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Alan Weiss


Last seen: 2 days ago

MathWorks

1,886 total contributions since 2011

I write documentation for MATLAB mathematical toolboxes, primarily optimization. I have also written documentation for PDE, statistics, symbolic math, and econometrics.

My pre-MathWorks job was with Bell Labs, primarily in mathematical models of data traffic, with a strong interest in parallel computation and in rare events (large deviations).

I do not provide private consulting. If you have a question, please ask on a public forum such as MATLAB Answers.

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Answered
How to get fzero to work on an array?
I don't know if this is what you wanted, but I got it to work by making a loop for fzero: x = .2:.1:.6; r = .3 + 3.*((x-.5).^2...

3 days ago | 0

Answered
How to formulate GA with plenty variables (e.g >24000 variables)
It seems that you have thousands of binary variables. If so, then indeed ga is not an effective solver for your problem. You wo...

3 days ago | 0

Answered
How to do curve fitting to a custom function with 7 fitting parameters?
There are examples related to this in Nonlinear Data-Fitting and possibly Fit an ODE. Alan Weiss MATLAB mathematical toolbox d...

3 days ago | 0

Answered
fmincon converges to initial value
I haven't looked at your problem in detail, but I suppose that the issue is related to those found in Optimizing a Simulation or...

3 days ago | 0

Answered
bayesopt with equality and inquality constraints
I believe that you have two errors in your formulation. As explained in Constraints in Bayesian Optimization, bayesopt attempts ...

9 days ago | 1

Answered
How to choose DiffMinChange value?
I suggest that you look at When the Solver Might Have Succeeded. In particular, https://www.mathworks.com/help/optim/ug/when-the...

9 days ago | 1

Answered
Solve optimization problem that iterates on parameters with constraints defined with numerical solutions to differential equations depending on those parameters
Perhaps the example Fit an Ordinary Differential Equation (ODE) can help. Alan Weiss MATLAB mathematical toolbox documentation...

9 days ago | 0

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Answered
Change the range of potential hyperparameters when optimizing hyperparameter choice using fitrensemble
Looking in the documentation for fitrensemble I find this: ---- Set nondefault parameters by passing a vector of optimizableVa...

9 days ago | 0

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Answered
help me to use a gamu/pareto to solve an optimization problem
Your three objective functions are t(1)(x(1) - x(4)),..., and your second condition contains the equations t(1)(x(1) - x(4)) = 0...

17 days ago | 0

Answered
Only feasible point for intlinprog
Sure, you are free to use the built-in 'savemilpsolutions' output function to collect the solutions, and eiither give a random o...

17 days ago | 1

Answered
Multi Objective Optimization with discrete variables ?
Yes, if you are careful to define the creation, mutation, and crossover functions so that all integer variables are integers, an...

17 days ago | 0

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Answered
how can I get 5 parameters in using the optimization tool of an equation
I would not write the sum of squares explicitly. Instead, formulate your problem as an EquationProblem and solve that. You can h...

17 days ago | 0

Answered
How I can solve multivariable optimization problem without Optimization toolbox?
I would solve this in a loop for X = 0, X = 1,..., X = 10. Alan Weiss MATLAB mathematical toolbox documentation

17 days ago | 0

Answered
Fsolve - Equation solved, inaccuracy possible.
I think that you might be going about this the wrong way. If you want to solve an ODE numerically, usually you should use ode45 ...

17 days ago | 0

Answered
Optimization problem with intlinprog
You see in the iterative display that the number of integer solutions is reported to be 0. That means that intlinprog did not ye...

28 days ago | 0

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Answered
how to solve a deflection problem in pavement surface using genetic algorithms.
There are many ways to solve such model-fitting problems. See these examples: https://www.mathworks.com/help/matlab/math/exampl...

28 days ago | 0

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Answered
fminunc stopped because it cannot decrease the objective function along the current search direction.
Please run with the CheckGradients option set to true. I think that you will find that you did not calculate the derivatives cor...

28 days ago | 0

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Answered
How do I include a user specified hessian function for fmincon?
If you read the documentation for Including Gradients and Hessians, you will see that the fmincon 'interior-point' algorithm doe...

1 month ago | 0

Answered
How can I make sure I am using the right settings for the fmincon function?
You really should slow down to learn the tool that you are using a little bit better. Try working through the Getting Started no...

1 month ago | 0

Answered
Truss optimization, genetic algorithm
That statement does not indicate an error. That indicates normal ending of the solver iterations. Congratulations! Alan Weiss ...

1 month ago | 0

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Answered
Optimisation toolbox (GA)
You might want to refer to the documentation for gamultiobj or to the documentation of multiobjective optimization. Alan Weiss ...

1 month ago | 0

Answered
Export results Optimtool app
To use optimtool, all variables need to be in one vector. See Writing Scalar Objective Functions. To export to the workspace, s...

1 month ago | 0

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Answered
I keep getting the error "NVARS" must be positive integer while implementing GA. please help....
I did not read your code in detail, but the line where you call ga is [x, err_ga] = ga(h, c, ga_opts); Look at the documentati...

1 month ago | 0

Answered
How to define the objective function to solve an optimization problem with Matlab?
If I understand you correctly, your objective function (the thing you are trying to minimize) is integer-valued. Small changes i...

1 month ago | 1

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Answered
Error with Fmincon nonlinear constraint
Try this, as documented: nlcon = @(x)deal([],F); Alan Weiss MATLAB mathematical toolbox documentation

2 months ago | 2

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Answered
How to get intlinprog to stop when the answer is good enough?
You can create an intlinprog output function to stop the optimizaiton when the objective function value goes below a set limit s...

2 months ago | 1

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Answered
Refining mesh size (by having very small mesh size) close to the semi-circular flaw tip - Maximum Principal Stresses and Maximum Shear Stresses
I really don't know, but it is possible that the legacy function adaptmesh would enable you to perform your calculation to the r...

2 months ago | 0

Answered
how can i plot this code into a banana solutiongraph?
Perhaps what you are asking relates to this example: https://www.mathworks.com/help/optim/ug/banana-function-minimization.html ...

2 months ago | 0

Answered
nonlinear optimization constraints problem
I suggest that you ensure that your initial point is feasible, and then insert code into your objective function that first eval...

2 months ago | 0

Answered
How to set up parameter estimation in fmincon
I'm not sure, but I think what you are asking is how to pass several arguments as control variables, and maybe how to pass extra...

2 months ago | 0

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