Index: trunk/psphot/configure.ac
===================================================================
--- trunk/psphot/configure.ac	(revision 33994)
+++ trunk/psphot/configure.ac	(revision 34086)
@@ -9,5 +9,5 @@
 AM_MAINTAINER_MODE
 
-IPP_STDCFLAGS
+IPP_STDLDFLAGS
 
 AC_LANG(C)
@@ -199,6 +199,6 @@
 dnl Set CFLAGS for build
 IPP_STDOPTS
-
-CFLAGS="${CFLAGS=} -Wall -Werror"
+IPP_STDCFLAGS
+
 echo "PSPHOT_CFLAGS: $PSPHOT_CFLAGS"
 echo "PSPHOT_LIBS: $PSPHOT_LIBS"
@@ -206,4 +206,6 @@
 IPP_VERSION
 
+dnl note: the PSPHOT_ entries below do not include PSLIB_ and PSMODULE_ entires
+dnl those are passed down to lower Makefiles by the PKG_CHECK_MODULES call above
 AC_SUBST([PSPHOT_CFLAGS])
 AC_SUBST([PSPHOT_LIBS])
Index: trunk/psphot/src/Makefile.am
===================================================================
--- trunk/psphot/src/Makefile.am	(revision 33994)
+++ trunk/psphot/src/Makefile.am	(revision 34086)
@@ -183,5 +183,4 @@
 	psphotSourcePlots.c	       \
 	psphotRadialPlot.c	       \
-	psphotKronMasked.c             \
 	psphotKronIterate.c            \
 	psphotRadialProfileWings.c     \
@@ -209,8 +208,9 @@
 	psphotSetNFrames.c
 
-# re-instate these
+# not currently used
 #	psphotIsophotal.c	       \
 #	psphotAnnuli.c		       \
 #	psphotKron.c		       \
+#	psphotKronMasked.c             \
 #
 
Index: trunk/psphot/src/psphot.h
===================================================================
--- trunk/psphot/src/psphot.h	(revision 33994)
+++ trunk/psphot/src/psphot.h	(revision 34086)
@@ -61,4 +61,7 @@
 bool            psphotSetMaskAndVarianceReadout (pmConfig *config, const pmFPAview *view, const char *filerule, int index, psMetadata *recipe);
 
+bool            psphotUpdateVariance (pmConfig *config, const pmFPAview *view, const char *filerule);
+bool            psphotUpdateVarianceReadout (pmConfig *config, const pmFPAview *view, const char *filerule, int index, psMetadata *recipe);
+
 bool            psphotModelBackground (pmConfig *config, const pmFPAview *view, const char *filerule);
 bool            psphotModelBackgroundReadoutFileIndex (pmConfig *config, const pmFPAview *view, const char *filerule, int index);
@@ -99,10 +102,5 @@
 
 bool            psphotFitSourcesLinear (pmConfig *config, const pmFPAview *view, const char *filerule, bool final);
-
-# if (HAVE_MODEL_VAR)
 bool            psphotFitSourcesLinearReadout (psMetadata *recipe, pmReadout *readout, psArray *sources, pmPSF *psf, bool final, pmSourceFitVarMode fitVarMode);
-# else
-bool            psphotFitSourcesLinearReadout (psMetadata *recipe, pmReadout *readout, psArray *sources, pmPSF *psf, bool final);
-# endif
 
 bool            psphotSourceSize (pmConfig *config, const pmFPAview *view, const char *filerule, bool getPSFsize);
@@ -489,3 +487,16 @@
 bool psphotSetNFramesReadout (pmConfig *config, const pmFPAview *view, const char *filerule, int index);
 
+bool psphotGenerateModelVariance (pmConfig *config, const pmFPAview *view, pmFPAfile *file, int index, psMetadata *recipe, pmReadout *readout, psArray *sources);
+pmSourceFitVarMode psphotGetFitVarMode (psMetadata *recipe);
+bool psphotFreeModelVariance (pmReadout *readout, psArray *sources);
+
+bool psphotModelBackgroundReadout(psImage *model,  // Model image
+				  psImage *modelStdev, // Model stdev image
+				  psMetadata *analysis, // Analysis metadata for outputs
+				  pmReadout *readout, // Readout for which to generate a background model
+				  psImageBinning *binning, // Binning parameters
+				  const pmConfig *config,// Configuration
+				  bool useVarianceImage
+    );
+
 #endif
Index: trunk/psphot/src/psphotCleanup.c
===================================================================
--- trunk/psphot/src/psphotCleanup.c	(revision 33994)
+++ trunk/psphot/src/psphotCleanup.c	(revision 34086)
@@ -29,5 +29,13 @@
 psExit psphotGetExitStatus (void) {
 
-    psErrorCode err = psErrorCodeLast ();
+    // gcc -Wswitch complains here if err is declared as type psErrorCode
+    // the collection of ps*ErrorCode values are enums defined separately for 
+    // each module (psphot, pswarp, etc).  the lowest type, psErrorCode is only the base set and does
+    // not include the possible psphot values
+
+    // for now, to get around this, we just use an int for the switch
+
+    // psErrorCode err = psErrorCodeLast ();
+    int err = psErrorCodeLast ();
     switch (err) {
       case PS_ERR_NONE:
Index: trunk/psphot/src/psphotEfficiency.c
===================================================================
--- trunk/psphot/src/psphotEfficiency.c	(revision 33994)
+++ trunk/psphot/src/psphotEfficiency.c	(revision 34086)
@@ -420,9 +420,5 @@
 
     // psphotFitSourcesLinearReadout subtracts the model fits
-# if (HAVE_MODEL_VAR)
     if (!psphotFitSourcesLinearReadout(recipe, readout, fakeSourcesAll, psf, true, PM_SOURCE_PHOTFIT_CONST)) {
-# else
-    if (!psphotFitSourcesLinearReadout(recipe, readout, fakeSourcesAll, psf, true)) {
-# endif
         psError(PS_ERR_UNKNOWN, false, "Unable to perform linear fit on fake sources.");
         psFree(fakeSources);
Index: trunk/psphot/src/psphotFitSourcesLinear.c
===================================================================
--- trunk/psphot/src/psphotFitSourcesLinear.c	(revision 33994)
+++ trunk/psphot/src/psphotFitSourcesLinear.c	(revision 34086)
@@ -12,10 +12,4 @@
 static bool SetBorderMatrixElements (psSparseBorder *border, pmReadout *readout, psArray *sources, bool constant_weights, int SKY_FIT_ORDER, psImageMaskType markVal);
 
-# if (HAVE_MODEL_VAR)
-bool psphotGenerateModelVariance (pmConfig *config, const pmFPAview *view, pmFPAfile *file, int index, psMetadata *recipe, pmReadout *readout, psArray *sources);
-pmSourceFitVarMode psphotGetFitVarMode (psMetadata *recipe);
-bool psphotFreeModelVariance (pmReadout *readout, psArray *sources);
-# endif
-
 // for now, let's store the detections on the readout->analysis for each readout
 bool psphotFitSourcesLinear (pmConfig *config, const pmFPAview *view, const char *filerule, bool final)
@@ -30,5 +24,4 @@
     assert (recipe);
 
