CTITLEARCON  -- CONVOLUTION                                             00010001
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
CA    AUTHOR            L. B. LIN                                       00020000
CA    DESIGNER          L. B. LIN                                       00030000
CA    LANGUAGE          FORTRAN                                         00040000
CA    SYSTEM            IBM (SEE CRAY)                                  00050001
CA    WRITTEN           10/21/85                                        00060000
C     REVISED           05-30-86 ESN. MAKE FUNCTIONAL BY INVOKING       00070000
C                                CALL TO CRAY ROUTINE FILTGS.           00080000
C     REVISED           06-05-86 ESN. FOR USE ON THE IBM.               00090001
CA                                                                      00100000
CA                                                                      00110000
CA    CALL ARCON (F, NF, A, B, N, NRM)                                  00120001
CA          INPUT   F = REAL FILTER ARRAY                           R4  00130000
CA          INPUT  NF = NUMBER OF ELEMENTS IN F                     I4  00140000
CA          INPUT   A = REAL DATA ARRAY                             R4  00150000
CA          OUTPUT  B = REAL DATA ARRAY                             R4  00160000
CA          INPUT   N = NUMBER OF ELEMENTS IN B (OUTPUT POINTS)     I4  00170000
CA          INPUT NRM = NORMALIZATION KEY, IF NON-ZERO THE OUTPUT   I4  00180000
CA                      WILL BE DIVIDED BY THE NUMBER OF FILTER         00190000
CA                      POINTS                                          00200000
CA                                                                      00210000
CA                                                                      00220000
CA       ARCON PERFORMS CONVOLUTION ON THE INPUT REAL DATA ARRAY A WITH 00230001
CA       THE REAL FILTER ARRAY F.  THE N OUTPUT POINTS ARE STORED IN THE00240001
CA       REAL ARRAY B.  NORMALIZATION BY THE NUMBER OF FILTER POINTS IS 00250001
CA       PERFORMED ON THE OUTPUT IF NRM IS NON-ZERO.                    00260001
CAEND                                                                   00270000
      SUBROUTINE ARCON (F, NF, A, B, N, NRM)                            00280000
C                                                                       00290000
      REAL    A      (1)                                                00300000
      REAL    B      (N)                                                00310000
      REAL    F      (NF)                                               00320000
C                                                                       00330000
          DO 20 I = 1, N                                                00340000
          B(I) = 0.0                                                    00350000
C                                                                       00360000
             DO 10 J = 1, NF                                            00370000
   10        B(I) = B(I) + F(J) * A(I+J-1)                              00380000
C                                                                       00390000
   20     CONTINUE                                                      00400000
C                                                                       00410000
      IF (NRM .NE. 0) THEN                                              00420000
          CONS = NF                                                     00430000
          CALL ARDVFC (B, B, CONS, N)                                   00440000
      ENDIF                                                             00450000
C                                                                       00460000
      RETURN                                                            00470000
C                                                                       00480000
      END                                                               00490000