HOPS - Handy Operations on Power Series

HOPS is a small domain specific language for working with power series and integer sequences. It comes with an interpreter and command line program called hops.

For instance, we can generate the sequence of Catalan numbers from its generating function, a functional equation, or an explicit formula for the n-th term:

$ hops --prec=11 '2/(1+sqrt(1-4*x))'
{
  "hops":"2/(1+sqrt(1-4*x))",
  "seq":[1,1,2,5,14,42,132,429,1430,4862,16796]
}

$ hops --prec=11 'C=1+x*C^2'
{
  "hops":"C=1+x*C^2",
  "seq":[1,1,2,5,14,42,132,429,1430,4862,16796]
}

$ hops --prec=11 '{(2*n)!/(n!*(n+1)!)}'
{
  "hops":"{(2*n)!/(n!*(n+1)!)}",
  "seq":[1,1,2,5,14,42,132,429,1430,4862,16796]
}

See the documentation section below for more.

Installation

Using the nix package manager:

$ nix-env -f "<nixpkgs>" -iA haskellPackages.hops

Or using cabal:

$ cabal update && cabal install hops

Documentation

• Tutorial
• Description of the HOPS language
• Man page
• Hackage

Contribute

• Issue tracker on GitHub
• Source code on GitHub
• You can also contact me directly

How to cite

@misc{hops,
  author = "Anders Claesson",
  title  = "HOPS: Handy Operations on Power Series",
  howpublished = "\url{http://akc.is/hops}"
}

License

This project is licensed under a BSD license.