FINUFFT.jl

This is a Julia interface to FINUFFT, a lightweight and fast nonuniform FFT (nufft) library released by the Flatiron Institute. Both 64-bit and 32-bit precisions calls are supported.

Installation

The latest version of FINUFFT.jl requires Julia v1.3 or later. From the Pkg REPL mode (hit ] in REPL to enter), run

add FINUFFT

Older versions of the package are available also for Julia v1.0-v1.2, but the user need to have a recent version of GCC installed.

Usage

This module provides functions nufft1d1, nufft1d2, ..., nufft3d3, nufft1d1!, nufft1d2!, ..., nufft3d3!, nufftf1d1!, ..., nufftf3d3!, and finufft_default_opts that call the interface defined in https://finufft.readthedocs.io/en/latest/usage.html

A reference of the provided functions is available at https://ludvigak.github.io/FINUFFT.jl/latest/

• Function calls mimic the C/C++ interface, with the exception that you don't need to pass the dimensions of any arrays in the argument (they are inferred using size()).
• The functions named nufftDdN return the output array.
• The functions named nufftDdN! take the output array as an argument. This needs to be preallocated.
• The functions named nufftfDdN! are them same as above, but operate on 32-bit arguments.
• The last argument of the nufft routines is the options struct, which is optional. Default values are used if it is omitted.
• finufft_default_opts() returns an options struct with default values.
• The advanced interfaces finufft2d1many and finufft2d2many have not been implemented yet.

Example

using FINUFFT

# nonuniform data
nj = 100
x = pi*(1.0 .- 2.0*rand(nj))
c = rand(nj) + 1im*rand(nj)

# Parameters
ms = 20 # Output size
tol = 1e-10 # Tolerance

# Output as return value
fk = nufft1d1(x, c, 1, tol, ms)

# Preallocate output and pass as argument
out = Array{ComplexF64}(undef, ms)
nufft1d1!(x, c, 1, tol, out)

# Call using modified opts 
opts = finufft_default_opts()
opts.debug = 1
fk2 = nufft1d1(x, c, 1, tol, ms, opts)

More examples

See test/test_nufft.jl

TODO

• Implement advanced interface