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/ IRIX Base Documentation 2001 May / SGI IRIX Base Documentation 2001 May.iso / usr / share / catman / p_man / cat3 / complib / fft1di.z / fft1di
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Text File  |  1998-10-30  |  4.2 KB  |  133 lines
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  4. ccccfffffffftttt1111ddddiiii,,,,zzzzfffffffftttt1111ddddiiii((((3333FFFF))))                                        ccccfffffffftttt1111ddddiiii,,,,zzzzfffffffftttt1111ddddiiii((((3333FFFF))))
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  8. NNNNAAAAMMMMEEEE
  9.      ccccfffffffftttt1111ddddiiii,,,, zzzzfffffffftttt1111ddddiiii ---- initialize the coefficient array for Complex-to-
  10.      Complex 1D FFT modules.
  11.  
  12. SSSSYYYYNNNNOOOOPPPPSSSSYYYYSSSS
  13.      _F_O_R_T_R_A_N _S_P_E_C_I_F_I_C_A_T_I_O_N
  14.      ssssuuuubbbbrrrroooouuuuttttiiiinnnneeee CCCCFFFFFFFFTTTT1111DDDDIIII(((( nnnn,,,, ccccooooeeeeffffffff ))))
  15.      iiiinnnntttteeeeggggeeeerrrr             nnnn
  16.      ccccoooommmmpppplllleeeexxxx             ccccooooeeeeffffffff((((nnnn++++11115555))))
  17.  
  18.      ssssuuuubbbbrrrroooouuuuttttiiiinnnneeee ZZZZFFFFFFFFTTTT1111DDDDIIII(((( nnnn,,,, ccccooooeeeeffffffff ))))
  19.      iiiinnnntttteeeeggggeeeerrrr             nnnn
  20.      ddddoooouuuubbbblllleeee ccccoooommmmpppplllleeeexxxx      ccccooooeeeeffffffff((((nnnn++++11115555))))
  21.  
  22.      _C _S_P_E_C_I_F_I_C_A_T_I_O_N
  23.      ####iiiinnnncccclllluuuuddddeeee <<<<fffffffftttt....hhhh>>>>
  24.      ccccoooommmmpppplllleeeexxxx ****ccccfffffffftttt1111ddddiiii(((( iiiinnnntttt nnnn,,,, ccccoooommmmpppplllleeeexxxx ****ccccooooeeeeffffffff))));;;;
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  26.      zzzzoooommmmpppplllleeeexxxx ****zzzzfffffffftttt1111ddddiiii(((( iiiinnnntttt nnnn,,,, zzzzoooommmmpppplllleeeexxxx ****ccccooooeeeeffffffff))));;;;
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  29. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  30.      Initialize the coefficient array which is used in the FFT modules.  This
  31.      array contains the different twiddle factors and the factorization of N
  32.      into prime numbers.
  33.      As the FFT modules cfft1d or zfft1d only read the _c_o_e_f_f array, it may be
  34.      reused as long as necessary once it has been initialized.
  35.  
  36.      In C, if _p_t_r is NULL, _c_f_f_t_1_d_i or _z_f_f_t_1_d_i returns a pointer to an
  37.      allocated buffer.
  38.  
  39.      CFFT1DI should be used to initialize the coeeficient array before any
  40.      call to CFFT1D
  41.      ZFFT1DI should be used to initialize the coeeficient array before any
  42.      call to ZFFT1D
  43.  
  44. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
  45.      NNNN ---- Integer. Specifies the length of the sequence to be transformed.
  46.      Unchanged on exit.
  47.  
  48.      CCCCOOOOEEEEFFFFFFFF ---- Array (C or Fortran) or NULL pointer(C).
  49.  
  50. EEEExxxxaaaammmmpppplllleeee ooooffff CCCCaaaalllllllliiiinnnngggg SSSSeeeeqqqquuuueeeennnncccceeee
  51.      Initializing a coefficient array for complex-to-complex FFTs of size 200.
  52.  
  53.      _F_o_r_t_r_a_n :
  54.           complex coeff(200+15)
  55.           call cfft1di( 200, coeff)
  56.  
  57.      _C :
  58.           #include <fft.h>
  59.           complex *coeff;
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. ccccfffffffftttt1111ddddiiii,,,,zzzzfffffffftttt1111ddddiiii((((3333FFFF))))                                        ccccfffffffftttt1111ddddiiii,,,,zzzzfffffffftttt1111ddddiiii((((3333FFFF))))
  71.  
  72.  
  73.  
  74.          coeff = cfft1di( 200, NULL);
  75.  
  76. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  77.           fft, cfft1d, zfft1d
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  129.                                                                         PPPPaaaaggggeeee 2222
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