SUM

        SUM

    This program is used to sum many images,  handling  a  weight  image  in
    order to produce the average image later on.
              It computes     X(i,j) = X(i,j) + F * Z(i,j)
              and             Y(i,j) = Y(i,j) + F
    for  all  non  blanked  pixels  of  the  input  image  Z.   When  called
    repetitively  with  the same input/output images X and Y, X contains the
    weighted sum of all Z images, and  Y  the  weight  of  each  pixels.   A
    parameter is provided to initialise the process.

    The last step to obtain the average image is to  divide  X  by  Y  using
    program COMBINE with option DIVIDE.  You can also use SIC command LET to
    do so, but SUM and COMBINE will handle properly blanking values.

    This is a quick reference about  all  programs   available   under   the
    GILDAS  package.   It may not be up to date, and not all listed programs
    are fully debugged.

    For  convenience,  this  is  a   thematic   summary   in   which    some
    algorithms may appear more than one time.
    * GFITS *     * GRAPHIC *   * MAPPING *   * VECTOR *
    BACKGROUND    BLANKING      CIRCLE        CLEAN-C
    CLEAN         COMBINE       COMPRESS      CONVERT
    CORRELATE     CV_SMOOTH     DG_SMOOTH     EXAMPLE
    EXAMPLE1      EXPAND        EXTRACT       FIELD_FIND
    FIELD_LIST    FIELD_STAT    FILL_CUBE     FITS_GILDAS
    FLOW          FOURIER       GAUSS_1D      GAUSS_2D
    GAUSS_SMOOTH  GILDAS_FITS   GRID_CUBE     GRID_EXTEND
    GRID_PROJECT  GRID_SG       HEADER        HISTO_CLOUD
    HISTO_CROSS   HISTO_DOUBLE  HISTO_SIMPLE  HISTO_TABLE
    IMAGE         INTERPOLATE   LIST          MAKE_BACK
    MAKE_CUBE     MAKE_MOSAIC   MAKPLAN       MANDEL
    MANDEL_REAL   MAP_AVER      MAP_COMPRESS  MAP_EXPAND
    MAP_INTER     MASK          MERGE         MINIMIZE
    MIX-C         MOSAIC        MOSAIC_CLEAN  MX
    NOISE_SMOOTH  ONOFF         OVERLAY       PLANE
    PLANE_OLD     PRIMARY       PSC           REGRESSION
    REGUL         REPROJECT     RESTORE       RGBTOPS
    SELF_CAL      SHIFT         SMOOTH        SORT
    SUM           SWAP          TABLE         TRANSPOSE
    TRUE_COLOR    UV_ASCAL      UV_AVERAGE    UV_CENTER
    UV_CIRCLE     UV_CLIP       UV_COMPRESS   UV_CRASH
    UV_DFT        UV_EXTRACT    UV_FIT-OLD    UV_FIT
    UV_FITC       UV_FLAG       UV_LIST       UV_MAP
    UV_MERGE      UV_MODEL      UV_NOISE      UV_SELFCAL
    UV_SHIFT      UV_SHORT      UV_SINGLE     UV_SUBTRACT
    UV_ZERO       UVMAP         UVSORT

    To access the following subtopic, type  (under  UNIX)  "EXPLAIN  SUMMARY
    subtopic"