New answers tagged

1 vote

Is a four-variable function less than one?

The command FindInstance[{f >= 1, x >= 0, w >= 1, y > 0, z > 0}, {w, x, y, z}] returns {} which, if one trusts ...
AccidentalFourierTransform's user avatar
0 votes

Chi-square minimization error

The problem is caused by "NDSolve". It should localize the dummy variable "t", but fails to do so. Consider: ...
Daniel Huber's user avatar
  • 47.3k
2 votes

Chi-square minimization error

Three comments: solve for all variables simultaneously instead of solving for $(x,y,z)$ first and $w$ second, use NonlinearModelFit instead of writing your own ...
Roman's user avatar
  • 46.2k
4 votes
Accepted

Optimizing an ODE fitting algorithm with interpolated data

Another way to do the fitting. 1 - We will using a custom-made second order interpolation as giving in f[t]. A dummy extra data point was introduced to facilitate ...
Cesareo's user avatar
  • 3,828
3 votes

Optimizing an ODE fitting algorithm with interpolated data

This problem has 4 parameters, and only 6 x 3 = 18 data points. I suspect that this problem is only weakly determined, if you consider the "Rule of 10" which states that you should have 10 ...
Eric Brown's user avatar
  • 4,406
2 votes
Accepted

'The objective function is not a scalar' in NMinimize

You define beta in NMinimize as a scalar. Replacing beta by: 1 and evaluating: ...
Daniel Huber's user avatar
  • 47.3k
1 vote

Why hasn't the minimum value of a+b been determined?

As the first condition is actually an equation, we may solve for b: sol=Solve[9 == 9^(1/a) 3^(4/b), b][[1]] As we want real numbers, we can delete the imaginary ...
Daniel Huber's user avatar
  • 47.3k
6 votes
Accepted

Why hasn't the minimum value of a+b been determined?

The following works in 13.3.1 on Windows 10. Minimize[{a + b, Reduce[9 == 9^(1/a) 3^(4/b) && a*b > 0, Reals]}, {a, b}] $\left\{2 \sqrt{2}+3,\left\{a\to ...
user64494's user avatar
  • 24.5k
3 votes
Accepted

Modifying `FindMinimum` to work for noisy functions?

I compiled your code and used Bayesian Optimization. I think,when dealing with noisy function, we should convert it into the deterministic equivalent or treat it as ...
Xminer's user avatar
  • 1,213
1 vote

How to speed up optimization?

Have you considered using Orthogonalize for this? This finds an orthogonal basis for the powers of x over [0,5] and then projects ...
flinty's user avatar
  • 23.9k
2 votes

How to speed up optimization?

This is a bit out there, but you can actually do this using the neural network facilities which opens up the possibility to use a GPU: ...
flinty's user avatar
  • 23.9k
0 votes

Could a minimization problem be easily converted into a NonlinearModelFit?

The standard approach (going back to at least 1935) for your linear model ($a+bx$) with a known covariance matrix is Generalized Least Squares (https://en.wikipedia.org/wiki/...
JimB's user avatar
  • 40.6k

Top 50 recent answers are included