Man page - reduce(3)

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Manual

reduce.c

NAME
SYNOPSIS
Functions
Detailed Description
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)
Author

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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