iraf.net

NUMBER:	247
MODULE:	photcal.fitparams
SYSTEM:	V2.10
DATE:	Mon Jun 13 16:12:33 MST 1994
FROM:	davis

BUG:	If the fitparams task parameter weighting is set to 'photometric'
	or 'equations', the addscatter parameter is set to 'yes', and
	either the number of parameters to be fit equals the number of data
	points, or the fit has no scatter, fitparams will crash with a
	floating operand error. This occurs because the expression used
	to estimate the additional scatter to be added to the weights in the
	next iteration of the fit goes to 0 in the denominator, causing a
	divide by zero error.

STATUS: The bug is fixed in 2.11. The workaround is to set weighting to
	'uniform' or set the addscatter parameter to 'no'.