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symb, num, none - quite a difference!
Rank: Administration Groups: Registered, Advanced Member Joined: 23/06/2009(UTC) Posts: 1,740 Was thanked: 318 time(s) in 268 post(s)
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Hello, Here is a part of the file and the expression on the left is Optimization|Symbolic Quite different numbers than the Numeric and None Here is the entire file Primer29.smThis time the same is on both WinXP and Ubuntu. If nobody can reproduce this one as well () - something must be quite wrong with my computer. Regards, Radovan |
When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!" |
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Rank: Administration Groups: Developers, Registered, Knovel Developers, Administrators, Advanced Member Joined: 11/07/2008(UTC) Posts: 1,616 Was thanked: 1978 time(s) in 666 post(s)
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Reproduced. Will check it later today. Thank you.
Best regards.
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1 user thanked Andrey Ivashov for this useful post.
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Rank: Administration Groups: Registered, Advanced Member Joined: 23/06/2009(UTC) Posts: 1,740 Was thanked: 318 time(s) in 268 post(s)
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Thank you Andrey, Here is another part from one of my working files. Difference again between Symbolic and Numeric optimization of the equations. Symbolic: The accompanied file sym.smNumeric: The accompanied file num.smPlease look at the yellow regions. I am not quite sure which one is correct, but solving in another software gave the same solution when the SMath numerical optimization was used. Moreover, further calculation showed that the numerical result should be accepted and the symbolic is questionable. To be honest, I am a bit frustrated that roots() failed here as well. If it works for you - than must be my computer again. There were another situations when roots() failed in another of my working files. I will post them as soon as I get them ready to report the problem. Here is a file where roots() failed for me in every calculation (either I made a mistake I didn't see or something else) Primer29-roots%20failed.sm. Fortunately, Newton-Raphson worked here and I managed to solve this somehow. Playing with Optimization will make a mess - Jacobian elements equal to all zeros, different results etc. I desperately need a rock solid numerical solvers for nonlinear system of equations built in SMath but, unfortunately, roots() disappointed me at the moment. Regards, Radovan Edited by user 12 February 2012 21:35:04(UTC)
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When Sisyphus climbed to the top of a hill, they said: "Wrong boulder!" |
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Rank: Member Groups: Registered
Joined: 19/01/2012(UTC) Posts: 12 Was thanked: 3 time(s) in 2 post(s)
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Hello, I found also a problem when calculating with numeric optimization. The following simple calculation adds up some integer numbers with floating point numbers. The result should always be zero. The first numeric solution does not equal zero. When I introduce some brackets around the floating point numbers, the result is correct. When using symbolic optimization the result is always correct. Left: Numeric, Right: Symbolic File: optimization.sm
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