FFTW

For version 2.0.1, 28 September 1998


(1)

Not unlike a well-known US president.

(2)

The output for the multi-dimensional rfftw is a more-conventional array of fftw_complex values, but the format here permitted us greater efficiency in one dimension.

(3)

The basic problem is the resolution of the clock: FFTW needs to run for a certain time for the clock to be reliable.

(4)

fftwnd actually may use some temporary storage (hidden in the plan), but this storage space is only the size of the largest dimension of the array, rather than being as big as the entire array. (Unless you use fftwnd to perform one-dimensional transforms, in which case the temporary storage required for in-place transforms is as big as the entire array.)

(5)

The etymologically-correct spelling would be frftw_, but it is hard to remember.

(6)

Each version of cc seems to have its own magic incantation to get the fastest code most of the time--you'd think that people would have agreed upon some convention, e.g. "-Omax", by now.


This document was generated on 22 November 1998 using the texi2html translator version 1.52. (properly hacked by athena@theory.lcs.mit.edu)