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Manuscript Title: FIESTA 2: parallelizeable multiloop numerical calculations
Authors: A.V. Smirnov, V.A. Smirnov, M. Tentyukov
Program title: FIESTA2
Catalogue identifier: AECP_v2_0 Distribution format: tar.gz
Journal reference: Comput. Phys. Commun. 182(2011)790
Programming language: Wolfram Mathematica 6.0 (or higher) and C.
Computer: From a desktop PC to a supercomputer.
Operating system: Unix, Linux, Windows, Mac OS X.
Has the code been vectorised or parallelized?: Yes, the code has been parallelized for use on multi-kernel computers as well as clusters via Mathlink over the TCP/IP protocol. The program can work successfully with a single processor, however, it is ready to work in a parallel environment and the use of multi-kernal processor and multi-processor computers significantly speeds up the calculation; on clusters the calculation speed can be improved even further.
RAM: Depends on the complexity of the problem
Keywords: Feynman diagrams, Sector decomposition, Numerical integration, Data-driven evaluation.
PACS: 02.60.jh, 02.70.Wz, 12.38.Bx.
Classification: 4.4, 4.12, 5, 6.5.
External routines: QLink [1], Cuba library [2], MPFR [3]
Does the new version supersede the previous version?: Yes
Nature of problem: The sector decomposition approach to evaluating Feynman integrals falls apart into the sector decomposition itself, where one has to minimize the number of sectors; the pole resolution and epsilon expansion; and the numerical integration of the resulting expression.
Solution method: The sector decomposition is based on a new strategy as well as on classical strategies such as Speer sectors. The sector decomposition, pole resolution and epsilon-expansion are performed in Wolfram Mathematica 6.0 or, preferably, 7.0 (enabling parallelization) [4]. The data is stored on hard disk via a special program, QLink [1]. The expression for integration is passed to the C-part of the code, that parses the string and performs the integration by one of the algorithms in the Cuba library package [2]. This part of the evaluation is perfectly parallelized on multi-kernel computers.
Reasons for new version: The first version of FIESTA had problems related to numerical instability, so for some classes of integrals it could not produce a result. The sector decomposition method can be applied not only for integral calculation.
Summary of revisions: New integrator library is used. New methods to deal with numerical instability (MPFR library). Parallelization in Mathematica. Parallelization on multiple computers via TCP-IP. New sector decomposition strategy (Speer sectors). Possibility of using FIESTA to for integral expansion. Possibility of using FIESTA to discover poles in d. New negative terms resolution strategies.
Restrictions: The complexity of the problem is mostly restricted by CPU time required to perform the evaluation of the integral
Running time: Depends on the complexity of the problem
References:
[1]	http://qlink08.sourceforge.net, open source;
[2]	http://www.feynarts.de/cuba/, open source;
[3]	http://www.mpfr.org/, open source;
[4]	http://www.wolfram.com/products/mathematica/index.html.