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HyperInt

This Maple program can integrate some rational linear combinations of multiple polylogarithms. The name HyperInt reflects that it uses hyperlogarithms to achieve this. The main focus is the application to compute Feynman integrals, but it can be useful more generally. Developed by Erik Panzer.

Getting started

Download the package (this is the master branch) and extract it. Start a Maple session (version 16 or above) and enter

read "HyperInt.mpl";

HyperInt is ready to use. For example you can integrate Li[2](-x)*Li[3](-1/x)/x with

hyperInt(polylog(2,-x)*polylog(3,-1/x)/x, x=0..infinity):
fibrationBasis(%);

which gives the result 8/7*zeta[2]^3. To make sure everything is working as it should, run "HyperTests.mpl" (which is part of the package) by either loading

read "HyperTests.mpl";

in a Maple session or calling

maple HyperTests.mpl

on the command line. If any error occurs, please inform me immediately!

Further instructions can be found in the readme file (which is part of the package).

Versions

The development branch dev (download here) is more up-to-date (than master) but it can contain some experimental features which are still under development, not yet documented and not tested thoroughly.

In dev there is suggestIntegrationOrder which automatically determines a linearly reducible integration order (if such exists), given a polynomial reduction table. This is further automatized in hyperInt: Specifying the integration variables as a set (and not as a list), the order is determined automatically. For example,

hyperInt(1/((1+x)^2+y)/(y+z^2)/(1+z),{x, y, z}):
fibrationBasis(%);

triggers a reduction, then one of the linearly reducible orders [y,x,z] or [y,z,x] is found and integrated. The result should be

7/4*zeta[3]+3*ln(2)*zeta[2]

Documentation

This article describes the implementation, gives simple examples and full details on the employed algorithms:

Algorithms for the symbolic integration of hyperlogarithms with applications to Feynman integrals, Computer Physics Communications, 188:148-166, March 2015. (arXiv version)

The Maple worksheet "Manual.mw" (which is part of the package) is highly recommend to get used to HyperInt. It contains many commented examples and a special long section on Feynman integral computations.

Additional material

Periods

The HyperInt package comes with reduction tables for multiple zeta values up to weight 12 and for alternating sums up to weight 8. If you use HyperInt for computations involving higher weights, the lack of basis can result in poor runtime and huge expressions. Therefore you should use loadPeriods(filename) (after read "HyperInt.mpl") to make reduction tables to your preferred basis available for HyperInt.

The documentation explains how such files have to be set up. Below I provide alternating sums up to weigth 11 (computed from the basis in zeta_procedures by Oliver Schnetz, which in turn used the MZV datamine by Johannes Bluemlein, David Broadhurst and Jos Vermaseren):

Worksheets and scripts

I provide here several worksheets which might be useful if you want to use HyperInt.

Share and contribute

If you did any calculations with HyperInt and want to share your scripts or tips, please let me know and I will upload them here.

If you want to contribute in any way (ideas for improvements, new features, extend the wiki), please do so and contact me! This wiki uses the Markdown syntax and you can use

$ git clone https://PanzerErik@bitbucket.org/PanzerErik/hyperint.git/wiki

to clone it and edit (and add) files locally.

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