1 | ! |
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2 | ! $Id: mod_fft_fftw.F90 1389 2010-05-18 07:48:01Z oboucher $ |
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3 | ! |
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4 | |
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5 | MODULE mod_fft_fftw |
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6 | |
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7 | #ifdef FFT_FFTW |
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8 | |
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9 | REAL, SAVE :: scale_factor |
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10 | INTEGER, SAVE :: vsize |
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11 | INTEGER, PARAMETER :: inc=1 |
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12 | |
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13 | INTEGER*8, ALLOCATABLE, DIMENSION(:), SAVE :: plan_forward |
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14 | INTEGER*8, ALLOCATABLE, DIMENSION(:), SAVE :: plan_backward |
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15 | |
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16 | CONTAINS |
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17 | |
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18 | SUBROUTINE Init_fft(iim,nvectmax) |
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19 | IMPLICIT NONE |
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20 | #include <fftw3.f> |
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21 | INTEGER :: iim |
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22 | INTEGER :: nvectmax |
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23 | |
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24 | INTEGER :: itmp |
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25 | |
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26 | INTEGER :: rank |
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27 | INTEGER :: howmany |
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28 | INTEGER :: istride, idist |
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29 | INTEGER :: ostride, odist |
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30 | INTEGER, DIMENSION(1) :: n_array, inembed, onembed |
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31 | |
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32 | REAL, DIMENSION(iim+1,nvectmax) :: dbidon |
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33 | COMPLEX, DIMENSION(iim/2+1,nvectmax) :: cbidon |
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34 | |
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35 | vsize = iim |
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36 | scale_factor = 1./SQRT(1.*vsize) |
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37 | |
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38 | dbidon = 0 |
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39 | cbidon = 0 |
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40 | |
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41 | ALLOCATE(plan_forward(nvectmax)) |
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42 | ALLOCATE(plan_backward(nvectmax)) |
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43 | |
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44 | WRITE(*,*)"!---------------------!" |
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45 | WRITE(*,*)"! !" |
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46 | WRITE(*,*)"! INITIALISATION FFTW !" |
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47 | WRITE(*,*)"! !" |
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48 | WRITE(*,*)"!---------------------!" |
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49 | |
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50 | ! On initialise tous les plans |
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51 | DO itmp = 1, nvectmax |
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52 | rank = 1 |
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53 | n_array(1) = iim |
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54 | howmany = itmp |
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55 | inembed(1) = iim + 1 ; onembed(1) = iim/2 + 1 |
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56 | istride = 1 ; ostride = 1 |
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57 | idist = iim + 1 ; odist = iim/2 + 1 |
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58 | |
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59 | CALL dfftw_plan_many_dft_r2c(plan_forward(itmp), rank, n_array, howmany, & |
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60 | & dbidon, inembed, istride, idist, & |
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61 | & cbidon, onembed, ostride, odist, & |
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62 | & FFTW_ESTIMATE) |
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63 | |
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64 | rank = 1 |
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65 | n_array(1) = iim |
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66 | howmany = itmp |
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67 | inembed(1) = iim/2 + 1 ; onembed(1) = iim + 1 |
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68 | istride = 1 ; ostride = 1 |
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69 | idist = iim/2 + 1 ; odist = iim + 1 |
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70 | CALL dfftw_plan_many_dft_c2r(plan_backward(itmp), rank, n_array, howmany, & |
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71 | & cbidon, inembed, istride, idist, & |
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72 | & dbidon, onembed, ostride, odist, & |
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73 | & FFTW_ESTIMATE) |
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74 | |
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75 | ENDDO |
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76 | |
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77 | WRITE(*,*)"!-------------------------!" |
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78 | WRITE(*,*)"! !" |
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79 | WRITE(*,*)"! FIN INITIALISATION FFTW !" |
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80 | WRITE(*,*)"! !" |
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81 | WRITE(*,*)"!-------------------------!" |
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82 | |
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83 | END SUBROUTINE Init_fft |
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84 | |
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85 | |
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86 | SUBROUTINE fft_forward(vect,TF_vect,nb_vect) |
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87 | IMPLICIT NONE |
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88 | #include <fftw3.f> |
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89 | INTEGER,INTENT(IN) :: nb_vect |
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90 | REAL,INTENT(IN) :: vect(vsize+inc,nb_vect) |
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91 | COMPLEX,INTENT(OUT) :: TF_vect(vsize/2+1,nb_vect) |
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92 | |
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93 | CALL dfftw_execute_dft_r2c(plan_forward(nb_vect),vect,TF_vect) |
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94 | |
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95 | TF_vect = scale_factor * TF_vect |
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96 | |
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97 | END SUBROUTINE fft_forward |
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98 | |
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99 | SUBROUTINE fft_backward(TF_vect,vect,nb_vect) |
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100 | IMPLICIT NONE |
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101 | #include <fftw3.f> |
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102 | INTEGER,INTENT(IN) :: nb_vect |
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103 | REAL,INTENT(OUT) :: vect(vsize+inc,nb_vect) |
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104 | COMPLEX,INTENT(IN ) :: TF_vect(vsize/2+1,nb_vect) |
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105 | |
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106 | CALL dfftw_execute_dft_c2r(plan_backward(nb_vect),TF_vect,vect) |
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107 | |
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108 | vect = scale_factor * vect |
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109 | |
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110 | END SUBROUTINE fft_backward |
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111 | |
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112 | #endif |
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113 | |
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114 | END MODULE mod_fft_fftw |
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