splat.F File Reference

Compute latitude functions. More...

Go to the source code of this file.

Functions/Subroutines
subroutine	splat (IDRT, JMAX, SLAT, WLAT)
	Computes cosines of colatitude and Gaussian weights for one of the following specific global sets of latitudes. More...

Detailed Description

Compute latitude functions.

Program History Log

Date	Programmer	Comments
96-02-20	IREDELL	Initial.
97-10-20	IREDELL	Adjust precision.
98-06-11	IREDELL	Generalize precision using FORTRAN 90 intrinsic.
1998-12-03	IREDELL	Generalize precision further.
1998-12-03	IREDELL	Uses AIX ESSL BLAS calls.
2009-12-27	DSTARK	Updated to switch between ESSL calls on an AIX platform, and Numerical Recipies calls elsewise.
2010-12-30	SLOVACEK	Update alignment so preprocessor does not cause compilation failure.
2012-09-01	E.Mirvis & M.Iredell	Merging & debugging linux errors of _d and _8 using generic LU factorization.
2012-11-05	E.Mirvis	Generic FFTPACK and LU lapack were removed.

Author

IREDELL

Date

96-02-20

Definition in file splat.F.

Function/Subroutine Documentation

splat()

subroutine splat	(		IDRT,
			JMAX,
		real, dimension(jmax)	SLAT,
		real, dimension(jmax)	WLAT
	)

Computes cosines of colatitude and Gaussian weights for one of the following specific global sets of latitudes.

• Gaussian latitudes (IDRT=4)
• Equally-spaced latitudes including poles (IDRT=0)
• Equally-spaced latitudes excluding poles (IDRT=256)

The Gaussian latitudes are located at the zeroes of the Legendre polynomial of the given order. These latitudes are efficient for reversible transforms from spectral space. (About twice as many equally-spaced latitudes are needed.) The weights for the equally-spaced latitudes are based on Ellsaesser (JAM,1966). (No weight is given the pole point.) Note that when analyzing grid to spectral in latitude pairs, if an equator point exists, its weight should be halved. This version invokes the ibm essl matrix solver.

Parameters

	IDRT	grid identifier IDRT=4 for Gaussian grid IDRT=0 for equally-spaced grid including poles IDRT=256 for equally-spaced grid excluding poles
	JMAX	number of latitudes
[out]	SLAT	sines of latitude
[out]	WLAT	Gaussian weights

Author

IREDELL

Date

96-02-20

Definition at line 44 of file splat.F.

References lubksb(), and ludcmp().

Referenced by sptranf0().