status = {S,D,C,Z}FFT_INIT (n, fft_struct, stride_1_flag)
n integer*4 Specifies the number of values to be transformed, that is, the length of the array to be transformed; n > 0. For real operations, n must be even. fft_struct record /dxml_s_fft_structure/ for single-precision real operations record /dxml_d_fft_structure/ for double-precision real operations record /dxml_c_fft_structure/ for single-precision complex operations record /dxml_z_fft_structure/ for double-precision complex operations You must include this argument but it needs no additional definitions. The argument is declared in the program before this routine. See the CXML Reference Guide for more information. stride_1_flag logical Specifies the allowed distance between consecutive elements in the input and output arrays: TRUE: Stride must be 1. FALSE: Stride is at least 1.
The _FFT_INIT functions build internal data structures needed to compute fast Fourier transforms of one-dimensional data. These routines are the first step in a three-step procedure. They create the internal data structures, using attributes defined in the file CXMLDEF.FOR. Use the initialization routine that is appropriate for the data format. Then use the corresponding application and exit routines to complete the transform. For example, use SFFT_INIT for the internal data structures used by SFFT_APPLY and end with the SFFT_EXIT routine.
0 DXML_SUCCESS() 4(real transforms only) DXML_ILL_N_IS_ODD() 8 DXML_ILL_N_RANGE() 12 DXML_INS_RES()