-# if (HAVE_MODEL_VAR)
     pmSourceFitVarMode fitVarMode = psphotGetFitVarMode (recipe);
     if (!fitVarMode) {
@@ -40,5 +33,4 @@
     // do a single pass.
     pmSourceFitVarMode fitVarModePass1 = (fitVarMode == PM_SOURCE_PHOTFIT_MODEL_VAR) ? PM_SOURCE_PHOTFIT_CONST : fitVarMode;
-# endif
 
     int num = psphotFileruleCount(config, filerule);
@@ -68,15 +60,9 @@
         psAssert (psf, "missing psf?");
 
-# if (HAVE_MODEL_VAR)
-        if (!psphotFitSourcesLinearReadout (recipe, readout, sources, psf, final, fitVarModePass1))
-# else
-        if (!psphotFitSourcesLinearReadout (recipe, readout, sources, psf, final))
-# endif
-	{
+        if (!psphotFitSourcesLinearReadout (recipe, readout, sources, psf, final, fitVarModePass1)) {
             psError (PSPHOT_ERR_CONFIG, false, "failed to fit sources (linear) for %s entry %d", filerule, i);
             return false;
         }
 
-# if (HAVE_MODEL_VAR)
 	// the MODEL_VAR weighting scheme requires knowledge of the model fluxes to generate the variance
 	// after we have determined the initial set of fits, then we can generate the variance image and 
@@ -104,5 +90,4 @@
 	    }
 	}
-# endif
 
 	psphotVisualShowResidualImage (readout, (num > 0)); 
@@ -113,5 +98,4 @@
 }
 
-# if (HAVE_MODEL_VAR)
 // look up the fit variance mode from the recipe; older recipes do not have the value
 // 'LINEAR_FIT_VARIANCE_MODE'; in those cases, look for 'CONSTANT_PHOTOMETRIC_WEIGHTS' as a boolean and
@@ -136,4 +120,7 @@
 	return PM_SOURCE_PHOTFIT_IMAGE_VAR;
     }
+    if (!strcasecmp(fitVarModeString, "SKY")   || !strcasecmp(fitVarModeString, "MODEL_SKY")) {
+	return PM_SOURCE_PHOTFIT_MODEL_SKY;
+    }
     if (!strcasecmp(fitVarModeString, "MODEL") || !strcasecmp(fitVarModeString, "MODEL_VAR")) {
 	return PM_SOURCE_PHOTFIT_MODEL_VAR;
@@ -142,12 +129,6 @@
     return PM_SOURCE_PHOTFIT_NONE;
 }
-# endif
-
-# if (HAVE_MODEL_VAR)
-bool psphotFitSourcesLinearReadout (psMetadata *recipe, pmReadout *readout, psArray *sources, pmPSF *psf, bool final, pmSourceFitVarMode fitVarMode)
-# else
-bool psphotFitSourcesLinearReadout (psMetadata *recipe, pmReadout *readout, psArray *sources, pmPSF *psf, bool final)
-# endif
-{
+
+bool psphotFitSourcesLinearReadout (psMetadata *recipe, pmReadout *readout, psArray *sources, pmPSF *psf, bool final, pmSourceFitVarMode fitVarMode) {
     bool status;
     float x;
@@ -185,11 +166,4 @@
     if (psRegionIsNaN (AnalysisRegion)) psAbort("analysis region mis-defined");
 
-# if (!HAVE_MODEL_VAR)
-    bool CONSTANT_PHOTOMETRIC_WEIGHTS =
-        psMetadataLookupBool(&status, recipe, "CONSTANT_PHOTOMETRIC_WEIGHTS");
-    if (!status) {
-        psAbort("You must provide a value for the BOOL recipe CONSTANT_PHOTOMETRIC_WEIGHTS");
-    }
-# endif
     int SKY_FIT_ORDER = psMetadataLookupS32(&status, recipe, "SKY_FIT_ORDER");
     if (!status) {
@@ -299,5 +273,5 @@
 	    source->mode |= PM_SOURCE_MODE_PSFMODEL;
 	}	    
-	
+
         psArrayAdd (fitSources, 100, source);
     }
@@ -319,5 +293,4 @@
     psSparseBorder *border = psSparseBorderAlloc (sparse, nBorder);
 
-# if (HAVE_MODEL_VAR)
     // if fitVarMode is MODEL_VAR, then we need to generate the model image variance
     // XXX we have two possibilities here: 
@@ -327,5 +300,4 @@
 
     // 2) do a single pass, and use the model guess to define the model variance (but do I trust the Model Guess?)
-# endif
 
     // fill out the sparse matrix elements and border elements (B)
@@ -336,58 +308,29 @@
 
         // diagonal elements of the sparse matrix (auto-cross-product)
-# if (HAVE_MODEL_VAR)
-        f = pmSourceModelDotModel (SRCi, SRCi, fitVarMode, covarFactor, maskVal);
-# else
-        f = pmSourceModelDotModel (SRCi, SRCi, CONSTANT_PHOTOMETRIC_WEIGHTS, covarFactor, maskVal);
-# endif
-        psSparseMatrixElement (sparse, i, i, f);
-
-# if (HAVE_MODEL_VAR)
-        // if we have used CONSTANT errors, then we need to calculate the value of the parameter error
+        float MM = pmSourceModelDotModel (SRCi, SRCi, fitVarMode, covarFactor, maskVal);
+        psSparseMatrixElement (sparse, i, i, MM);
+
+        // if we have used CONSTANT errors, then we need to re-calculate the value of the parameter error
         if (fitVarMode != PM_SOURCE_PHOTFIT_IMAGE_VAR) {
             float var = pmSourceModelDotModel (SRCi, SRCi, PM_SOURCE_PHOTFIT_IMAGE_VAR, covarFactor, maskVal);
             errors->data.F32[i] = 1.0 / sqrt(var);
         } else {
-            errors->data.F32[i] = 1.0 / sqrt(f);
-        }
-# else
-        // the formal error depends on the weighting scheme
-        if (CONSTANT_PHOTOMETRIC_WEIGHTS) {
-            float var = pmSourceModelDotModel (SRCi, SRCi, false, covarFactor, maskVal);
-            errors->data.F32[i] = 1.0 / sqrt(var);
-        } else {
-            errors->data.F32[i] = 1.0 / sqrt(f);
-        }
-# endif
+            errors->data.F32[i] = 1.0 / sqrt(MM);
+        }
 
         // find the image x model value
-# if (HAVE_MODEL_VAR)
-        f = pmSourceDataDotModel (SRCi, SRCi, fitVarMode, covarFactor, maskVal);
-# else
-        f = pmSourceDataDotModel (SRCi, SRCi, CONSTANT_PHOTOMETRIC_WEIGHTS, covarFactor, maskVal);
-# endif
-        psSparseVectorElement (sparse, i, f);
+        float FM = pmSourceDataDotModel (SRCi, SRCi, fitVarMode, covarFactor, maskVal);
+        psSparseVectorElement (sparse, i, FM);
 
