| 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: rfft2b.f,v 1.5 2004/07/06 00:58:41 rodney Exp $ |
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| 11 | ! |
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| 12 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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| 13 | |
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| 14 | SUBROUTINE RFFT2B (LDIM, L, M, R, WSAVE, LENSAV, WORK, & |
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| 15 | & LENWRK, IER) |
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| 16 | INTEGER LDIM, L, M, LENSAV, LENWRK, IER |
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| 17 | REAL R(LDIM,M), WSAVE(LENSAV), WORK(LENWRK) |
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| 18 | ! |
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| 19 | ! |
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| 20 | ! Initialize IER |
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| 21 | ! |
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| 22 | IER = 0 |
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| 23 | ! |
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| 24 | ! Verify LENSAV |
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| 25 | ! |
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| 26 | LWSAV = L + INT(LOG (REAL(L))) +4 |
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| 27 | MWSAV = 2*M + INT(LOG (REAL(M))) +4 |
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| 28 | IF (LENSAV .LT. LWSAV+MWSAV) THEN |
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| 29 | IER = 2 |
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| 30 | CALL XERFFT ('RFFT2B', 6) |
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| 31 | GO TO 100 |
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| 32 | ENDIF |
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| 33 | ! |
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| 34 | ! Verify LENWRK |
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| 35 | ! |
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| 36 | IF (LENWRK .LT. 2*(L/2+1)*M) THEN |
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| 37 | IER = 3 |
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| 38 | CALL XERFFT ('RFFT2B', 8) |
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| 39 | GO TO 100 |
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| 40 | ENDIF |
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| 41 | ! |
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| 42 | ! Verify LDIM is as big as L |
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| 43 | ! |
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| 44 | IF (LDIM .LT. 2*(L/2+1)) THEN |
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| 45 | IER = 5 |
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| 46 | CALL XERFFT ('RFFT2B', -6) |
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| 47 | GO TO 100 |
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| 48 | ENDIF |
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| 49 | ! |
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| 50 | ! transform second dimension of array |
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| 51 | ! |
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| 52 | CALL CFFTMB(L/2+1,1,M,LDIM/2,R,M*LDIM/2, & |
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| 53 | & WSAVE(L+INT(LOG(REAL(L)))+5), & |
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| 54 | & 2*M+INT(LOG(REAL(M)))+4,WORK,2*(L/2+1)*M,IER1) |
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| 55 | IF(IER1.NE.0) THEN |
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| 56 | IER=20 |
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| 57 | CALL XERFFT('RFFT2B',-5) |
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| 58 | GO TO 100 |
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| 59 | ENDIF |
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| 60 | ! |
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| 61 | ! reshuffle |
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| 62 | ! |
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| 63 | DO J=1,M |
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| 64 | DO I=2,L |
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| 65 | R(I,J)=R(I+1,J) |
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| 66 | ENDDO |
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| 67 | ENDDO |
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| 68 | ! |
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| 69 | ! Transform first dimension of array |
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| 70 | ! |
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| 71 | CALL RFFTMB(M,LDIM,L,1,R,M*LDIM,WSAVE(1), & |
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| 72 | & L+INT(LOG(REAL(L)))+4,WORK,2*(L/2+1)*M,IER1) |
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| 73 | IF(IER1.NE.0) THEN |
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| 74 | IER=20 |
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| 75 | CALL XERFFT('RFFT2F',-5) |
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| 76 | GO TO 100 |
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| 77 | ENDIF |
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| 78 | ! |
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| 79 | 100 CONTINUE |
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| 80 | ! |
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| 81 | RETURN |
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| 82 | END |
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