iraf.net

NUMBER:	246
MODULE:	images.imcombine, ccdred.combine, onedspec$scombine
SYSTEM:	V2.10.2
DATE:	Mon Jun  6 17:03:15 MST 1994
FROM:	valdes

BUG:	In rare circumstances when using one of the clipping algorithms
	nkeep > 0 the task will not complete because it has entered
	a nonterminating loop.  This occurs when too many
	pixels are rejected and two or more rejected pixels have
	equal residuals the equal residual points are added back.
	However this is done within the iterative loop and after
	adding back the pixels the task finds there are now more than
	nkeep pixels and so repeats the loop with the same result.
	The work around is to change nkeep.  A change is likely
	to fix the specific case.  A value of zero for nkeep will
	avoid the problem entirely but with the possibility of
	rejecting all pixels.

STATUS:	The adding back of pixels should be done outside the iterative
	loop and this change has been made for the next release (V2.11).