Install libnfft3-long2 by entering the following commands in the terminal:
sudo apt update sudo apt install libnfft3-long2
library for computing non-uniform Fourier transforms (long-double precision)
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 long-double precision.