In these routines, all dimensions being transformed must be even and their
largest prime factors must be no larger than 19. All transforms are done in
place and a normalization is applied in each case. The X dimension of the
array must always be dimensioned to 2 more than the dimension of the real
space image to allow space for an extra column of complex numbers. The sizes
passed to the routines are always the real-space image sizes. Thus, in
Fortran, an array would be dimensioned as:
real*4 array(nx+2, ny) or: complex array((nx+2)/2, ny)
There are no separate Fortran wrappers for these routines; their names are defined so that they can be called directly from Fortran. From C, include "cfft.h" to have the function name defined with an underscore on Unix-type systems and with capital letters on Windows. Pass all arguments by reference (as pointers).
All functions exit with an error message to standard out if the image size is not allowed or the direction parameter is incorrect.
LIST FUNCTIONS FROM odfft.c LIST FUNCTIONS FROM todfft.c LIST FUNCTIONS FROM thrdfft.c
DESCRIBE FUNCTIONS FROM odfft.c DESCRIBE FUNCTIONS FROM todfft.c DESCRIBE FUNCTIONS FROM thrdfft.c