Timeline for Can I use WolframScript to solve this system of equations?
Current License: CC BY-SA 4.0
14 events
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| Jun 1, 2023 at 17:45 | comment | added | evanb | Do you have reason to expect a symbolic expression for the global minimum exists? | |
| Jun 1, 2023 at 17:10 | comment | added | Lawton |
@UlrichNeumann I'd like to get symbolic expressions for x, y, and z in terms of a, b, c, d, and dMax as variables, rather than getting specific numeric values for x, y, and z for specific numeric values of a, b, c, d, and dMax.
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| Jun 1, 2023 at 17:08 | comment | added | Lawton | @evanb You're right, I had forgotten to remove that underscore. After fixing that I no longer get an error, but I left the program running for 12 hours and it didn't return any result. | |
| May 31, 2023 at 7:40 | history | edited | Ulrich Neumann | CC BY-SA 4.0 |
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| May 30, 2023 at 17:52 | comment | added | evanb |
At the end there it looks like you have dMax_ (with an underscore). Try removing that (not from the left-hand side of mini[... dMax_] = , it's needed there; but from the right-hand-side of that statement).
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| May 30, 2023 at 14:55 | comment | added | Lawton |
Using your new suggestion, I get the error NMinimize::bcons: The following constraints are not valid: {a b (a + b - 4 x - 2 y - z) + x (x + y) (2 x + y + z) == 0, (-(x (x + y) (2 x + y + z) (y^2 + 5 x (x + y) + 2 x z + y z)) + a b ((a + b) (a + b - 4 x - 2 y - z)^2 - 12 c d (a + b - c - d - 4 x - 2 y - z) + x (x + y) (2 x + y + z)))/12 == (dMax_)}. Constraints should be equalities, inequalities, or domain specifications involving the variables.
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| May 30, 2023 at 14:43 | comment | added | Lawton | I did not change the content of my question with regards to what variables I wanted to solve for. You can look at the edit history yourself to confirm that. | |
| May 30, 2023 at 8:02 | history | edited | Ulrich Neumann | CC BY-SA 4.0 |
added 208 characters in body
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| May 30, 2023 at 7:48 | comment | added | Ulrich Neumann | @Lawton You changed the question without notification. Now you're looking for optimal x,y,z!!! | |
| May 29, 2023 at 22:35 | comment | added | Lawton |
I think I didn't convey everything to you fully. D and d were separate variables. I've updated my question to not use single-uppercase-character variable names per Michael E2, so now the function g should now be equal to dMax. I also want to solve for x, y, and z in terms of the other named variables; setting x, y, and z to a specific value seems counterproductive. I'm now trying Minimize[{h, {f == 0, g == dMax, a > 0, b > 0, c > 0, d > 0}}, {x, y, z}]; I'll update with how it goes.
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| May 29, 2023 at 20:29 | comment | added | Ulrich Neumann |
Block[{x = 1, y = 1, z = 1}, NMinimize[{h, {f == 0, g == d, a > 0, b > 0, c > 0, d > 0}}, {a, b, c, d}] ] evaluates in .5 seconds!
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| May 29, 2023 at 18:22 | comment | added | Lawton |
I tried NMinimize[{h, {f == 0, g == d, A > 0, B > 0, C > 0, D > 0}}, {A, B, C, D}] and the program ran for about half an hour at around 40% CPU usage and using steadily increasing amounts of RAM until it reached 63.8 out of 64 GB, then another ten minutes or so at 100% hard-disk utilization, before crashing with an error that there was no more memory available. I then tried Minimize[{h, {f == 0, g == d, A > 0, B > 0, C > 0, D > 0}}, {A, B, C, D}], and it's been running at between 70% and 90% CPU utilization for five hours with no sign of progress. Is this expected or is something wrong?
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| May 28, 2023 at 15:36 | review | Low quality posts | |||
| May 28, 2023 at 16:15 | |||||
| May 28, 2023 at 15:20 | history | answered | Ulrich Neumann | CC BY-SA 4.0 |