Testing for invertible matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg39676] Testing for invertible matrix*From*: Bob Harris <NspamITmeLION at MINDnotSPRING.COM>*Date*: Sat, 1 Mar 2003 02:48:33 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Howdy, If there some means to test whether a square matrix is invertible, rather than trying Invert[] and having it fail? I'm working on a notebook that's searching through randomly generated matrices, looking for one for which the inverse has certain properties. Thus inside my search function I have a loop something like this: While [... some condition , t = ... create a matrix ; q = Inverse[t] ; ... perform some computation using the entries in q to determine if the exit condition will be met ]; But if t is singular, computing the inverse fails. Nevertheless my loop keeps running for a while, but generates a few more annoying messages (because access to q fails) before it finally quits. What I would rather do is something like this: While [... some condition , t = ... create a matrix ; If [ t is singular, Continue[]]; q = ... inverse of matrix ; ... perform some computation using the entries in q to determine if the exit condition will be met ]; But looking through the mathematica book, I haven't come across a way to do that. I also considered that Inverse[] would have some means for me to tell it how to handle the failure condition, but I don't see anything in the book about that. Thanks in advance for any help, Bob H Lawrenceville, GA

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