nfft_solver_1d: Inverse of the 1-D NFFT.

In gzt/rNFFT: Fast Fourier Transform at Nonequispaced Nodes

Description

1-D NFFT solver

Usage

nfft_solver_1d(x, f, n, eps = 1e-12, iterations = 10)

Arguments

x	input vector (real, length m)
f	Outputted Fourier coefficients (complex, length m)
n	Number of coefficients for the inverse - must be even.
eps	convergence criterion
iterations	number of iterations for solve to run (at most)

Details

Unlike in the case of the equispaced Fourier transform, the adjoint is NOT the inverse of the non-equispaced Fourier transform. The solution must be found numerically.

Value

vector of length n of solutions f_hat.

Author(s)

Geoffrey Z. Thompson

Examples

set.seed(20190722)
x = runif(8) - 0.5
f = 1:8
for(i in 1:8) f[i] = runif(1)*1i + runif(1)
x
f
nfft_solver_1d(x,f,16,1e-35,8)
nfft_1d(x, nfft_solver_1d(x,f,16,eps = 1e-35))

gzt/rNFFT documentation built on April 15, 2020, 6:07 p.m.