Timeline for Inactive nonlinear ODE system results in NDSolveValue::femcnmd warning
Current License: CC BY-SA 4.0
11 events
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| Jul 20, 2022 at 10:15 | history | edited | Alex Trounev | CC BY-SA 4.0 |
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| Jul 20, 2022 at 10:01 | vote | accept | Johnson | ||
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| Jul 19, 2022 at 16:15 | history | edited | Alex Trounev | CC BY-SA 4.0 |
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| Jul 19, 2022 at 10:17 | comment | added | Alex Trounev |
@xzczd Finally I got right solution with 512 collocation points. Therefore the number of points is the main factor since function Tanh[20 (-1 + L0 x)] needs to be resolved.
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| Jul 19, 2022 at 10:09 | history | edited | Alex Trounev | CC BY-SA 4.0 |
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| Jul 19, 2022 at 9:34 | comment | added | xzczd♦ | If the system owns multiple solutions, according to my (limited) experience, the initial guess should play an important role, but this problem doesn't seem to be the case… | |
| Jul 19, 2022 at 9:14 | comment | added | Alex Trounev | Yes, but in my example there is 98 points and I have tested it with 112 and 128 points as well. May be there are several branches in numerical solution? | |
| Jul 19, 2022 at 9:08 | comment | added | xzczd♦ |
Oh you're right, I forgot about the L0 generated by D… With M0 = 9 our results (almost) matches :) .
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| Jul 19, 2022 at 8:43 | comment | added | Alex Trounev |
Actually there is no mistake in mapping, since we can test my testEquations with bc, bc1 with your code and got absolutely same result as yours. But solution strictly depends on the number of collocation points. May be this is a problem?
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| Jul 19, 2022 at 7:40 | comment | added | xzczd♦ |
There seem to be simple mistakes in mapping, for example, D[(x^2 a[x] D[… should be D[((L0 x)^2 a[x] D[…. I suggest using DSolveChangeVariables or DChange to avoid possible mistakes.
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| Jul 19, 2022 at 4:48 | history | answered | Alex Trounev | CC BY-SA 4.0 |