Last change
on this file was
2759,
checked in by aslmd, 2 years ago
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adding unmodified code from WRFV3.0.1.1, expurged from useless data +1M size
|
File size:
2.4 KB
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Line | |
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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: mrfti1.f,v 1.2 2004/06/15 21:29:20 rodney Exp $ |
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11 | ! |
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12 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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13 | |
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14 | SUBROUTINE MRFTI1 (N,WA,FAC) |
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15 | REAL WA(N) ,FAC(15) |
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16 | INTEGER NTRYH(4) |
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17 | DOUBLE PRECISION TPI,ARGH,ARGLD,ARG |
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18 | DATA NTRYH(1),NTRYH(2),NTRYH(3),NTRYH(4)/4,2,3,5/ |
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19 | ! |
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20 | NL = N |
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21 | NF = 0 |
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22 | J = 0 |
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23 | 101 J = J+1 |
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24 | IF (J-4) 102,102,103 |
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25 | 102 NTRY = NTRYH(J) |
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26 | GO TO 104 |
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27 | 103 NTRY = NTRY+2 |
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28 | 104 NQ = NL/NTRY |
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29 | NR = NL-NTRY*NQ |
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30 | IF (NR) 101,105,101 |
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31 | 105 NF = NF+1 |
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32 | FAC(NF+2) = NTRY |
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33 | NL = NQ |
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34 | IF (NTRY .NE. 2) GO TO 107 |
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35 | IF (NF .EQ. 1) GO TO 107 |
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36 | DO 106 I=2,NF |
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37 | IB = NF-I+2 |
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38 | FAC(IB+2) = FAC(IB+1) |
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39 | 106 END DO |
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40 | FAC(3) = 2 |
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41 | 107 IF (NL .NE. 1) GO TO 104 |
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42 | FAC(1) = N |
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43 | FAC(2) = NF |
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44 | TPI = 8.D0*DATAN(1.D0) |
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45 | ARGH = TPI/FLOAT(N) |
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46 | IS = 0 |
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47 | NFM1 = NF-1 |
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48 | L1 = 1 |
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49 | IF (NFM1 .EQ. 0) RETURN |
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50 | DO 110 K1=1,NFM1 |
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51 | IP = FAC(K1+2) |
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52 | LD = 0 |
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53 | L2 = L1*IP |
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54 | IDO = N/L2 |
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55 | IPM = IP-1 |
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56 | DO 109 J=1,IPM |
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57 | LD = LD+L1 |
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58 | I = IS |
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59 | ARGLD = FLOAT(LD)*ARGH |
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60 | FI = 0. |
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61 | DO 108 II=3,IDO,2 |
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62 | I = I+2 |
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63 | FI = FI+1. |
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64 | ARG = FI*ARGLD |
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65 | WA(I-1) = DCOS(ARG) |
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66 | WA(I) = DSIN(ARG) |
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67 | 108 CONTINUE |
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68 | IS = IS+IDO |
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69 | 109 CONTINUE |
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70 | L1 = L2 |
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71 | 110 END DO |
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72 | RETURN |
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73 | END |
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