SUBROUTINE ZMERG1(FLUX,WAVE,MASK,NPTS,TOTAL,NADDS,NBINS,
     *                  WFIRST,DELW,STATUS)
*
* Module Number: 13.10.1.1
*
* Module Name: zmerg1
*
* Keyphrase:
* ----------
*       Merge data into equally spaced wavelength bins
*
* Description:
* ------------
*       Data, specified by a wavelength, flux, and mask vector are placed
*       into equally spaced bins in a total vector.  Bins are specified
*       by a starting wavelength and a delta wavelength.  The number of
*       adds to each bin is kept.
*
* Fortran Name: zmerg1.for
*
* Keywords of accessed files and tables:
* --------------------------------------
*       none
*
* Subroutines called:
* -------------------
* SDAS:
*       UMSPUT
*
* History:
* --------
* version         Date            Author                Description
*    1          02-27-87        D. Lindler      Designed and coded
*
*-----------------------------------------------------------------------------
*
C     INCLUDE FILE FOR THE IRAF77 FORTRAN INTERFACE TO THE IRAF VOS
C
C
C     FILE I/O ACCESS MODES
C
      INTEGER   RDONLY
      PARAMETER (RDONLY = 1)
      INTEGER   RDWRIT
      PARAMETER (RDWRIT = 2)
      INTEGER   WRONLY
      PARAMETER (WRONLY = 3)
      INTEGER   APPEND
      PARAMETER (APPEND = 4)
C
C     CODES FOR DATA TYPES
C
      INTEGER   TYBOOL
      PARAMETER (TYBOOL = 1)
      INTEGER   TYCHAR
      PARAMETER (TYCHAR = 2)
      INTEGER   TYINT
      PARAMETER (TYINT = 4)
      INTEGER   TYREAL
      PARAMETER (TYREAL = 6)
      INTEGER   TYDOUB
      PARAMETER (TYDOUB = 7)
C
C     UMSPUT DESTINATIONS -- CB, DAO, 4-SEP-87
C
      INTEGER STDOUT
      PARAMETER (STDOUT = 1)
      INTEGER STDERR
      PARAMETER (STDERR = 2)
C
C     UHDAS HEADER PARM TYPES -- CB, DAO, 5-SEP-87
C
      INTEGER GENHDR
      PARAMETER (GENHDR = 0)
      INTEGER IMSPEC
      PARAMETER (IMSPEC = 1)
C
C     THIS SECTION IS FOR PARAMETERS RELEVANT TO TABLE I/O.
C
C     THESE MAY BE SET BY UTPPTI AND/OR READ BY UTPGTI:
C
C                                       LENGTH OF ROW (UNIT = SIZE OF REAL)
      INTEGER   TBRLEN
      PARAMETER (TBRLEN = 1)
C                                       INCREASE ROW LENGTH
      INTEGER   TBIRLN
      PARAMETER (TBIRLN = 2)
C                                       NUMBER OF ROWS TO ALLOCATE
      INTEGER   TBALLR
      PARAMETER (TBALLR = 3)
C                                       INCREASE ALLOC NUM OF ROWS
      INTEGER   TBIALR
      PARAMETER (TBIALR = 4)
C                                       WHICH TYPE OF TABLE? (ROW OR COLUMN)
      INTEGER   TBWTYP
      PARAMETER (TBWTYP = 5)
C                                       MAXIMUM NUMBER OF USER PARAMETERS
      INTEGER   TBMXPR
      PARAMETER (TBMXPR = 6)
C                                       MAXIMUM NUMBER OF COLUMNS
      INTEGER   TBMXCL
      PARAMETER (TBMXCL = 7)
C                                       TYPE = ROW-ORDERED TABLE
      INTEGER   TBTYPR
      PARAMETER (TBTYPR = 11)
C                                       TYPE = COLUMN-ORDERED TABLE
      INTEGER   TBTYPC
      PARAMETER (TBTYPC = 12)
C
C     THESE MAY BE READ BY UTPGTI BUT MAY NOT BE SET:
C
C                                       NUMBER OF ROWS WRITTEN TO
      INTEGER   TBNROW
      PARAMETER (TBNROW = 21)
C
C     END IRAF77.INC
*
* Input parameters
*
*       FLUX - flux vector (REAL*8)
*       WAVE - wavelength vector (real*8)
*       MASK - mask vector (REAL*8)
*       NPTS - number of points in FLUX, WAVE, MASK (integer)
*       TOTAL - vector of binned flux values (REAL*8)
*       NADDS - vector giving number of adds to each point in TOTAL (integer)
*       NBINS - number of bins in TOTAL and NADDS (integer)
*       WFIRST - starting wavelength (REAL*8)
*       DELW - bin size (REAL*8)
*
* Output parameters
*
*       TOTAL,NADDS - updated vectors
*       STATUS  error status (integer)
*
        DOUBLE PRECISION FLUX(1),MASK(1),TOTAL(1),WFIRST,DELW
        DOUBLE PRECISION WAVE(1)
        INTEGER NADDS(1),NPTS,NBINS
        INTEGER STATUS
*
* Local variables
*
*                                       -- BIN NUMBER
        INTEGER BIN
*                                       -- INDEX
        INTEGER I,ISTAT
        CHARACTER*130   CONTXT
*-------------------------------------------------------------------------------
C
C LOOP ON POINTS IN INPUTS
C
        DO 100 I=1,NPTS
C
C CHECK IF MASK SAYS TO USE IT
C
                IF(MASK(I).GT.0.0)THEN
C
C COMPUTE BIN NUMBER
C
                        BIN=(WAVE(I)-WFIRST)/DELW
C
C CHECK IF VALID BIN NUMBER
C
                        IF((BIN.LE.0).OR.(BIN.GT.NBINS))THEN
                          CONTXT='INVALID WAVELENGTH FOR THE GRATING'
                          GO TO 999
                        ENDIF
C
C UPDATE BIN
C
                        TOTAL(BIN)=TOTAL(BIN)+FLUX(I)
                        NADDS(BIN)=NADDS(BIN)+1
                ENDIF
100     CONTINUE
        STATUS=0
        GO TO 1000
999     CALL UMSPUT(CONTXT,STDOUT+STDERR,0,ISTAT)
1000    RETURN
        END