|Bill Allombert on Thu, 18 Jul 2013 18:59:06 +0200|
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|New GP functions qfauto/qfisom etc.|
Dear developers, I just commit a patch that add a number of PARI functions for automorphisms and isomorphisms of lattices This is a port of the program ISOM by Bernt Souvignier which implement an algorithm published in W. PLESKEN, B. SOUVIGNIER, Computing Isometries of Lattices, Journal of Symbolic Computation, Volume 24, Issues 3-4, September 1997, Pages 327-334, ISSN 0747-7171, 10.1006/jsco.1996.0130. (http://www.sciencedirect.com/science/article/pii/S0747717196901303) I like to thanks Prof. Souvignier for his permission to use his code in PARI/GP. The new functions are qfauto(L): computes the automorphisms of the lattice L given by its Gram matrice. qfisom(L1,L2): compute an isorphimsm between L1 and L2. qfisominit(L1): precompute data for faster computation of isomorphisms with L1 qfautoexport(): export the output of qfauto to GAP or MAGMA format (as a matrix group). This port is dedicated to Philippe Elbaz-Vincent. Enjoy it! Please test! Cheers, Bill.