Index: trunk/psphot/src/psphotStackChisqImage.c
===================================================================
--- trunk/psphot/src/psphotStackChisqImage.c	(revision 27547)
+++ trunk/psphot/src/psphotStackChisqImage.c	(revision 27657)
@@ -12,6 +12,8 @@
     psTimerStart ("psphot.chisq.image");
 
-    // create a holder for the image
-    pmReadout *chiImage = pmReadoutAlloc();
+    pmFPAfile *chisqFile = pmFPAfileSelectSingle(config->files, "PSPHOT.CHISQ.IMAGE", 0);
+    psAssert (chisqFile, "missing chisq image FPA?");
+
+    pmReadout *chiReadout = NULL;
 
     int num = psMetadataLookupS32 (&status, config->arguments, "PSPHOT.INPUT.NUM");
@@ -20,5 +22,5 @@
     // loop over the available readouts
     for (int i = 0; i < num; i++) {
-        if (!psphotStackChisqImageAddReadout(config, view, chiImage, "PSPHOT.INPUT", i)) {
+        if (!psphotStackChisqImageAddReadout(config, view, &chiReadout, "PSPHOT.INPUT", i)) {
             psError (PSPHOT_ERR_CONFIG, false, "failed to model background for PSPHOT.INPUT entry %d", i);
             return false;
@@ -26,5 +28,16 @@
     }
 
+    num = psMetadataLookupS32 (&status, config->arguments, "PSPHOT.INPUT.NUM");
+    psAssert (status, "programming error: must define PSPHOT.INPUT.NUM");
+
+    psMetadataAddS32(config->arguments, PS_LIST_TAIL, "PSPHOT.CHISQ.NUM", PS_META_REPLACE, "", num);
+    num++;
+    psMetadataAddS32(config->arguments, PS_LIST_TAIL, "PSPHOT.INPUT.NUM", PS_META_REPLACE, "", num);
+
     // need to save the resulting image somewhere (PSPHOT.INPUT?)
+    if (!psMetadataAddPtr(config->files, PS_LIST_TAIL, "PSPHOT.INPUT", PS_DATA_UNKNOWN | PS_META_DUPLICATE_OK, "", chisqFile)) {
+        psError(PM_ERR_CONFIG, false, "could not add chisqFPA to config files");
+        return false;
+    }
 
     psLogMsg ("psphot", PS_LOG_INFO, "built chisq image: %f sec\n", psTimerMark ("psphot.chisq.image"));
@@ -34,6 +47,6 @@
 
 bool psphotStackChisqImageAddReadout(const pmConfig *config, // Configuration
-				     pmFPAview *view,
-				     pmReadout *chiReadout,
+				     const pmFPAview *view,
+				     pmReadout **chiReadout,
 				     char *filename, 
 				     int index) 
@@ -49,10 +62,24 @@
 
     psImage *inImage     = inReadout->image;
+    psAssert (inImage, "missing image?");
+
     psImage *inVariance  = inReadout->variance;
+    psAssert (inVariance, "missing variance?");
+
     psImage *inMask      = inReadout->mask;
+    psAssert (inMask, "missing mask?");
 
-    psImage *chiImage    = chiReadout->image;
-    psImage *chiVariance = chiReadout->variance;
-    psImage *chiMask     = chiReadout->mask;
+    if (*chiReadout == NULL) {
+	*chiReadout = pmFPAGenerateReadout(config, view, "PSPHOT.CHISQ.IMAGE", input->fpa, NULL, 0);
+    }
+
+    psImage *chiImage = (*chiReadout)->image;
+    psAssert (chiImage, "missing chi image");
+
+    psImage *chiVariance = (*chiReadout)->variance;
+    psAssert (chiVariance, "missing chi variance");
+
+    psImage *chiMask = (*chiReadout)->mask;
+    psAssert (chiMask, "missing chi mask");
 
     // select the appropriate recipe information
@@ -83,2 +110,72 @@
     return true;
 }
+
+bool psphotStackRemoveChisqFromInputs (pmConfig *config) {
+
+    bool status = false;
+
+    int chisqNum = psMetadataLookupS32 (&status, config->arguments, "PSPHOT.CHISQ.NUM");
+    psAssert (status, "programming error: must define PSPHOT.CHISQ.NUM");
+
+    int inputNum = psMetadataLookupS32 (&status, config->arguments, "PSPHOT.INPUT.NUM");
+    psAssert (status, "programming error: must define PSPHOT.INPUT.NUM");
+
+    pmFPAfileRemoveSingle (config->files, "PSPHOT.INPUT", chisqNum);
+
+    inputNum --;
+    psMetadataAddS32(config->arguments, PS_LIST_TAIL, "PSPHOT.INPUT.NUM", PS_META_REPLACE, "", inputNum);
+
+    return true;
+}
+
+bool pmFPAfileRemoveSingle(psMetadata *files, const char *name, int num)
+{
+    PS_ASSERT_PTR_NON_NULL(files, NULL);
+    PS_ASSERT_INT_NONNEGATIVE(num, NULL);
+
+    psList* mdList = files->list;
+    psHash* mdHash = files->hash;
+
+    // Generate a REGEX to select only items that match 'name'
+    psString regex = NULL;              // Regular expression
+    if (name) {
+        if (!psMetadataLookup(files, name)) {
+            // No files match the requested name
+            return false;
+        }
+        psStringAppend(&regex, "^%s$", name);
+    }
+
+    psMetadataIterator *iter = psMetadataIteratorAlloc(files, PS_LIST_HEAD, regex); // Iterator
+    psFree(regex);
+    psMetadataItem *item;               // Item from iteration
+
+    bool found = false;
+    int i = 0;                          // Counter
+    for (i = 0; !found && (item = psMetadataGetAndIncrement(iter)); i++) {
+        if (i == num) found = true;
+    }
+    psFree(iter);
+    if (!found) {
+	return false;
+    }
+
+    char *key = item->name;
+
+    // look up the name via hash to see if we have a multi or not
+    psMetadataItem* hashItem = psHashLookup(mdHash, name);
+    if (hashItem == NULL) {
+        psError(PS_ERR_UNKNOWN, false, _("Failed to remove metadata item, %s, from metadata table."), key);
+        return false;
+    }
+
+    if (hashItem->type == PS_DATA_METADATA_MULTI) {
+        // multiple entries with same key, remove just the specified one
+        psListRemoveData(hashItem->data.list, item);
+    } else {
+        psHashRemove(mdHash, key);
+    }
+    psListRemoveData(mdList, item);
+
+    return true;
+}