Timeline for Using FindRoot on a system of equations with a singular Jacobian
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
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| Jun 7, 2021 at 7:22 | vote | accept | user112495 | ||
| Jun 5, 2021 at 18:21 | comment | added | Chris K | Can you include an example that shows the error you're trying to avoid? | |
| Jun 5, 2021 at 9:24 | answer | added | Akku14 | timeline score: 2 | |
| May 26, 2021 at 16:37 | comment | added | Roman |
Maybe obvious, but have you tried Solve[{eqn1 == 0, eqn2 == 0, x + y == 1}, {x, y}]?
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| May 26, 2021 at 15:56 | comment | added | Bob Hanlon |
"Minimize finds the global minimum of f subject to the constraints given" and "NMinimize always attempts to find a global minimum of f subject to the constraints given"; whereas, FindMinimum "searches for a local minimum". I would only use FindMinimum if neither Minimize nor NMinimize were successful.
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| May 26, 2021 at 15:53 | comment | added | Acus | It may soundsweird, however, FindInstance[{eqn1 == 0, eqn2 == 0, x + y == 1}, {x, y}, Reals] it your case works. | |
| May 26, 2021 at 15:45 | comment | added | user112495 | @BobHanlon Does Minimize work in the same way as FindMinimum? I've tried using FindMinimum, but it looks like there are quite a few very small minima in it. The solution varies quite substantially depending on starting conditions, but both with an (almost) equally low function value ($10^{-7}$) | |
| May 26, 2021 at 15:38 | comment | added | Bob Hanlon |
{min, arg} = Minimize[{eqn1^2 + eqn2^2, x + y == 1}, {x, y}]
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| May 26, 2021 at 15:29 | comment | added | user112495 | @BobHanlon Apologies. I have added an example detailing the kind of thing I would like to be able to do. | |
| May 26, 2021 at 15:29 | history | edited | user112495 | CC BY-SA 4.0 |
added 485 characters in body
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| May 26, 2021 at 14:28 | comment | added | user21 | Have a look at the Affine Covariant Newton solver and it's options. | |
| May 26, 2021 at 14:04 | comment | added | Bob Hanlon | Please provide code (InputForm) for a concrete example that demonstrates the issue. | |
| May 26, 2021 at 13:47 | history | asked | user112495 | CC BY-SA 4.0 |