         // add the per-source variances (border region)
         switch (SKY_FIT_ORDER) {
           case 1:
-# if (HAVE_MODEL_VAR)
             f = pmSourceModelWeight (SRCi, 1, fitVarMode, covarFactor, maskVal);
             psSparseBorderElementB (border, i, 1, f);
             f = pmSourceModelWeight (SRCi, 2, fitVarMode, covarFactor, maskVal);
             psSparseBorderElementB (border, i, 2, f);
-# else
-            f = pmSourceModelWeight (SRCi, 1, CONSTANT_PHOTOMETRIC_WEIGHTS, covarFactor, maskVal);
-            psSparseBorderElementB (border, i, 1, f);
-            f = pmSourceModelWeight (SRCi, 2, CONSTANT_PHOTOMETRIC_WEIGHTS, covarFactor, maskVal);
-            psSparseBorderElementB (border, i, 2, f);
-# endif
 
           case 0:
-# if (HAVE_MODEL_VAR)
             f = pmSourceModelWeight (SRCi, 0, fitVarMode, covarFactor, maskVal);
-# else
-            f = pmSourceModelWeight (SRCi, 0, CONSTANT_PHOTOMETRIC_WEIGHTS, covarFactor, maskVal);
-# endif
             psSparseBorderElementB (border, i, 0, f);
             break;
@@ -409,9 +352,5 @@
 
             // got an overlap; calculate cross-product and add to output array
-# if (HAVE_MODEL_VAR)
             f = pmSourceModelDotModel (SRCi, SRCj, fitVarMode, covarFactor, maskVal);
-# else
-            f = pmSourceModelDotModel (SRCi, SRCj, CONSTANT_PHOTOMETRIC_WEIGHTS, covarFactor, maskVal);
-# endif
             psSparseMatrixElement (sparse, j, i, f);
         }
@@ -451,9 +390,5 @@
 
     // set the sky, sky_x, sky_y components of border matrix
-# if (HAVE_MODEL_VAR)
     SetBorderMatrixElements (border, readout, fitSources, (fitVarMode == PM_SOURCE_PHOTFIT_CONST), SKY_FIT_ORDER, markVal);
-# else
-    SetBorderMatrixElements (border, readout, fitSources, CONSTANT_PHOTOMETRIC_WEIGHTS, SKY_FIT_ORDER, markVal);
-# endif
 
     psSparseConstraint constraint;
@@ -500,4 +435,9 @@
     psLogMsg ("psphot.ensemble", PS_LOG_MINUTIA, "sub models: %f sec (%d elements)\n", psTimerMark ("psphot.linear"), sparse->Nelem);
 
+    // mean stats on fit windows
+    float sumRadius = 0.0;
+    float sumPixels = 0.0;
+    float sumSource = 0.0;
+
     // measure chisq for each source
     // for (int i = 0; final && (i < fitSources->n); i++) {
@@ -505,4 +445,10 @@
         pmSource *source = fitSources->data[i];
         pmModel *model = pmSourceGetModel (NULL, source);
+
+	// accumulate fit windows statistics
+        sumRadius += model->fitRadius;
+	sumPixels += M_PI*PS_SQR(model->fitRadius);
+	sumSource += 1.0;
+
         if (!(source->mode & PM_SOURCE_MODE_NONLINEAR_FIT)) {
 	    model->nPar = 1; // LINEAR-only sources have 1 parameter; NONLINEAR sources have their original value
@@ -511,4 +457,7 @@
     }
     psLogMsg ("psphot.ensemble", PS_LOG_MINUTIA, "get chisqs: %f sec (%d elements)\n", psTimerMark ("psphot.linear"), sparse->Nelem);
+
+    float meanRadius = sumRadius / sumSource;
+    float meanPixels = sumPixels / sumSource;
 
     // psFree (index);
@@ -520,5 +469,5 @@
     psFree (border);
 
-    psLogMsg ("psphot.ensemble", PS_LOG_WARN, "measure ensemble of PSFs: %f sec\n", psTimerMark ("psphot.linear"));
+    psLogMsg ("psphot.ensemble", PS_LOG_WARN, "measure ensemble of PSFs (mean radius = %f pixels, mean area = %f pixels: %f sec\n", meanRadius, meanPixels, psTimerMark ("psphot.linear"));
 
     psphotVisualPlotChisq (sources);
@@ -531,7 +480,4 @@
     return true;
 }
-
-// XXX do we need this?
-// XXX disallow the simultaneous sky fit and remove this code...
 
 // Calculate the weight terms for the sky fit component of the matrix.  This function operates
@@ -614,5 +560,4 @@
 }
 
-# if (HAVE_MODEL_VAR)
 bool psphotModelBackgroundReadout(psImage *model,  // Model image
 				  psImage *modelStdev, // Model stdev image
@@ -624,5 +569,5 @@
     );
 
-bool psphotGenerateModelVariance (pmConfig *config, const pmFPAview *view, pmFPAfile *file, int index, psMetadata *recipe, pmReadout *readout, psArray *sources) {
+ bool psphotGenerateModelVariance (pmConfig *config, const pmFPAview *view, pmFPAfile *file, int index, psMetadata *recipe, pmReadout *readout, psArray *sources) {
 
     bool status = false;
@@ -650,4 +595,5 @@
     psImage *varModelStdev = psImageAlloc(backBinning->nXruff, backBinning->nYruff, PS_TYPE_F32); // Background model
 
+    // generate an image of the mean variance image in DN
     if (!psphotModelBackgroundReadout(varModel, varModelStdev, NULL, readout, backBinning, config, true)) {
 	psError(PS_ERR_UNKNOWN, false, "Unable to generate background model");
@@ -664,10 +610,17 @@
 	return false;
     }
-
     psFree (varModel);
     psFree (varModelStdev);
 
-    // XXX for a test:
-    psphotSaveImage (NULL, modelVar, "model.bck.fits");
+    float gain = 1.0;  // accept 1.0 as a default since it is not critical to the analysis
+    pmCell *cell = readout->parent; // The parent cell
+    if (cell) {
+      gain = psMetadataLookupF32(&status, cell->concepts, "CELL.GAIN"); // Cell gain
+      if (!status) {
+	gain = 1.0;	      // set note above
+      }
+    }
+    if (gain > 2.0) { /* warn? */ }
+    // XXX we are not actually using the gain, but need to test it to avoid gcc pedantic warnings
 
     // insert all of the source models
@@ -690,10 +643,9 @@
 
 	// add the source model to the model variance image
+	// XXX note that this should be added with gain applied
+	// var_DN = flux_DN / gain [e/DN]
+	// to do this requires an API upgrade...
 	pmSourceAdd (source, PM_MODEL_OP_MODELVAR, maskVal);
     }
-
-    // XXX for a test:
-    psphotSaveImage (NULL, modelVar, "model.var.fits");
-    psphotSaveImage (NULL, readout->variance, "image.var.fits");
 
