Function:     irim_active

Purpose:      determine active detectors from a snip_det list

Category:     IRAS, private to program: IMAGE

Author:       Do Kester		do@guspace.rug.nl

Use:
int irim_active(
	int		scannr,
	list_type	*list,
	int		*lnr,
	int		*dlist,
	int		*nd )

returns: whether or not (some detectors of) this snip must be processed.

      LIST is an ordered list of reals,  where the integer part denotes
      a scan number and the fractional part are detector numbers as
      in IRAS-ES p.II-12&13.
      irim_active checks the LIST from position LNR onward for an integral
      part equal SCANNR. The fractional part is added / subtracted to
      DLIST in the right position. If complement is false and snip_det
      has no fractional part then DLIST is reset to all zero's,
      i.e. no detectors remain in DLIST.
      Example:
      LIST = ( 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22 ) & SCANNR = 0
      if ( complement ): DLIST will be the first row of detectors of band 2
      else	       : DLIST will be the last row of detectors of band 2
      NOTE: dead detectors can not be included in DLIST, as they
	    cannot be in LIST; small detectors, however, can.

Comment:      This routine is not callable in FORTRAN

Updates:      15 Aug 1991: DK, Creation date
	      04 Jun 1992: DK, prepared for GIPSY library

Original:     IMDETS
	Structured and translated by ASSISTANT II Plus, v1.2