status = {S,D,C,Z}FFT_INIT_GRP (n, fft_struct, grp_stride_1_flag, max_grp_size)
n integer*4 Specifies the number of elements in the column within each one-dimensional data array; n > 0. For SFFT_INIT_GRP and DFFT_INIT_GRP, n must be even. fft_struct record /dxml_s_grp_fft_structure/ for single-precision real operations record /dxml_d_grp_fft_structure/ for double-precision real operations record /dxml_c_grp_fft_structure/ for single-precision complex operations record /dxml_z_grp_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. grp_stride_1_flag logical Specifies whether to allow a distance greater than 1 between elements. TRUE: Group stride must be 1. FALSE: Group stride is at least 1. max_grp_size integer*4 Specifies the expected number of sets of data. If unknown, set max_grp_size = 0.
The _FFT_INIT_GRP 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.
0 DXML_SUCCESS() 4 (real transforms only) DXML_ILL_N_IS_ODD() 8 DXML_ILL_N_RANGE() 12 DXML_INS_RES()