     // we save the model variance for future reference
@@ -724,3 +676,2 @@
     return true;
 }
-# endif
Index: trunk/psphot/src/psphotImageLoop.c
===================================================================
--- trunk/psphot/src/psphotImageLoop.c	(revision 33994)
+++ trunk/psphot/src/psphotImageLoop.c	(revision 34086)
@@ -164,4 +164,5 @@
     pmFPAfileActivate (config->files, true, "PSPHOT.EXPNUM");
     while ((chip = pmFPAviewNextChip (view, input->fpa, 1)) != NULL) {
+        if (! chip->process || ! chip->file_exists) { continue; }
         if (!pmFPAfileIOChecks (config, view, PM_FPA_BEFORE)) ESCAPE ("failed attempting to load EXPNUM input for Chip in psphot.");
         while ((cell = pmFPAviewNextCell (view, input->fpa, 1)) != NULL) {
Index: trunk/psphot/src/psphotMakeResiduals.c
===================================================================
--- trunk/psphot/src/psphotMakeResiduals.c	(revision 33994)
+++ trunk/psphot/src/psphotMakeResiduals.c	(revision 34086)
@@ -177,8 +177,6 @@
 
                 mflux = 0;
-                bool offImage = false;
                 if (psImageInterpolate (&flux, &dflux, &mflux, ix, iy, interp) == PS_INTERPOLATE_STATUS_OFF) {
                     // This pixel is off the image
-                    offImage = true;
                     fmasks->data.PS_TYPE_VECTOR_MASK_DATA[i] = badMask;
                 } else {
Index: trunk/psphot/src/psphotMaskReadout.c
===================================================================
--- trunk/psphot/src/psphotMaskReadout.c	(revision 33994)
+++ trunk/psphot/src/psphotMaskReadout.c	(revision 34086)
@@ -94,5 +94,5 @@
 
     // test output of files at this stage
-    if (psTraceGetLevel("psphot") >= 5) {
+    if (psTraceGetLevel("psphot.imsave") >= 5) {
         psphotSaveImage (NULL, readout->image,  "image.fits");
         psphotSaveImage (NULL, readout->mask,   "mask.fits");
@@ -105,2 +105,99 @@
     return true;
 }
+
+// XXX this function and support below was created to test the theory that the faint-end
+// bias results from the Poisson variation of the background pixels.  This is NOT the
+// case.  Using the code below maintains the faint-end bias.
+bool psphotUpdateVariance (pmConfig *config, const pmFPAview *view, const char *filerule) {
+
+    bool status = false;
+
+    // select the appropriate recipe information
+    psMetadata *recipe  = psMetadataLookupPtr (&status, config->recipes, PSPHOT_RECIPE);
+    psAssert (recipe, "missing recipe?");
+
+    int num = psphotFileruleCount(config, filerule);
+
+    // loop over the available readouts
+    for (int i = 0; i < num; i++) {
+
+	// Generate the mask and weight images, including the user-defined analysis region of interest
+	if (!psphotUpdateVarianceReadout (config, view, filerule, i, recipe)) {
+	    psError (PSPHOT_ERR_CONFIG, false, "failed to generate mask for %s entry %d", filerule, i);
+	    return false;
+	}
+    }
+    return true;
+}
+
+// determine the mean variance image (equivalent to the background model, but for the variance image)
+// set the variance image to the MAX(input, mean)
+bool psphotUpdateVarianceReadout (pmConfig *config, const pmFPAview *view, const char *filerule, int index, psMetadata *recipe) {
+
+    pmFPAfile *file = pmFPAfileSelectSingle(config->files, filerule, index); // File of interest
+    psAssert (file, "missing file?");
+
+    // find the currently selected readout
+    pmReadout  *readout = pmFPAviewThisReadout (view, file->fpa);
+    psAssert (readout, "missing readout?");
+
+    pmSourceFitVarMode varMode = psphotGetFitVarMode (recipe);
+    if (varMode == PM_SOURCE_PHOTFIT_NONE) {
+      psError (PSPHOT_ERR_CONFIG, false, "need valid LINEAR_FIT_VARIANCE_MODE");
+      return false;
+    }
+
+    // make this an option via the recipe
+    if (varMode != PM_SOURCE_PHOTFIT_MODEL_SKY) return true;
+
+    // create a model variance image (full-scale image to take result of psImageUnbin below)
+    psImage *modelVar = psImageCopy (NULL, readout->variance, PS_TYPE_F32);
+
+    // find the binning information
+    psImageBinning *backBinning = psphotBackgroundBinning (modelVar, config);
+    assert (backBinning);
+    
+    psImage *varModel = psImageAlloc(backBinning->nXruff, backBinning->nYruff, PS_TYPE_F32); // Background model
+    psImage *varModelStdev = psImageAlloc(backBinning->nXruff, backBinning->nYruff, PS_TYPE_F32); // Background model
+
+    if (!psphotModelBackgroundReadout(varModel, varModelStdev, NULL, readout, backBinning, config, true)) {
+	psError(PS_ERR_UNKNOWN, false, "Unable to generate background model");
+	psFree (varModel);
+	psFree (varModelStdev);
+	return false;
+    }
+
+    // linear interpolation to full-scale
+    if (!psImageUnbin (modelVar, varModel, backBinning)) {
+	psError (PSPHOT_ERR_PROG, true, "inconsistent sizes for unbinning");
+	psFree (varModel);
+	psFree (varModelStdev);
+	return false;
+    }
+
+    // XXX save these?
+    psFree (varModel);
+    psFree (varModelStdev);
+
+    psImage *im = readout->image;
+    psImage *wt = readout->variance;
+    for (int j = 0; j < im->numRows; j++) {
+      for (int i = 0; i < im->numCols; i++) {
+	if (!isfinite(im->data.F32[j][i])) continue;
+	if (!isfinite(wt->data.F32[j][i])) continue;
+	// XXX for a test, make variance constant wt->data.F32[j][i] = PS_MAX(wt->data.F32[j][i], modelVar->data.F32[j][i]);
+	wt->data.F32[j][i] = modelVar->data.F32[j][i];
+      }
+    }
+
+    // test output of files at this stage
+    if (psTraceGetLevel("psphot.imsave") >= 5) {
+        psphotSaveImage (NULL, readout->image,  "image.varsky.fits");
+        psphotSaveImage (NULL, readout->mask,   "mask.varsky.fits");
+        psphotSaveImage (NULL, readout->variance, "variance.varsky.fits");
+    }
+
+    psFree (modelVar);
+
+    return true;
+}
Index: trunk/psphot/src/psphotPetrosianStats.c
===================================================================
--- trunk/psphot/src/psphotPetrosianStats.c	(revision 33994)
+++ trunk/psphot/src/psphotPetrosianStats.c	(revision 34086)
@@ -46,5 +46,5 @@
 
     bool anyPetro = false;
-    bool manyPetro = false;
+    // bool manyPetro = false;  XXX not used
     bool above = true;
     float Asum = 0.0;
@@ -122,5 +122,5 @@
 	    }
 	    above = false;
-	    if (anyPetro) manyPetro = true;
+	    // if (anyPetro) manyPetro = true;
 	    anyPetro = true;
 	}
@@ -212,5 +212,5 @@
     source->extpars->petrosianR50    = R50;
     source->extpars->petrosianR90    = R90;
-    source->extpars->petrosianFill      = petApix / petArea;
+    source->extpars->petrosianFill   = petApix / petArea;
     
     // XXX add the errors
Index: trunk/psphot/src/psphotReadout.c
===================================================================
--- trunk/psphot/src/psphotReadout.c	(revision 33994)
+++ trunk/psphot/src/psphotReadout.c	(revision 34086)
@@ -9,4 +9,49 @@
 }
 
