# 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**

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...

21 dagar 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...

2 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...

3 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,...

3 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...

3 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...

4 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 ...

4 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...

4 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...

4 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...

4 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...

4 månader ago | 0

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Supplying gradient for the subset of parameters

The short answer is no: there is no provision to provide analytic gradients for a subset of the parameters. I cannot think of a ...

4 månader ago | 0

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Is there a way to specify objective and constraint gradients when doing nonlinear optimization in the problem-based framework?

The problem-based approach calculates and uses gradients automatically for supported functions. However, to include gradients of...

4 månader ago | 0

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surrogateopt: output function

Try this. lb = [-3 -3]; ub = -lb; opts = optimoptions('surrogateopt','OutputFcn',@listout); obj = @(x)100*(x(2) - x(1)^2)^2 ...

4 månader ago | 1

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Passing values to PSO options

It works for me. Here is a little test script: fun = @(x)x(1)*exp(-norm(x)^2); lb = [-5,-5]; ub = -lb; opts = optimoptions('...

4 månader ago | 1

Do I need to normalize input parameters to Particle Swarm Optimization?

You don't usually need to scale your parameters, but many problems are solved more reliably if you do. See Center and Scale Your...

4 månader ago | 0

Possible bug with coneprog?

I think that you have identified a problem with the default options for trajectory problems: the optimality tolerance should be ...

4 månader ago | 0

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How can I save the output parameters for each step using lsqnonlin function?

Write an output function to save the values, either to a workspace variable or to a file. For syntax details, see Output Functio...

4 månader ago | 0

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I'm trying to apply conditional constraints on two variable with bayesopt

I think that you set the wrong name-value argument for your constraint function. bayesopt thinks that you are using an XConstrai...

4 månader ago | 0

parameter optimization in function

Try putting the following code at the end of yours: [dfinal,resnorm] = fminbnd(@(damping)trytofit(damping,x0,Acc_clean),0.00002...

5 månader ago | 0

Conversion from symbolic to matlabFunction and writing the result to a file

Would it be possible to do the following: create a multiplier variable m in addition to the other variables? syms Dm0 Ds0 Ds1 d...

5 månader ago | 0

Using Multistart in an unconstrained optimization

This type of problem is well-known to be numerically touchy, and to have multiple local minima. You really should give bounds, t...

5 månader ago | 0

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How does using same variables for both objective and constraints affect optimization results?

By changing the objective you also change the steps that fmincon takes to solve your problem. You should not be surprised that t...

5 månader ago | 0

Power balance in a microgrid

Usually the way to include this type of equality constraint is to use the approach shown in Integer and Logical Modeling. For an...

5 månader ago | 0

GA doesn't proceed to the next generation

Thank you for providing a complete problem, including all supportng function files. My main question is, why are you trying to ...

5 månader ago | 0

consider Z = x*y, a highly nonlinear relationship in MILP

Usually, when you have a MILP then you don't have variables multiply each other unless one of the variables is binary. For this ...

5 månader ago | 0

minimize linear objective function with quadratic constraint

Again, I am not sure that I understand you correctly. I do not know what your optimization variables are, and while you say that...

5 månader ago | 0

coneprog: Infeasibilities are satisfied in last step from iterative display but exitflag is still -2 (NoFeasiblePointFound)

I think that you have a misunderstanding about what the iterative display shows. For example, consider the documentation example...

5 månader ago | 0

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Changing optimization technique for Gaussian process regression model

I answered a similar question recently: https://www.mathworks.com/matlabcentral/answers/1751170-svm-and-knn-hyperparameter Alan...

5 månader ago | 0

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Not reproducibility in Random Forest with Hyperparameters

In creating your template for training, did you set the Reproducible name-value argument to true? Also, for your parallel option...

5 månader ago | 1

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