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: mrftb1.f,v 1.2 2004/06/15 21:29:20 rodney Exp $ |
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8 | ! |
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9 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
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10 | |
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11 | SUBROUTINE MRFTB1 (M,IM,N,IN,C,CH,WA,FAC) |
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12 | REAL CH(M,*), C(IN,*), WA(N) ,FAC(15) |
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13 | ! |
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14 | NF = FAC(2) |
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15 | NA = 0 |
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16 | DO 10 K1=1,NF |
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17 | IP = FAC(K1+2) |
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18 | NA = 1-NA |
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19 | IF(IP .LE. 5) GO TO 10 |
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20 | IF(K1 .EQ. NF) GO TO 10 |
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21 | NA = 1-NA |
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22 | 10 END DO |
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23 | HALF = .5 |
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24 | HALFM = -.5 |
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25 | MODN = MOD(N,2) |
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26 | NL = N-2 |
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27 | IF(MODN .NE. 0) NL = N-1 |
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28 | IF (NA .EQ. 0) GO TO 120 |
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29 | M2 = 1-IM |
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30 | DO 117 I=1,M |
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31 | M2 = M2+IM |
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32 | CH(I,1) = C(M2,1) |
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33 | CH(I,N) = C(M2,N) |
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34 | 117 END DO |
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35 | DO 118 J=2,NL,2 |
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36 | M2 = 1-IM |
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37 | DO 118 I=1,M |
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38 | M2 = M2+IM |
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39 | CH(I,J) = HALF*C(M2,J) |
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40 | CH(I,J+1) = HALFM*C(M2,J+1) |
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41 | 118 CONTINUE |
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42 | GO TO 124 |
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43 | 120 continue |
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44 | DO 122 J=2,NL,2 |
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45 | M2 = 1-IM |
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46 | DO 122 I=1,M |
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47 | M2 = M2+IM |
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48 | C(M2,J) = HALF*C(M2,J) |
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49 | C(M2,J+1) = HALFM*C(M2,J+1) |
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50 | 122 CONTINUE |
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51 | 124 L1 = 1 |
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52 | IW = 1 |
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53 | DO 116 K1=1,NF |
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54 | IP = FAC(K1+2) |
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55 | L2 = IP*L1 |
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56 | IDO = N/L2 |
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57 | IDL1 = IDO*L1 |
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58 | IF (IP .NE. 4) GO TO 103 |
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59 | IX2 = IW+IDO |
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60 | IX3 = IX2+IDO |
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61 | IF (NA .NE. 0) GO TO 101 |
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62 | CALL MRADB4 (M,IDO,L1,C,IM,IN,CH,1,M,WA(IW),WA(IX2),WA(IX3)) |
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63 | GO TO 102 |
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64 | 101 CALL MRADB4 (M,IDO,L1,CH,1,M,C,IM,IN,WA(IW),WA(IX2),WA(IX3)) |
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65 | 102 NA = 1-NA |
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66 | GO TO 115 |
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67 | 103 IF (IP .NE. 2) GO TO 106 |
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68 | IF (NA .NE. 0) GO TO 104 |
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69 | CALL MRADB2 (M,IDO,L1,C,IM,IN,CH,1,M,WA(IW)) |
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70 | GO TO 105 |
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71 | 104 CALL MRADB2 (M,IDO,L1,CH,1,M,C,IM,IN,WA(IW)) |
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72 | 105 NA = 1-NA |
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73 | GO TO 115 |
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74 | 106 IF (IP .NE. 3) GO TO 109 |
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75 | IX2 = IW+IDO |
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76 | IF (NA .NE. 0) GO TO 107 |
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77 | CALL MRADB3 (M,IDO,L1,C,IM,IN,CH,1,M,WA(IW),WA(IX2)) |
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78 | GO TO 108 |
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79 | 107 CALL MRADB3 (M,IDO,L1,CH,1,M,C,IM,IN,WA(IW),WA(IX2)) |
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80 | 108 NA = 1-NA |
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81 | GO TO 115 |
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82 | 109 IF (IP .NE. 5) GO TO 112 |
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83 | IX2 = IW+IDO |
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84 | IX3 = IX2+IDO |
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85 | IX4 = IX3+IDO |
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86 | IF (NA .NE. 0) GO TO 110 |
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87 | CALL MRADB5 (M,IDO,L1,C,IM,IN,CH,1,M,WA(IW),WA(IX2), & |
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88 | & WA(IX3),WA(IX4)) |
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89 | GO TO 111 |
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90 | 110 CALL MRADB5 (M,IDO,L1,CH,1,M,C,IM,IN,WA(IW),WA(IX2), & |
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91 | & WA(IX3),WA(IX4)) |
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92 | 111 NA = 1-NA |
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93 | GO TO 115 |
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94 | 112 IF (NA .NE. 0) GO TO 113 |
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95 | CALL MRADBG (M,IDO,IP,L1,IDL1,C,C,C,IM,IN,CH,CH,1, & |
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96 | & M,WA(IW)) |
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97 | GO TO 114 |
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98 | 113 CALL MRADBG (M,IDO,IP,L1,IDL1,CH,CH,CH,1,M,C,C,IM, & |
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99 | & IN,WA(IW)) |
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100 | 114 IF (IDO .EQ. 1) NA = 1-NA |
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101 | 115 L1 = L2 |
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102 | IW = IW+(IP-1)*IDO |
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103 | 116 END DO |
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104 | RETURN |
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105 | END |
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