+# if (0)
+// TEST CODE, can be removed
+bool psphotDumpFlux (pmConfig *config, const pmFPAview *view, const char *filerule) {
+
+    bool status = false;
+
+    // find the currently selected readout
+    pmFPAfile *file = pmFPAfileSelectSingle(config->files, filerule, 0); // File of interest
+    psAssert (file, "missing file?");
+
+    pmReadout *readout = pmFPAviewThisReadout(view, file->fpa);
+    psAssert (readout, "missing readout?");
+
+    pmDetections *detections = psMetadataLookupPtr (&status, readout->analysis, "PSPHOT.DETECTIONS");
+    psAssert (detections, "missing detections?");
+
+    psArray *sources = detections->allSources;
+    psAssert (sources, "missing sources?");
+
+    static int npass;
+    char filename[64];
+    snprintf (filename, 64, "mags.%d.dat", npass);
+    FILE *ftest = fopen (filename, "w");
+    for (int j = 0; j < sources->n; j++) {
+	pmSource *source = sources->data[j];
+
+	float psfMag;
+	status = pmSourcePhotometryModel (&psfMag, NULL, source->modelPSF);
+
+	float psfMagNorm;
+	float Io = source->modelPSF->params->data.F32[PM_PAR_I0];
+	source->modelPSF->params->data.F32[PM_PAR_I0] = 1.0;
+	status = pmSourcePhotometryModel (&psfMagNorm, NULL, source->modelPSF);
+	source->modelPSF->params->data.F32[PM_PAR_I0] = Io;
+
+	// double apTrend = pmTrend2DEval (psf->ApTrend, (float)source->peak->x, (float)source->peak->y);
+	fprintf (ftest, "%d %d %d  %f %f %f %f  %f %f\n", j, source->peak->x, source->peak->y, source->modelPSF->params->data.F32[PM_PAR_I0], source->modelPSF->params->data.F32[PM_PAR_SXX], source->modelPSF->params->data.F32[PM_PAR_SYY], source->modelPSF->params->data.F32[PM_PAR_SXY], psfMag, psfMagNorm);
+    }
+    fclose (ftest);
+    npass++;
+
+    return true;
+}
+# endif
+
 bool psphotReadout(pmConfig *config, const pmFPAview *view, const char *filerule) {
 
Index: trunk/psphot/src/psphotReadoutCleanup.c
===================================================================
--- trunk/psphot/src/psphotReadoutCleanup.c	(revision 33994)
+++ trunk/psphot/src/psphotReadoutCleanup.c	(revision 34086)
@@ -7,5 +7,5 @@
 
     // remove internal pmFPAfiles, if created
-    if (psErrorCodeLast() == PSPHOT_ERR_DATA) {
+    if (psErrorCodeLast() == (psErrorCode) PSPHOT_ERR_DATA) {
         psErrorStackPrint(stderr, "Error in the psphot readout analysis");
         psErrorClear();
Index: trunk/psphot/src/psphotSignificanceImage.c
===================================================================
--- trunk/psphot/src/psphotSignificanceImage.c	(revision 33994)
+++ trunk/psphot/src/psphotSignificanceImage.c	(revision 34086)
@@ -8,5 +8,4 @@
     float SIGMA_SMTH, NSIGMA_SMTH;
     bool status = false;
-    bool guess = false;
 
     // smooth the image and variance map
@@ -35,5 +34,4 @@
         SIGMA_SMTH  = 0.5*(fwhmMajor + fwhmMinor) / (2.0*sqrt(2.0*log(2.0)));
         NSIGMA_SMTH = psMetadataLookupF32 (&status, recipe, "PEAKS_SMOOTH_NSIGMA");
-        guess = false;
     } else {
         // if we do not know the FWHM, use the guess smoothing kernel supplied.
@@ -43,5 +41,4 @@
         NSIGMA_SMTH = psMetadataLookupF32 (&status, recipe, "PEAKS_SMOOTH_NSIGMA");
         PS_ASSERT (status, NULL);
-        guess = true;
     }
     // record the actual smoothing sigma
Index: trunk/psphot/src/psphotSourceFits.c
===================================================================
--- trunk/psphot/src/psphotSourceFits.c	(revision 33994)
+++ trunk/psphot/src/psphotSourceFits.c	(revision 34086)
@@ -224,14 +224,4 @@
     if (source->type == PM_SOURCE_TYPE_DEFECT) return false;
     if (source->type == PM_SOURCE_TYPE_SATURATED) return false;
-
-# define TEST_X -420.0
-# define TEST_Y 300.0
-   
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	fprintf (stderr, "test galaxy\n");
-    }
-
-# undef TEST_X
-# undef TEST_Y
 
     // set the radius based on the footprint (also sets the mask pixels)
@@ -513,11 +503,4 @@
     }
 
-# define TEST_X -540.0
-# define TEST_Y 540.0
-   
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	psTraceSetLevel("psModules.objects.pmPCM_MinimizeChisq", 5);
-    }
-
     float t1, t2, t4, t5;
     if (TIMING) { psTimerStart ("psphotFitPCM"); }
@@ -569,8 +552,4 @@
     }
 
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	psTraceSetLevel("psModules.objects.pmPCM_MinimizeChisq", 0);
-    }
-
     // psTraceSetLevel("psLib.math.psMinimizeLMChi2", 0);
     psFree (pcm);
@@ -578,7 +557,4 @@
     return model;
 }
-
-# undef TEST_X
-# undef TEST_Y
 
 // note that these should be 1/2n of the standard sersic index
@@ -603,11 +579,4 @@
     float xMin = NAN;
     float chiSquare[N_INDEX_GUESS];
-
-# define TEST_X -540.0
-# define TEST_Y 540.0
-   
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	psTraceSetLevel("psModules.objects.pmPCM_MinimizeChisq", 5);
-    }
 
     for (int i = 0; i < N_INDEX_GUESS; i++) {
@@ -635,8 +604,4 @@
     assert (iMin >= 0);
 
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	psTraceSetLevel("psModules.objects.pmPCM_MinimizeChisq", 0);
-    }
-
     model->flags = PM_MODEL_STATUS_NONE; // do not attempt to handle failures here, let the next iteration deal with it
     model->params->data.F32[PM_PAR_7] = 0.5/indexGuess[iMin];
@@ -666,8 +631,4 @@
     float xMin = NAN;
     float chiSquare[N_INDEX_GUESS];
-
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	psTraceSetLevel("psModules.objects.pmPCM_MinimizeChisq", 5);
-    }
 
     for (int i = 0; i < N_INDEX_GUESS; i++) {
@@ -701,8 +662,4 @@
     }
     assert (iMin >= 0);
-    
-    if ((fabs(source->peak->xf - TEST_X) < 5) && (fabs(source->peak->yf - TEST_Y) < 5)) {
-	psTraceSetLevel("psModules.objects.pmPCM_MinimizeChisq", 0);
-    }
 
     model->flags = PM_MODEL_STATUS_NONE; // do not attempt to handle failures here, let the next iteration deal with it
Index: trunk/psphot/test/tap_psphot_varmodel.pro
===================================================================
--- trunk/psphot/test/tap_psphot_varmodel.pro	(revision 33994)
+++ trunk/psphot/test/tap_psphot_varmodel.pro	(revision 34086)
@@ -2,85 +2,111 @@
 # -*-sh-*-
 
