Parallelising a set of 2-D frequency transforms in a flexible manner

The implementation of parallel two-dimensional frequency transforms intended for the acceleration of image-processing algorithms is described. The way these routines fit into a wider generic format for such parallel routines is also indicated. There is a brief consideration of the design decisions needed to combine the choice of efficient routine with wide utility. Due consideration is given to auxiliary functions. Details are included of the book-keeping required to enable real-valued data to be efficiently transformed in a parallel setting