Index: /trunk/ppStack/README.txt
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--- /trunk/ppStack/README.txt	(revision 15279)
+++ /trunk/ppStack/README.txt	(revision 15279)
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+ppStack needs to be optimised, principally to reduce the memory
+footprint (10 or so images will get it to over 4 GB).  The proposed
+strategy follows, more or less, the same as for ppMerge.
+
+* Convolution steps:
+  - For each file:
+    + read entire image
+    + convolve to reference PSF
+    + write convolved image
+
+* Combination step:
+  - For each chunk:
+    + For each file, read chunk
+    + combine chunk
+  - Probably have to repeat, to do the multi-pass rejection
+
+
+To do:
+* Need file PPSTACK.OUTPUT.CONV (image, mask, weight versions)
+* Need file PPSTACK.INPUT.CONV (image, mask, weight versions)
+* Check: does pmFPAfileChecks do piece-by-piece read?
+* Can we reset a file, so that we can read it twice through?
+* pmStack functions probably need work so that they operate on a piece
+  of the image at a time.  Will there be issues with the masks in the
+  second pass?