Ninja: Automated integrand reduction via Laurent expansion for one-loop amplitudes

We present the public C++ library Ninja, which implements the Integrand Reduction via Laurent Expansion method for the computation of one-loop integrals. The algorithm is suited for applications to complex one-loop processes.Program summaryProgram title: NinjaCatalogue identifier: AETO_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AETO_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: GNU General Public License, version 3No. of lines in distributed program, including test data, etc.: 74303No. of bytes in distributed program, including test data, etc.: 530944Distribution format: tar.gzProgramming language: C++.Computer: Any computer with a compliant C++ compiler.Operating system: Unix-like (tested on Linux and Mac OS).RAM: Several thousands of bytes (it can vary depending on the complexity of the computation)Classification: 4.4, 11.1.External routines: A library of one-loop Master Integrals:OneLOop, LoopTools, or any other library implementing a suitable interfaceNature of problem:Computation of one-loop integrals contributing to scattering amplitudes.Solution method:Semi-numerical implementation of the integrand reduction via Laurent expansion, using a simplified polynomial division algorithm.Running time:Depending on the number of integrals and their complexity, between less than a millisecond up to several seconds per phase-space point, for the computation of a full amplitude.