W3FT38

The W3FT38 routine computes 2.5 x 2.5 N. Hemi. grid of
           145 x 37 points from spectral coefficients in a
           Rhomboidal 30 resolution representing a scaler field.

USAGE:  CALL W3FT38(FLN,GN,PLN,FL,WORK,TRIGS)

   Input variables:
      FLN        961 COMPLEX COEFF.
      PLN        (32,31,37) REAL SPACE WITH LEGENDRE POLYNOMIALS
	         COMPUTED BY W3FA12.
      FL         31 COMPLEX SPACE FOR FOURIER COEFF.
      WORK       144 REAL WORK SPACE FOR SUBR. W3FT12
      TRIGS      216 PRECOMPUTED TRIG FUNCS. USED
	         IN W3FT12, COMPUTED BY W3FA13

   Output variables:
      GN         (145,37) GRID VALUES.
	         5365 POINT GRID IS TYPE 29 OR 1D HEX O.N. 84

REMARKS:
     MEMORY, IT WAS NOT OPTIMIZED FOR SPEED, 70 PERCENT OF THE TIME WAS
     USED BY SUBROUTINE W3FA12 COMPUTING THE LEGENDRE POLYNOMIALS. SINCE
     THE LEGENDRE POLYNOMIALS ARE CONSTANT THEY NEED TO BE COMPUTED
     ONLY ONCE IN A PROGRAM. BY MOVING W3FA12 TO THE MAIN PROGRAM AND
     COMPUTING PLN AS A (32,31,37) ARRAY AND CHANGING THIS SUBROUTINE
     TO USE PLN AS A THREE DIMENSION ARRAY THE RUNNING TIME WAS CUT
     70 PERCENT. ADD FOLLOWING CODE TO MAIN PROGRAM TO COMPUTE EPS, PLN,
     TRIGS, AND RCOS ONE TIME IN PROGRAM.

 
W3lib.tar Library contains Fortran 90 decoder/encoder routines for GRIB edition 1. (Fortran90)
Date posted: 2/22/2007