Numo::Pocketfft

Numo::Pocketfft provides functions for performing descrete Fourier Transform with Numo::NArray by using pocketfft as backgroud library.

Note: There are other useful Ruby gems perform descrete Fourier Transform with Numo::NArray: Numo::FFTW and Numo::FFTE by Masahiro Tanaka.

Numo::Pocketfft bundles pocketfft codes, so there is no need to install another external library in advance. Add this line to your application's Gemfile:

gem 'numo-pocketfft'

And then execute:

$ bundle

Or install it yourself as:

$ gem install numo-pocketfft

require 'numo/narray'
require 'numo/pocketfft'

a = Numo::DFloat[1, 1, 1, 1]
# => Numo::DFloat#shape=[4]
# [1, 1, 1, 1]

b = Numo::Pocketfft.rfft(a)
# => Numo::DComplex#shape=[3]
# [4+0i, 0+0i, 0+0i]

Numo::Pocketfft.irfft(b)
# => Numo::DFloat#shape=[4]
# [1, 1, 1, 1]

c = Numo::DFloat.new(2, 2).rand + Complex::I * Numo::DFloat.new(2, 2).rand
# => Numo::DComplex#shape=[2,2]
# [[0.0617545+0.116041i, 0.373067+0.344032i],
#  [0.794815+0.539948i, 0.201042+0.737815i]]

Numo::Pocketfft.ifft2(Numo::Pocketfft.fft2(c))
#=> Numo::DComplex#shape=[2,2]
#[[0.0617545+0.116041i, 0.373067+0.344032i],
# [0.794815+0.539948i, 0.201042+0.737815i]]

Bug reports and pull requests are welcome on GitHub at https://github.com/yoshoku/numo-pocketfft. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the BSD-3-Clause License.