-# $KAPA = kapa -noX
-
-# PSF.CONVOLVE : if true, we insert delta functions (and optionally
-#                galaxies) and smooth the image with the psf model
-#                (uses a GAUSS regardless of the model). Note that
-#                PSF.CONVOLVE = T is faster than F, but (a) only
-#                allows Gauss models and (b) only yields quantized
-#                locations
-
-# config for ppImage to generate chip, mask, weight
-$ppImageConfig = -recipe PPIMAGE PPIMAGE_N
-$ppImageConfig = $ppImageConfig -Db BACKGROUND T
-$ppImageConfig = $ppImageConfig -Db CHIP.FITS T
-$ppImageConfig = $ppImageConfig -Db CHIP.MASK.FITS T
-$ppImageConfig = $ppImageConfig -Db CHIP.VARIANCE.FITS T
-$ppImageConfig = $ppImageConfig -Db BASE.FITS F
-$ppImageConfig = $ppImageConfig -Db VARIANCE.BUILD T
-$ppImageConfig = $ppImageConfig -Db PHOTOM F
-
-# basic options for the these images (filter, location, obstype)
-$BaseOptions = -type OBJECT -filter r -skymags 20.86 -ra 270.70 -dec -23.70 -pa 0.0
-$BaseOptions = $BaseOptions -Df PSASTRO:DVO.GETSTAR.MAX.RHO 50000.0
-
-# create an image with fake sources and insert the resulting cmf file into a dvodb
-$RefConfig = -camera SIMTEST 
-$RefConfig = $RefConfig -recipe PPSIM STACKTEST.MAKE 
-$RefConfig = $RefConfig -D PSASTRO:PSASTRO.CATDIR catdir.ref 
-$RefConfig = $RefConfig -Db PSF.CONVOLVE F
-
-# options for the reference image
-$RefOptions = $BaseOptions -exptime 100.0 
-$RefOptions = $RefOptions -seeing 1.0 
-$RefOptions = $RefOptions -D PSF.MODEL PS_MODEL_GAUSS 
-$RefOptions = $RefOptions -Df STARS.DENSITY 10.0 
-$RefOptions = $RefOptions -Df STARS.SIGMA.LIM 0.5
-
-# basic config for ppSim with randomly distributed stars and NO galaxies
-$RealConfig = -camera SIMTEST 
-$RealConfig = $RealConfig -recipe PPSIM STACKTEST.RUN 
-$RealConfig = $RealConfig -D PSASTRO:PSASTRO.CATDIR catdir.ref
-$RealConfig = $RealConfig -Db STARS.FAKE F
-$RealConfig = $RealConfig -Db STARS.REAL T 
-$RealConfig = $RealConfig -Db MATCH.DENSITY F 
-$RealConfig = $RealConfig -Db PSF.CONVOLVE F
-$RealConfig = $RealConfig -Df STARS.DENSITY 10.0
-$RealConfig = $RealConfig -Df STARS.SIGMA.LIM 2.5
-$RealConfig = $RealConfig -Db GALAXY.FAKE F 
-$RealConfig = $RealConfig -Db GALAXY.GRID F 
-
-# options for the repeated images
-$RealOptions = $BaseOptions -exptime 30.0
-  
-$ExtraOptions = -D PSF.MODEL PS_MODEL_GAUSS
-
-# sample alternate options:
-# $ppSimOptions = $FakeOptions -D PSF.MODEL PS_MODEL_PS1_V1
-# $ppSimOptions = $FakeOptions -Df PSF.ARATIO 1.2
-# $ppSimOptions = $FakeOptions -Df PSF.THETA +30.0
-# $ppSimOptions = $FakeOptions -D PSF.MODEL PS_MODEL_GAUSS
-
-list fwhm 
- 1.0 
- 1.1 
- 1.2 
- 1.5
+# This script includes a set of tests to demonstrate the dependence of the faint-end bias on the weighting scheme
+# We have 3 weighting schemes :
+# CONSTANT -- per-pixel weight is fixed (disadvantage: lower S/N, especially for higher sky?)
+# IMAGE_VAR - per-pixel weight is Poisson from image (disadvantage: faint-end bias)
+# MODEL_VAR - per-pixel weight is Poisson from model (disadvantage: 2 linear-fit passes)
+
+# Functions:
+# 
+# init  : initialize variables
+# mkref : generate a fake reference catalog in a DVO database
+# mkexp : generate a fake exposure from fake catalog and detrend it (saves basename.in.cmf & basename.fits)
+# runphot : run psphot on an exposure (saves basename.cmf)
+# ckchip.mags : generate a set of summary plots for the psphot analysis
+
+# I would like to produce a grid of tests:
+# sky (bright, middle, dark)
+# fwhm (1.0, 1.3, 1.6)
+# PSF_MODEL input (GAUSS PS1_V1)
+# PSF_MODEL apply (GAUSS PS1_V1)
+# variance mode: CONSTANT, IMAGE_VAR, MODEL_VAR
+
+macro ppsimtest
+  data $1
+  # sf1 : measured flux inserted in image
+  # sm2 : theoretical magnitude for star
+  read x 1 y 2 sf1 3 sm2 5 Io 12
+  set sm1 = -2.5*log(sf1)
+  set dsm = sm1 - sm2
+  lim -n 2 sm1 -0.2 0.2; clear; box; plot sm1 dsm
+end
+
+macro go.one
+  mkdir test
+
+  local sky fwhm psf_in psf_out
+
+  # mkref creates refimage.* and catdir.ref
+  file catdir.ref found
+  if (not($found))
+    mkref
+  end
+
+  $KAPA = kapa -noX
+  if (not($?RefConfig)) init
+
+  foreach sky 20.0
+    foreach fwhm 1.0
+      foreach psf_in PS1_V1
+
+        sprintf name "test/test.%02d.%02d.%s" $sky {10*$fwhm} $psf_in
+        mkexp $name $sky $fwhm $psf_in
+	data $name.dat
+	read fluxIn 3 MagPredIn 5
+	set MagRealIn = -2.5*log(fluxIn)
+	set dMagIn = MagRealIn - MagPredIn
+        
+        foreach psf_out GAUSS PS1_V1
+          foreach mode CONSTANT IMAGE_VAR MODEL_VAR
+            runphot $name $name.$psf_out.$mode "-D LINEAR_FIT_VARIANCE_MODE $mode -D PSF_MODEL PS_MODEL_$psf_out"
+            ckchip.mags $name.in.cmf $name.$psf_out.$mode.cmf $name.$psf_out.$mode 0.0
+          end
+        end
+      end
+    end
+  end
 end
 
