fftl — generalised FFTLog for Python

The fftl package for Python contains a routine to calculate integral transforms of the type ã(k) = ∫ a(r) T(kr) dr for arbitrary kernels T. It uses a modified FFTLog [2] method of Hamilton [1] to efficiently compute the transform on logarithmic input and output grids.

Besides the generalised FFTLog algorithm, the package also provides a number of standard integral transforms.

Installation

Install with pip:

pip install fftl

For development, it is recommended to clone the GitHub repository, and perform an editable pip installation.

The core package only requires numpy. The standard integral transform module additionally requires scipy.

Usage

The core functionality of the package is provided by the fftl module. The fftl() routine computes the generalised FFTLog integral transform for a given kernel.

For convenience, a number of standard integral transforms are implemented in the fftl.transforms module.

User manual

• Core Functionality (fftl)
• Standard Integral Transforms (fftl.transforms)

References

1. Hamilton A. J. S., 2000, MNRAS, 312, 257 (astro-ph/9905191)
2. Talman J. D., 1978, J. Comp. Phys., 29, 35