NAME

       reduce.c - Determines whether the number of groups should be increased in order to reduce the size of the
       large groups, and to make that adjustment.

SYNOPSIS

       #include 'grib2_int.h'
       #include <stdlib.h>

   Functions
       int reduce (g2int *kfildo, g2int *jmin, g2int *jmax, g2int *lbit, g2int *nov, g2int *lx, g2int *ndg,
           g2int *ibit, g2int *jbit, g2int *kbit, g2int *novref, g2int *ibxx2, g2int *ier)
           Determines whether the number of groups should be increased in order to reduce the size of the large
           groups, and to make that adjustment.

Detailed Description

       Determines whether the number of groups should be increased in order to reduce the size of the large
       groups, and to make that adjustment.

       Author
           Harry Glahn, The Meteorological Development Lab (MDL)

       Date
           November 2001

       Definition in file reduce.c.

Function Documentation

   int reduce (g2int * kfildo, g2int * jmin, g2int * jmax, g2int * lbit, g2int * nov, g2int * lx, g2int * ndg,
       g2int * ibit, g2int * jbit, g2int * kbit, g2int * novref, g2int * ibxx2, g2int * ier)
       Determines whether the number of groups should be increased in order to reduce the size of the large
       groups, and to make that adjustment. By reducing the size of the large groups, less bits may be necessary
       for packing the group sizes and all the information about the groups.

       The reference for nov was removed in the calling routine so that kbit could be determined. This furnishes
       a starting point for the iterations in reduce. However, the reference must be considered.

       PROGRAM HISTORY LOG

       • November 2001 Harry Glahn, The Meteorological Development Lab (MDL) tdl grib2

       • March 2002 Harry Glahn, The Meteorological Development Lab (MDL) comment ier = 715

       • March 2002 Harry Glahn, The Meteorological Development Lab (MDL) modified to accommodate lx=1 on entry

       DATA SET USE

       • kfildo - unit number for output (print) file. (output)

       Parameters
           kfildo unit number for output (print) file. (input)
           jmin  the  minimum of each group (j=1,lx). it is possible after splitting the groups, jmin() will not
           be the minimum of the new group. this doesn't matter;  jmin()  is  really  the  group  reference  and
           doesn't have to be the smallest value. (input/output)
           jmax the maximum of each group (j=1,lx). (input/output)
           lbit the number of bits necessary to pack each group (j=1,lx). (input/output)
           nov the number of values in each group (j=1,lx). (input/output)
           lx the number of groups. this will be increased if groups are split. (input/output)
           ndg the dimension of jmin(), jmax(), lbit(), and nov( ). (input)
           ibit the number of bits necessary to pack the jmin(j) values, j=1,lx. (input)
           jbit the number of bits necessary to pack the lbit(j) values, j=1,lx. (input)
           kbit the number of bits necessary to pack the nov(j) values, j=1,lx. if the groups are split, kbit is
           reduced. (input/output)
           novref reference value for nov(). (input)
           ibxx2 2**j (j=0,30). (input)
           ier error return. (output)

           • 0 = good return.

           • 714 = problem in algorithm. reduce aborted.

           • 715 = ngp not large enough. reduce aborted.

       Returns
           always returns 0, see parameter ier for error code.

        ntotbt(j) = the total bits used for the packing bits j
                              (j=1,30). (internal)
         nboxj(j) = new boxes needed for the packing bits j
                              (j=1,30). (internal)
                  newbox(l) = number of new boxes (groups) for each original
                              group (l=1,lx) for the current j. (automatic)
                              (internal)
                 newboxp(l) = same as newbox() but for the previous j.
                              this eliminates recomputation. (automatic)
                              (internal)
                      cfeed = contains the character representation
                              of a printer form feed. (character) (internal)
                      ifeed = contains the g2int value of a printer
                              form feed. (internal)
                     iorigb = the original number of bits necessary
                              for the group values. (internal)

       Author
           Harry Glahn, The Meteorological Development Lab (MDL)

       Date
           November 2001

       Definition at line 88 of file reduce.c.

       Referenced by pack_gp().

Author

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NCEPLIBS-g2c                                      Version 2.1.0                                      reduce.c(3)