W3FT11

The W3FT11 routine computes 2.5 x 2.5 S. hemi. grid
           of 145 x 37 points from spectral coefficients in 
           a rhomboidal 30 resolution representing a vector field.

USAGE:  CALL W3FT11(VLN,GN,PLN,EPS,FL,WORK,TRIGS,RCOS)

   Input variables:
      VLN       992 COMPLEX COEFF.
      PLN       992 REAL SPACE FOR LEGENDRE POLYNOMIALS.
      EPS       992 REAL SPACE FOR
                COEFFS. USED IN COMPUTING PLN.
      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
      RCOS      37 RECIPROCAL COSINE LATITUDES OF
                2.5 X 2.5 GRID MUST BE COMPUTED BEFORE
                FIRST CALL TO W3FT11 USING SUBR. W3FA13.
  
   Output variables:
      GN        (145,37) GRID VALUES.
                5365 POINT GRID IS TYPE 30 OR 1E HEX O.N. 84
 
REMARKS:
    THIS SUBROUTINE WAS OPTIMIZED TO RUN IN A SMALL AMOUNT OF
    MEMORY, IT IS NOT OPTIMIZED FOR SPEED, 70 PERCENT OF THE TIME IS
    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 YOU CAN CUT THE RUNNING TIME
    70 PERCENT.

 


  
W3lib.tar
  
Library contains Fortran 90 decoder/encoder
   routines for GRIB edition 1. (Fortran90) 

   Date posted: 2/22/2007