1 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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2 | ! |
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3 | ! FFTPACK 5.0 |
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4 | ! |
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5 | ! Authors: Paul N. Swarztrauber and Richard A. Valent |
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6 | ! |
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7 | ! $Id: cfft2b.f,v 1.2 2004/06/15 21:08:32 rodney Exp $ |
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8 | ! |
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9 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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10 | |
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11 | SUBROUTINE CFFT2B (LDIM, L, M, C, WSAVE, LENSAV, & |
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12 | & WORK, LENWRK, IER) |
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13 | INTEGER L, M, LDIM, LENSAV, LENWRK, IER |
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14 | COMPLEX C(LDIM,M) |
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15 | REAL WSAVE(LENSAV), WORK(LENWRK) |
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16 | ! |
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17 | ! Initialize error return |
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18 | ! |
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19 | IER = 0 |
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20 | ! |
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21 | IF (L .GT. LDIM) THEN |
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22 | IER = 5 |
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23 | CALL XERFFT ('CFFT2B', -2) |
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24 | GO TO 100 |
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25 | ELSEIF (LENSAV .LT. 2*L + INT(LOG(REAL(L))) + & |
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26 | & 2*M + INT(LOG(REAL(M))) +8) THEN |
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27 | IER = 2 |
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28 | CALL XERFFT ('CFFT2B', 6) |
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29 | GO TO 100 |
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30 | ELSEIF (LENWRK .LT. 2*L*M) THEN |
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31 | IER = 3 |
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32 | CALL XERFFT ('CFFT2B', 8) |
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33 | GO TO 100 |
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34 | ENDIF |
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35 | ! |
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36 | ! Transform X lines of C array |
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37 | IW = 2*L+INT(LOG(REAL(L))*LOG(2.)) + 3 |
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38 | CALL CFFTMB(L, 1, M, LDIM, C, (L-1) + LDIM*(M-1) +1, & |
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39 | & WSAVE(IW), 2*M + INT(LOG(REAL(M))) + 4, & |
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40 | & WORK, 2*L*M, 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 ('CFFT2B',-5) |
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44 | GO TO 100 |
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45 | ENDIF |
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46 | ! |
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47 | ! Transform Y lines of C array |
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48 | IW = 1 |
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49 | CALL CFFTMB (M, LDIM, L, 1, C, (M-1)*LDIM + L, & |
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50 | & WSAVE(IW), 2*L + INT(LOG(REAL(L))) + 4, & |
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51 | & WORK, 2*M*L, IER1) |
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52 | IF (IER1 .NE. 0) THEN |
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53 | IER = 20 |
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54 | CALL XERFFT ('CFFT2B',-5) |
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55 | ENDIF |
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56 | ! |
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57 | 100 CONTINUE |
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58 | RETURN |
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59 | END |
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