Name

sfct_init, dfct_init − Initialization step for fast cosine transform in one dimension

FORMAT

status = {S,D}FCT_INIT (n, fct_struct, type, stride_1_flag)

Arguments

ninteger∗4
Specifies the size of the transform. n must be even and

fct_structrecord /dxml_s_fct_structure/ for single-precision operations
record /dxml_d_fct_structure/ for double-precision operations

typeinteger∗4
Specifies the type of Cosine transform desired.   Currently only type-1 and type-2 transforms are supported.

stride_1_flaglogical
Specifies the allowed distance between consecutive elements in the input and output arrays:

TRUE: Stride must be 1. 

FALSE: Stride is at least 1. 

Description

The _FCT_INIT functions build internal data structures needed to compute fast Cosine transforms of one-dimensional data.  These functions are the first step in a three-step procedure.  They create the internal data structures, using attributes defined in the file DXMLDEF.FOR. 

Use the initialization function that is appropriate for the data format. Then use the corresponding application and exit functions to complete the transform.  For example, use SFCT_INIT for the internal data structures used by SFCT_APPLY and end with the SFCT_EXIT function. 

Return Values

0DXML_SUCCESS()

4DXML_ILL_N_IS_ODD()

8DXML_ILL_N_RANGE()

12DXML_INS_RES()

17DXML_OPTION_NOT_SUPPORTED()