# Alan Weiss

### MathWorks

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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**Content Feed**

Output function for Simulated Anealing

You have mistaken the output of optimoptions for the optimvalues structure in simulate annealing. opts = optimoptions("simulann...

ungefär 6 timmar ago | 0

Optimisation of batch time using genetic algorithm and ODE solver

I do not know what the batch time and crystal size mean in your model, so I cannot tell you directly what to do. I can tell you...

10 dagar ago | 0

surrogateopt multi-objective function output

I do not understand why you want to use surrogateopt to help solve a multiobjective problem. I think that gamultiobj or paretose...

11 dagar ago | 0

GA initial solution not used in problem base solver

When using the problem-based approach you must pass initial points to ga using optimvalues. See https://www.mathworks.com/help/r...

14 dagar ago | 0

How to solve TSP using GA?

I think that it is useless to try to solve a TSP using ga, mainly because ga is so slow and unreliable compared to Optimization ...

16 dagar ago | 0

What is the difference between surrogateopt and bayeopt?

The algorithms have fairly complete descriptions: https://www.mathworks.com/help/stats/bayesian-optimization-algorithm.html ht...

16 dagar ago | 0

Unrecognized field name "ProblemdefOptions".

It sounds as if you are using the problem-based approach. To do so, you might need to specify some options when you call solve, ...

16 dagar ago | 0

How to plot non-quadratic functions?

This sounds like a multiobjective optimization problem. See Generate and Plot Pareto Front and, if you have Global Optimization ...

ungefär 2 månader ago | 0

How do I iterate f(x)

Is this what you are looking for? f = @(x)exp(x) - 2 - x - x.^2./2; t = linspace(0,5); plot(t,f(t)) OK, there is a root in t...

ungefär 2 månader ago | 0

How do I solve this system of non-linear equations using fsolve?

I don't know if this is helpful, but I suspected that fsolve was having trouble because of the scaling of your variables; everyt...

ungefär 2 månader ago | 0

How to display the value of a specific component of the objective function after computation is done?

I'd be very interested to know what you think of the nuclear fuel disposal example. But to answer your question, let's look at ...

2 månader ago | 0

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How to make the initial population in genetic algorithm fixed?

In addition to what Walter said, you can set the global random seed. rng default % Or rng(seed) [x,fval] = solve(problem,"Solv...

2 månader ago | 1

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Setting Pareto FronI want to set the Pareto Front using genetic algorithm

You can take a larger population. For example, options = optimoptions('gamultiobj','PopulationSize',300); Make sure to pass op...

2 månader ago | 0

Gamultiobj takes too long to run. Is there a workaround?

I am sorry, but I do not have time to understand your model in detail. However, I notice that you are using the problem-based ap...

3 månader ago | 0

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how to solve a multi-objective nonlinear optimization problem with constraints ?

For an example that optimizes the solution of an ODE using optimization variables, see Fit ODE Parameters using Optimization Var...

3 månader ago | 0

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Which optimization method is better for problems with random steps

In addition to what the other answerers have described, there does exist an optimization solver that can deal with stochastic ob...

3 månader ago | 0

Optimization problem code sos please help

Have you seen the Problem-Based Optimization Workflow? This approach allows you to create optimization variables as symbolic-typ...

3 månader ago | 0

how to use parfor for optim constraints?

Unfortunately, your version of Optimization Toolbox does not have the latest upgrade which uses "static analysis" to speed the c...

3 månader ago | 1

On which data is the ML model trained after hyperparameter optimization /Application of trained ML on new training data

With the settings you show, the software does not perform any cross validation. You need to set the OptimizeHyperparameters argu...

4 månader ago | 1

What is the output when Particle Swarm Optimization exceeds MaxTime

I believe that the code returns the point giving the best (lowest) objective function value encountered. Alan Weiss MATLAB mat...

4 månader ago | 0

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Genetic algorithm only works with integer constraints..

Yakov, your report indicates that the nonlinearly-constrained problem is being solved in the usual way: having very few iteratio...

6 månader ago | 1

why doesn't the gamultiobj function give me the output of the algorithm?

Your script worked for me. I attach the result. Using these commands, I also got a plot of the Pareto front. opts = optimoption...

7 månader ago | 0

GA - objective and constraints have to run the same expensive function

This is a difficult problem because of the way that ga calls functions, both fitness and nonlinear constraint. For most solvers,...

7 månader ago | 0

A problem in official website 'Least-Squares (Model Fitting) Algorithms'

Thank you for pointing out this long-standing error in the documentation. I will fix the error as soon as practicable. Alan Wei...

7 månader ago | 0

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Why is fmincon not finding the right solution?

Your mistake is trying to use fmincon to solve a problem with integer constraints. fmincon does not apply to this type of proble...

7 månader ago | 0

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What does useParallel doesn't work with Automatic Differentiation means and how do I fix it?

This is not a problem, this is a notification from internal algorithms. You are using the problem-based approach with supported ...

7 månader ago | 0

Spacecraft trajectory optimization with GA in Matlab (on/off constant thrust)

You might be interested in this example: Discretized Optimal Trajectory, Problem-Based. The problem formulation is different tha...

7 månader ago | 0

I want to find 4 constant with used 1 eq

This is an underdetermined problem, meaning there are many different values of x1, x2, x3, and x4 that work. For example, choose...

7 månader ago | 0

Trouble with plotting iterations in patternsearch optimization

I think that what is going on is that you have nonlinear constraints in your problem. When there are nonlinear constraints, patt...

7 månader ago | 0

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Setting conditions for optimization variables

x = optimvar('x', 100, 'LowerBound', 0); ub = Inf(100,1); ub(1:10) = zeros(10,1); x.UpperBound = ub; showbounds(x) It would...

7 månader ago | 0

| accepted