ungrib/src/ngl/w3/w3fi82.f

   1       SUBROUTINE W3FI82 (IFLD,FVAL1,FDIFF1,NPTS)
   2 C$$$  SUBPROGRAM DOCUMENTATION BLOCK
   3 C                .      .    .                                       .
   4 C SUBPROGRAM:  W3FI82        CONVERT TO SECOND DIFF ARRAY
   5 C   PRGMMR: CAVANAUGH        ORG: NMC421      DATE:93-08-18
   6 C
   7 C ABSTRACT: ACCEPT AN INPUT ARRAY, CONVERT TO ARRAY OF SECOND
   8 C   DIFFERENCES.  RETURN THE ORIGINAL FIRST VALUE AND THE FIRST
   9 C   FIRST-DIFFERENCE AS SEPARATE VALUES.
  10 C
  11 C PROGRAM HISTORY LOG:
  12 C   93-07-14  CAVANAUGH
  13 C   93-08-18  R.E.JONES   RECOMPILE FOR SiliconGraphics
  14 C   95-10-31  IREDELL     REMOVED SAVES AND PRINTS
  15 C
  16 C USAGE:    CALL W3FI82 (IFLD,FVAL1,FDIFF1,NPTS)
  17 C   INPUT ARGUMENT LIST:
  18 C     IFLD     - INTEGER INPUT ARRAY
  19 C     NPTS     - NUMBER OF POINTS IN ARRAY
  20 C
  21 C   OUTPUT ARGUMENT LIST:
  22 C     IFLD     - SECOND DIFFERENCED FIELD
  23 C     FVAL1    - FLOATING POINT ORIGINAL FIRST VALUE
  24 C     FDIFF1   -     "      "   FIRST FIRST-DIFFERENCE
  25 C
  26 C REMARKS: SUBPROGRAM CAN BE CALLED FROM A MULTIPROCESSING ENVIRONMENT.
  27 C
  28 C ATTRIBUTES:
  29 C   LANGUAGE: SiliconGraphics 3.5 FORTRAN 77
  30 C   MACHINE:  SiliconGraphics model 25, 35, INDIGO
  31 C
  32 C$$$
  33 C
  34       REAL        FVAL1,FDIFF1
  35 C
  36       INTEGER     IFLD(*),NPTS
  37 C
  38 C  ---------------------------------------------
  39           DO 4000 I = NPTS, 2, -1
  40               IFLD(I)  = IFLD(I) - IFLD(I-1)
  41  4000     CONTINUE
  42           DO 5000 I = NPTS, 3, -1
  43               IFLD(I)  = IFLD(I) - IFLD(I-1)
  44  5000     CONTINUE
  45 C         PRINT *,'IFLD(1) =',IFLD(1),'  IFLD(2) =',IFLD(2)
  46 C
  47 C                      SPECIAL FOR GRIB
  48 C                         FLOAT OUTPUT OF FIRST POINTS TO ANTICIPATE
  49 C                         GRIB FLOATING POINT OUTPUT
  50 C
  51           FVAL1    = IFLD(1)
  52           FDIFF1   = IFLD(2)
  53 C
  54 C       SET FIRST TWO POINTS TO SECOND DIFF VALUE FOR BETTER PACKING
  55 C
  56           IFLD(1)  = IFLD(3)
  57           IFLD(2)  = IFLD(3)
  58 C  -----------------------------------------------------------
  59       RETURN
  60       END