 macro go
-
   mkdir test
 
-  $ExtraOptions = -D PSF.MODEL PS_MODEL_GAUSS
-  mkexp test/image.00 1.0
-  $ExtraOptions = -D PSF.MODEL PS_MODEL_PGAUSS
-  mkexp test/image.01 1.0
-  $ExtraOptions = -D PSF.MODEL PS_MODEL_PS1_V1
-  mkexp test/image.02 1.0
+  local sky fwhm psf_in psf_out
+
+  # mkref creates refimage.* and catdir.ref
+  file catdir.ref found
+  if (not($found))
+    mkref
+  end
+
+  $KAPA = kapa -noX
+  if (not($?RefConfig)) init
+
+  foreach sky 19.0 20.0 21.0
+    foreach fwhm 1.0 1.3 1.6
+      foreach psf_in GAUSS PS1_V1
+
+        sprintf name "test/test.%02d.%02d.%s" $sky {10*$fwhm} $psf_in
+        # mkexp $name $sky $fwhm $psf_in
+	data $name.dat
+	read fluxIn 3 MagPredIn 5
+	set MagRealIn = -2.5*log(fluxIn)
+	set dMagIn = MagRealIn - MagPredIn
+        
+        foreach psf_out GAUSS PS1_V1
+          foreach mode CONSTANT IMAGE_VAR MODEL_VAR
+            # runphot $name $name.$psf_out.$mode "-D LINEAR_FIT_VARIANCE_MODE $mode -D PSF_MODEL PS_MODEL_$psf_out"
+            ckchip.mags $name.in.cmf $name.$psf_out.$mode.cmf $name.$psf_out.$mode 0.0
+          end
+        end
+      end
+    end
+  end
 end
 
 # create a reference database of fake stars to be used by ppSim below
 macro mkref
+  if (not($?RefConfig)) init
+
   exec rm -rf catdir.ref
   exec rm -f refimage.fits
@@ -100,4 +126,29 @@
 # create a realistic distribution of fake stars, GAUSS PSF
 macro mkexp
+  if ($0 != 5)
+    echo "USAGE: mkexp basename sky fwhm psf_model"
+    break
+  end
+
+  local fwhm basename psf_model
+  $basename = $1
+  $sky = $2
+  $fwhm = $3
+  $psf_model = $4
+
+  $ExtraOptions = -D PSF.MODEL PS_MODEL_$psf_model
+
+  # create the raw image
+  echo ppSim -seeing $fwhm -skymags $sky -nx 3000 -ny 3000 $RealConfig $RealOptions $ExtraOptions $basename
+  exec ppSim -seeing $fwhm -skymags $sky -nx 3000 -ny 3000 $RealConfig $RealOptions $ExtraOptions $basename
+  exec /bin/mv -f $basename.cmf $basename.in.cmf
+
+  # create the chip output
+  echo ppImage $ppImageConfig -file $basename.fits $basename
+  exec ppImage $ppImageConfig -file $basename.fits $basename
+end
+
+# create a realistic distribution of fake stars, GAUSS PSF
+macro mkexp.deep
   if ($0 != 3)
     echo "USAGE: mkexp basename fwhm"
@@ -109,7 +160,35 @@
   $fwhm = $2
 
+  $RealOptionsDeep = $BaseOptions -exptime 100
+
   # create the raw image
-  echo ppSim -seeing $fwhm -nx 3000 -ny 3000 $RealConfig $RealOptions $ExtraOptions $basename
-  exec ppSim -seeing $fwhm -nx 3000 -ny 3000 $RealConfig $RealOptions $ExtraOptions $basename
+  echo ppSim -seeing $fwhm -nx 3000 -ny 3000 $RealConfig $RealOptionsDeep $ExtraOptions $basename
+  exec ppSim -seeing $fwhm -nx 3000 -ny 3000 $RealConfig $RealOptionsDeep $ExtraOptions $basename
+  exec /bin/mv -f $basename.cmf $basename.in.cmf
+
+  # create the chip output
+  echo ppImage $ppImageConfig -file $basename.fits $basename
+  exec ppImage $ppImageConfig -file $basename.fits $basename
+end
+
+# create a realistic distribution of fake stars, GAUSS PSF
+macro mkexp.bright
+  if ($0 != 3)
+    echo "USAGE: mkexp basename fwhm"
+    break
+  end
+
+  local fwhm basename
+  $basename = $1
+  $fwhm = $2
+
+  # basic options for the these images (filter, location, obstype)
+  $BaseOptions = -type OBJECT -filter r -skymags 20.0 -ra 270.70 -dec -23.70 -pa 0.0
+  $BaseOptions = $BaseOptions -Df PSASTRO:DVO.GETSTAR.MAX.RHO 50000.0
+  $RealOptionsDeep = $BaseOptions -exptime 100
+
+  # create the raw image
+  echo ppSim -seeing $fwhm -nx 3000 -ny 3000 $RealConfig $RealOptionsDeep $ExtraOptions $basename
+  exec ppSim -seeing $fwhm -nx 3000 -ny 3000 $RealConfig $RealOptionsDeep $ExtraOptions $basename
   exec /bin/mv -f $basename.cmf $basename.in.cmf
 
