Nfft3 is a software library written in c for computing nonequispaced fast fourier and related transformations. in detail, nfft3 implements:

1) the nonequispaced fast fourier transform (nfft)
- the forward transform (nfft)
- the adjoint transform (adjoint nfft)
2) generalisations of the nfft
- to arbitrary knots in time and frequency domain (nnfft)
- to the sphere s^2 (nfsft)
- to the hyperbolic cross (nsfft)
- to real-valued data, i.e. (co)sine transforms, (nfct, nfst)
- to the rotation group (nfsoft)
3) generalised inverses based on iterative methods, e.g. cgnr, cgne 4) applications in
- medical imaging
(i) magnetic resonance imaging
(ii) computerised tomography
- summation schemes
(i) fast gauss transform (fgt)
(ii) singular kernels
(iii) zonal kernels
- polar fft, discrete radon transform, ridgelet transform
this package provides the shared library compiled with double precision.