iraf.net

MODULE: scopy, sarith, dohydra, dofibers, and possibly other onedspec tasks
SYSTEM: V2.10 - V2.10.4p1

NUMBER:	338
MODULE:	scopy, sarith, dohydra, dofibers, and possibly other onedspec tasks
SYSTEM:	V2.10 - V2.10.4p1
DATE:	Thu Apr 18 11:47:29 MST 1996
FROM:	valdes

BUG:	When working with 'multispec' format data (echelle data or
	multiple spectra with different dispersion functions as would
	occur if DISPCOR is used without linearizing the spectra to
	the same dispersion system) the SCOPY and SARITH task
	may fail with a floating point exception.  This is caused
	by use of an uninitialized array.  Because it depends on
	what values are in the array it can be sporatic.  It appears
	to be more likely to occur with the Dec/Alpha/OSF1 version.
	There are other tasks which may, in rare cases, also encounter
	this.  This will only  occur with tasks that are creating a new
	output spectrum.  The workarounds are to avoid cases with differing 
	dispersions in the same image such as by linearizing all
	spectra to the same dispersion function in multifiber or
	multislit data.  This particularly applies to using DOHYDRA and
	DOFIBERS with params.linearize=no.  For echelle data there is no
	good option other than to avoid having to use SCOPY/SARITH after
	dispersion calibration.

STATUS:	Fixed in later versions.