| 1 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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| 2 | ! |
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| 3 | ! FFTPACK 5.0 |
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| 4 | ! Copyright (C) 1995-2004, Scientific Computing Division, |
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| 5 | ! University Corporation for Atmospheric Research |
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| 6 | ! Licensed under the GNU General Public License (GPL) |
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| 7 | ! |
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| 8 | ! Authors: Paul N. Swarztrauber and Richard A. Valent |
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| 9 | ! |
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| 10 | ! $Id: mcsqb1.f,v 1.2 2004/06/15 21:29:19 rodney Exp $ |
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| 11 | ! |
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| 12 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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| 13 | |
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| 14 | SUBROUTINE MCSQB1 (LOT,JUMP,N,INC,X,WSAVE,WORK,IER) |
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| 15 | DIMENSION X(INC,*) ,WSAVE(*) ,WORK(LOT,*) |
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| 16 | IER = 0 |
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| 17 | LJ = (LOT-1)*JUMP+1 |
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| 18 | NS2 = (N+1)/2 |
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| 19 | NP2 = N+2 |
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| 20 | DO 101 I=3,N,2 |
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| 21 | DO 201 M=1,LJ,JUMP |
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| 22 | XIM1 = X(M,I-1)+X(M,I) |
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| 23 | X(M,I) = .5*(X(M,I-1)-X(M,I)) |
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| 24 | X(M,I-1) = .5*XIM1 |
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| 25 | 201 CONTINUE |
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| 26 | 101 END DO |
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| 27 | DO 301 M=1,LJ,JUMP |
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| 28 | X(M,1) = .5*X(M,1) |
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| 29 | 301 END DO |
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| 30 | MODN = MOD(N,2) |
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| 31 | IF (MODN .NE. 0) GO TO 302 |
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| 32 | DO 303 M=1,LJ,JUMP |
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| 33 | X(M,N) = .5*X(M,N) |
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| 34 | 303 END DO |
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| 35 | 302 CONTINUE |
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| 36 | LENX = (LOT-1)*JUMP + INC*(N-1) + 1 |
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| 37 | LNSV = N + INT(LOG(REAL(N))) + 4 |
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| 38 | LNWK = LOT*N |
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| 39 | ! |
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| 40 | CALL RFFTMB(LOT,JUMP,N,INC,X,LENX,WSAVE(N+1),LNSV,WORK,LNWK,IER1) |
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| 41 | IF (IER1 .NE. 0) THEN |
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| 42 | IER = 20 |
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| 43 | CALL XERFFT ('MCSQB1',-5) |
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| 44 | GO TO 400 |
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| 45 | ENDIF |
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| 46 | ! |
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| 47 | DO 102 K=2,NS2 |
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| 48 | KC = NP2-K |
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| 49 | M1 = 0 |
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| 50 | DO 202 M=1,LJ,JUMP |
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| 51 | M1 = M1 + 1 |
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| 52 | WORK(M1,K) = WSAVE(K-1)*X(M,KC)+WSAVE(KC-1)*X(M,K) |
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| 53 | WORK(M1,KC) = WSAVE(K-1)*X(M,K)-WSAVE(KC-1)*X(M,KC) |
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| 54 | 202 CONTINUE |
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| 55 | 102 END DO |
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| 56 | IF (MODN .NE. 0) GO TO 305 |
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| 57 | DO 304 M=1,LJ,JUMP |
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| 58 | X(M,NS2+1) = WSAVE(NS2)*(X(M,NS2+1)+X(M,NS2+1)) |
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| 59 | 304 CONTINUE |
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| 60 | 305 DO 103 K=2,NS2 |
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| 61 | KC = NP2-K |
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| 62 | M1 = 0 |
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| 63 | DO 203 M=1,LJ,JUMP |
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| 64 | M1 = M1 + 1 |
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| 65 | X(M,K) = WORK(M1,K)+WORK(M1,KC) |
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| 66 | X(M,KC) = WORK(M1,K)-WORK(M1,KC) |
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| 67 | 203 CONTINUE |
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| 68 | 103 END DO |
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| 69 | DO 104 M=1,LJ,JUMP |
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| 70 | X(M,1) = X(M,1)+X(M,1) |
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| 71 | 104 END DO |
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| 72 | 400 CONTINUE |
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| 73 | RETURN |
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| 74 | END |
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