ftu

several routines for use with fourier transforms

Contents

As of now the library contains the routines:

• expandR2C, which expands the output vector of a R->C transform
  to the whole field size and
• shift and ishift, which produces the known "shifted" fields,
  used after and before a fft or ifft respectively.

All of these routines are available in 1d, which entails the suffix _1d
and also in three different precisions (float, double, long double) as well
as complex numbers. The latter combined with the library prefix ftu
results for example in the prefixes

• ftuf_ for the real float library,
• ftuc_ for the complex double library and
• ftulc_ for the complex long double library.