w3fi58.f File Reference

Pack positive differences in least bits. More...

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Functions/Subroutines
subroutine	w3fi58 (ifield, npts, nwork, npfld, nbits, len, kmin)
	Converts an array of integer numbers into an array of positive differences (number(s) - minimum value) and packs the magnitude of each difference right-adjusted into the least number of bits that holds the largest difference.

Detailed Description

Pack positive differences in least bits.

Author

Robert Allard

Date

1987-09-02

Definition in file w3fi58.f.

Function/Subroutine Documentation

w3fi58()

subroutine w3fi58	(	integer, dimension(*)	ifield,
			npts,
		integer, dimension(*)	nwork,
		character*1, dimension(*)	npfld,
			nbits,
			len,
			kmin
	)

Converts an array of integer numbers into an array of positive differences (number(s) - minimum value) and packs the magnitude of each difference right-adjusted into the least number of bits that holds the largest difference.

Program history log:

• Robert Allard 1987-09-02
• Ralph Jones 1988-10-02 Converted to cdc cyber 205 ftn200 fortran.
• Ralph Jones 1990-05-17 Converted to cray cft77 fortran.
• Ralph Jones 1990-05-18 Change name vbimpk to w3lib name w3fi58()
• Mark Iredell 1996-05-14 Generalized computation of nbits.
• Ebisuzaki 1998-06-30 Linux port.

Parameters

[in]	IFIELD	Array of integer data for processing.
[in]	NPTS	Number of data values to process in IFIELD (and nwork) where, npts > 0.
[out]	NWORK	Work array with integer difference
[out]	NPFLD	Array for packed data (character*1) (user is responsible for an adequate dimension.)
[out]	NBITS	Number of bits used to pack data where, 0 < nbits < 32 (the maximum difference without overflow is 2**31 -1)
[out]	LEN	Number of packed bytes in npfld (set to 0 if no packing) where, len = (nbits * npts + 7) / 8 without remainder
[out]	KMIN	Minimum value (subtracted from each datum). If this packed data is being used for grib data, the programer will have to convert the KMIN value to an IBM370 32 bit floating point number.

Note

LEN = 0, NBITS = 0, and no packing performed if

• (1) KMAX = KMIN (a constant field)
• (2) NPTS < 1 (see input argument)

Author

Robert Allard

Date

1987-09-02

Definition at line 38 of file w3fi58.f.