@@ -133,4 +212,109 @@
   echo psphot -threads 4 -file $basename.ch.fits -mask $basename.ch.mk.fits -variance $basename.ch.wt.fits $outname $options
   exec psphot -threads 4 -file $basename.ch.fits -mask $basename.ch.mk.fits -variance $basename.ch.wt.fits $outname $options
+end
+
+# compare two cmf files with extname Chip.psf 
+# things to compare:
+# * completeness (which sources in (1) are not detected in (2)
+# * positions (X_PSF, Y_PSF) 
+# * instrumental psf mags
+# * position errors (no input errors; use a model?)
+# * measured FWHM?
+# * kron mags (fluxes)
+# * etc, etc
+macro ckchip.mags
+  if ($0 != 5)
+    echo "USAGE: ckchip.mags (raw) (out) (output) (zpt_off)"
+    break
+  end
+
+list pairs
+  PSF_INST_MAG_out      M_raw                 PSF_INST_MAG_raw 2 -0.21 0.21 V
+  AP_MAG_out            M_raw                 PSF_INST_MAG_raw 2 -0.21 0.21 V
+end
+
+  load.cmf $1 Chip.psf raw
+  load.cmf $2 Chip.psf out
+
+  # images generated with convolution will not have the right output positions
+  set X_raw = int(X_PSF_raw) + 0.5
+  set Y_raw = int(Y_PSF_raw) + 0.5
+  set M_raw = PSF_INST_MAG_raw + $4
+  set K_out = -2.5*log(KRON_FLUX_out)
+  match2d X_PSF_out Y_PSF_out X_PSF_raw Y_PSF_raw 1.5 -index1 index1 -index2 index2
+
+  local i NX NY nx ny N
+
+  resize 1000 1000
+
+  clear
+  section a0 0.0 0.0 1.0 0.5
+  label -fn courier 14; 
+  style -pt 0 -sz 0.4
+  show.pair 0
+  reindex ap = AP_MAG_out using index1
+  set dap = ap - v2
+  plot -c red -pt 2 -sz 0.5 rv dap
+
+  delete -q imag_V dmag_V smag_V Dmag_V dmag_Vraw
+  for imag -11 -6 0.2
+    subset dmsub = delta if (rv > $imag) && (rv < $imag + 0.2)
+    vstat -q dmsub
+    concat $imag imag_V
+    concat $MEAN dmag_V
+    concat $MEDIAN Dmag_V
+    concat $SIGMA smag_V
+  end
+
+  vstat -q dmag_V
+  $offset = $MEDIAN
+  set dmag_V = dmag_V - $offset
+  set Dmag_V = Dmag_V - $offset
+
+  section a1 0.0 0.50 1.0 0.25
+  lim rv -0.025 0.075; label -fn courier 14; box; 
+  # plot -c black -pt 0 -sz 0.3 MagPredIn dMagIn
+  plot -c red   -pt 7 -sz 2.0 imag_V dmag_V
+  plot -c darkgreen -pt 3 -sz 2.0 imag_V Dmag_V
+  # plot -c gold -pt 4 -sz 2.0 imag_V dmag_Vraw
+  plot -c blue  -pt 2 -sz 2.0 imag_V smag_V
+  # label -y "mean (red), median (green), unclipped mean (gold), sigma (blue) of delta"
+  label -y "mean (red), median (green), sigma (blue) of delta"
+  sprintf line "OFFSET: %6.3f" $offset
+  textline -frac 0.1 0.8 -fn courier 24 "$line"
+
+  subset dmsub = delta if (rv < -13) && (rv > -16)
+  vstat -q dmsub
+  sprintf line "STDEV: %6.3f" $SIGMA
+  textline -frac 0.1 0.7 -fn courier 24 "$line"
+
+
+  set lChiNorm = log(PSF_CHISQ_out / PSF_NDOF_out)
+  reindex chi = lChiNorm using index1
+  section a2 0.0 0.75 1.0 0.25
+  label -fn courier 14; 
+  lim rv chi; box; 
+  plot -c red -pt 0 -sz 0.5 rv chi
+
+  label -y "chisq"
+  png -name $3.png
+
+  # section a1 0.0 0.5 1.0 0.5
+  # style -pt 0 -sz 0.4
+  # show.pair 1
+end
+
+macro go.phot
+ runphot test.00 test.00.varmode.C "-Db SAVE.RESID T -D LINEAR_FIT_VARIANCE_MODE CONSTANT"
+ runphot test.00 test.00.varmode.I "-Db SAVE.RESID T -D LINEAR_FIT_VARIANCE_MODE IMAGE_VAR"
+ runphot test.00 test.00.varmode.M "-Db SAVE.RESID T -D LINEAR_FIT_VARIANCE_MODE MODEL_VAR"
+ runphot test.00 test.00.varmode.S "-Db SAVE.RESID T -D LINEAR_FIT_VARIANCE_MODE MODEL_SKY"
+end
+
+macro go.vars
+ dev -n varC; ckchip.mags test.00.in.cmf test.00.varmode.C.cmf test.00.varmode.C 0.0
+ dev -n varI; ckchip.mags test.00.in.cmf test.00.varmode.I.cmf test.00.varmode.I 0.0
+ dev -n varM; ckchip.mags test.00.in.cmf test.00.varmode.M.cmf test.00.varmode.M 0.0
+ dev -n varS; ckchip.mags test.00.in.cmf test.00.varmode.S.cmf test.00.varmode.S 0.0
 end
 
@@ -347,5 +531,6 @@
     lim rv $word:4 $word:5; box; plot rv delta
   end
-  label -y '$word:0' -x '$word:2'
+  $line = '$word:0' - '$word:1'
+  label -y "$line" -x '$word:2'
 end
 
@@ -637,4 +822,71 @@
 end
 
+macro init
+  # config for ppImage to generate chip, mask, weight
+  $ppImageConfig = -recipe PPIMAGE PPIMAGE_N
+  $ppImageConfig = $ppImageConfig -Db BACKGROUND T
+  $ppImageConfig = $ppImageConfig -Db CHIP.FITS T
+  $ppImageConfig = $ppImageConfig -Db CHIP.MASK.FITS T
+  $ppImageConfig = $ppImageConfig -Db CHIP.VARIANCE.FITS T
+  $ppImageConfig = $ppImageConfig -Db BASE.FITS F
+  $ppImageConfig = $ppImageConfig -Db VARIANCE.BUILD T
+  $ppImageConfig = $ppImageConfig -Db PHOTOM F
+  
+  # basic options for the these images (filter, location, obstype)
+  $BaseOptions = -type OBJECT -filter r -ra 270.70 -dec -23.70 -pa 0.0
+  $BaseOptions = $BaseOptions -Df PSASTRO:DVO.GETSTAR.MAX.RHO 50000.0
+  
+  # PSF.CONVOLVE : if true, we insert delta functions (and optionally
+  #                galaxies) and smooth the image with the psf model
+  #                (uses a GAUSS regardless of the model). Note that
+  #                PSF.CONVOLVE = T is faster than F, but (a) only
+  #                allows Gauss models and (b) only yields quantized
+  #                locations
+
+  # create an image with fake sources and insert the resulting cmf file into a dvodb
+  $RefConfig = -camera SIMTEST 
+  $RefConfig = $RefConfig -recipe PPSIM STACKTEST.MAKE 
+  $RefConfig = $RefConfig -D PSASTRO:PSASTRO.CATDIR catdir.ref 
+  $RefConfig = $RefConfig -Db PSF.CONVOLVE F
+  
+  # options for the reference image
+  $RefOptions = $BaseOptions
+  $RefOptions = $RefOptions -exptime 100.0 
+  $RefOptions = $RefOptions -seeing 1.0 
+  $RefOptions = $RefOptions -skymags 21.0  
+  $RefOptions = $RefOptions -D PSF.MODEL PS_MODEL_GAUSS 
+  $RefOptions = $RefOptions -Df STARS.DENSITY 10.0 
+  $RefOptions = $RefOptions -Df STARS.SIGMA.LIM 0.5
+
+  # basic config for ppSim with randomly distributed stars and NO galaxies
+  $RealConfig = -camera SIMTEST 
+  $RealConfig = $RealConfig -recipe PPSIM STACKTEST.RUN 
+  $RealConfig = $RealConfig -D PSASTRO:PSASTRO.CATDIR catdir.ref
+  $RealConfig = $RealConfig -Db STARS.FAKE F
+  $RealConfig = $RealConfig -Db STARS.REAL T 
+  $RealConfig = $RealConfig -Db MATCH.DENSITY F 
+  $RealConfig = $RealConfig -Db PSF.CONVOLVE F
+  $RealConfig = $RealConfig -Df STARS.DENSITY 10.0
+  $RealConfig = $RealConfig -Df STARS.SIGMA.LIM 1.0
+  $RealConfig = $RealConfig -Db GALAXY.FAKE F 
+  $RealConfig = $RealConfig -Db GALAXY.GRID F 
+  
+  # options for the repeated images
+  $RealOptions = $BaseOptions -exptime 30.0
+    
+  # sample alternate options:
+  # $ppSimOptions = $FakeOptions -D PSF.MODEL PS_MODEL_PS1_V1
+  # $ppSimOptions = $FakeOptions -Df PSF.ARATIO 1.2
+  # $ppSimOptions = $FakeOptions -Df PSF.THETA +30.0
+  # $ppSimOptions = $FakeOptions -D PSF.MODEL PS_MODEL_GAUSS
+  
+  list fwhm 
+   1.0 
+   1.1 
+   1.2 
+   1.5
+  end
+end
+
 if ($SCRIPT)
   fulltest 4