sporadic failure of SingularValueDecomposition[] in Mathematica 5.2

*To*: mathgroup at smc.vnet.net*Subject*: [mg60563] sporadic failure of SingularValueDecomposition[] in Mathematica 5.2*From*: John Sidles <sidles at u.washington.edu>*Date*: Tue, 20 Sep 2005 05:19:38 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Dear Mathgroup folks Has anyone else encountered sporadic failure of SingularValueDecomposition[]? Running Mathematica 5.2 under OS X, our UW Quantum System Engineering (QSE) group is finding that SVD fails completely, for well-conditioned Hermitian input matrices, about one time in 1000. A test matrix for which SingularValueDecomposition[] fails completely can be found in this directory: http://faculty.washington.edu/sidles/mma_svd_failure_example/ The directory contains the following files: mma_svd_matrix.m (* a 90x90 Hermitian matrix for which SVD fails *) mma_svd_failure_example.pdf (* notebook demonstrating the failure *) mma_svd_failure_example.pdf (* PDF of above *) It would be a big help if someone running Unix or Windows would report on whether this matrix fails for them. Thanks in advance !!! John Sidles

**Follow-Ups**:**Re: sporadic failure of SingularValueDecomposition[] in Mathematica 5.2***From:*Pratik Desai <pdesai1@umbc.edu>