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Jun 7, 2020 at 16:09 history edited J. M.'s missing motivation
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Mar 27, 2017 at 16:39 comment added Daniel Lichtblau It might be a difference in default setting of Method option to RowReduce.
Mar 27, 2017 at 5:54 comment added Yair M Just a thought as I'm no expert. If you think the ZeroTest is the source of the difference use the ZeroTest option to use your own version of ZeroTest, and enforce the two approaches to use the same one, thus checking your hypothesis
Mar 27, 2017 at 4:19 comment added user46831 C.E. Thanks so much for the help! I'm running Mathematica 10.0 and in that version LinearSolve never did come back with an answer, even after several hours. Surprisingly, removing the last variable and equation did the trick. Without those, it solved in 8 seconds. And it's easy to compute that last variable from the answer. J.M. Thanks for the tip. I'll use it!
Mar 27, 2017 at 4:03 history edited user46831 CC BY-SA 3.0
Removing the final equation defining a variable that appears in no other equations, resolves the issue. LinearSolve knocks it off in 8 or 9 seconds
Mar 27, 2017 at 0:50 comment added J. M.'s missing motivation BTW: CoefficientArrays[] is an easier way to get the matrix and vector you need: {rhs, matrix} = Normal[CoefficientArrays[equations, variables]]; rhs = -rhs;
Mar 26, 2017 at 22:34 comment added C. E. For me, Solve takes 21 seconds and LinearSolve takes 35 seconds. So LinearSolve is slower, but not that much slower. If I run LinearSolve a second time it returns in 6.3 seconds, due to caching I suppose. Solve takes 19 seconds if I run it a second time, so it does not benefit nearly as much from caching. I'm using Mathematica 11.1.
Mar 26, 2017 at 22:15 review First posts
Mar 26, 2017 at 22:16
Mar 26, 2017 at 22:04 history asked user46831 CC BY-SA 3.0