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: cosqmb.f,v 1.2 2004/06/15 21:14:57 rodney Exp $ |
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8 | ! |
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9 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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10 | |
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11 | SUBROUTINE COSQMB (LOT, JUMP, N, INC, X, LENX, WSAVE, LENSAV, & |
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12 | & WORK, LENWRK, IER) |
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13 | INTEGER LOT, JUMP, N, INC, LENX, LENSAV, LENWRK, IER |
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14 | REAL X(INC,*), WSAVE(LENSAV), WORK(LENWRK) |
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15 | LOGICAL XERCON |
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16 | ! |
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17 | IER = 0 |
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18 | ! |
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19 | IF (LENX .LT. (LOT-1)*JUMP + INC*(N-1) + 1) THEN |
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20 | IER = 1 |
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21 | CALL XERFFT ('COSQMB', 6) |
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22 | GO TO 300 |
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23 | ELSEIF (LENSAV .LT. 2*N + INT(LOG(REAL(N))) +4) THEN |
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24 | IER = 2 |
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25 | CALL XERFFT ('COSQMB', 8) |
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26 | GO TO 300 |
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27 | ELSEIF (LENWRK .LT. LOT*N) THEN |
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28 | IER = 3 |
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29 | CALL XERFFT ('COSQMB', 10) |
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30 | GO TO 300 |
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31 | ELSEIF (.NOT. XERCON(INC,JUMP,N,LOT)) THEN |
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32 | IER = 4 |
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33 | CALL XERFFT ('COSQMB', -1) |
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34 | GO TO 300 |
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35 | ENDIF |
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36 | ! |
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37 | LJ = (LOT-1)*JUMP+1 |
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38 | IF (N-2) 101,102,103 |
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39 | 101 DO 201 M=1,LJ,JUMP |
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40 | X(M,1) = X(M,1) |
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41 | 201 END DO |
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42 | RETURN |
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43 | 102 SSQRT2 = 1./SQRT(2.) |
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44 | DO 202 M=1,LJ,JUMP |
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45 | X1 = X(M,1)+X(M,2) |
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46 | X(M,2) = SSQRT2*(X(M,1)-X(M,2)) |
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47 | X(M,1) = X1 |
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48 | 202 END DO |
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49 | RETURN |
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50 | 103 CALL MCSQB1 (LOT,JUMP,N,INC,X,WSAVE,WORK,IER1) |
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51 | IF (IER1 .NE. 0) THEN |
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52 | IER = 20 |
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53 | CALL XERFFT ('COSQMB',-5) |
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54 | ENDIF |
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55 | ! |
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56 | 300 CONTINUE |
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57 | RETURN |
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58 | END |
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