chunkie: a MATLAB integral equation toolbox

A MATLAB package for prototyping integral equation methods in two dimensions. While chunkie is primarily intended as a proto-typing or pedagogical tool, it is designed to be reasonably efficient and has been used to produce research-grade results.

At-a-glance:

• given a parametrization of a curve, chunkie will return a "chunker" object which stores the description of the curve in chunk format (the curve is discretized into chunks such that on each chunk a legendre interpolant in parameter space is accurate to some prescribed accuracy).
• chunkie has routines for setting up system matrices corresponding to logarithmically singular integral equation kernels defined on a chunker
• chunkie is designed to inter-operate with Ken Ho's fast linear algebra in MATLAB package (FLAM)
• chunkie includes various routines for evaluating layer potentials and functions defined on chunkers

Installing chunkie

Clone the repository with the submodules

git clone --recurse-submodules https://github.com/fastalgorithms/chunkie.git

and run startup.m in the install directory. This will download the FLAM and fmm2d submodules, include FLAM in the matlab path, and generate the fmm2d mex file if a fortran compiler exists.

Using chunkie

Check out the chunkie/demo folder.

License

chunkie is copyright 2019 the chunkie team

chunkie proper (the contents of the chunkie folder) is available under the terms of the BSD 3-clause license, which should have been included in the distribution (see chunkie/LICENSE.md)

Installation notes

• The fmm2d mex installation is currently not supported on Windows, to complete the mex installation, follow instructions on the fmm2d documentation

• fmm2d mex installation depends on gfortran. In case a compiler is not found, the installation will be skipped. To install dependencies follow the procedure below based on your OS

  • MacOS

    Get xcode, command line tools by running

    xcode-select --install
    

    Then install Homebrew from https://brew.sh, and finally install gfortran using

    brew install gcc
    

  • Ubuntu linux

    sudo apt-get install make build-essential gfortran
    

  • Fedora/centOS linux

    sudo yum install make gcc gcc-c++ gcc-gfortran libgomp
    

• If installing without submodules, chunkie depends on FLAM, and optionally on the fmm2d repository. Parts of the library will not function without FLAM and its subdirectories included in the matlab path.

chunkie team

chunkie has benefitted from the contributions of several developers: Travis Askham, Manas Rachh, Michael O'Neil, Jeremy Hoskins, Dan Fortunato, Shidong Jiang, Fredrik Fryklund, Hai Yang Wang, and Hai Zhu.

James Bremer and Zydrunas Gimbutas provided generalized Gaussian quadrature rules (chunkie/+chnk/+quadggq)

Many routines were modelled after parts of the legeexps.f library (Copyright Vladimir Rokhlin, Free BSD 3-clause), FMMLIB2D (Copyright Leslie Greengard and Zydrunas Gimbutas, Free BSD 3-clause), and Johan Helsing's RCIP tutorial (https://arxiv.org/abs/1207.6737)

Contributing

Contributions are welcome. See the issues tab or create a new issue if there is something you're interested in bringing to chunkie. See the wiki for more on the developer process.