Community Profile

photo

Alan Weiss

MathWorks

Last seen: Today Active 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.

Statistics

All
  • Ace
  • Revival Level 3
  • First Submission
  • 36 Month Streak
  • Thankful Level 3
  • Knowledgeable Level 5
  • First Answer
  • Solver

View badges

Content Feed

Answered
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...

27 days ago | 0

Answered
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,...

28 days ago | 0

Answered
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...

1 month ago | 0

| accepted

Answered
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...

1 month ago | 0

| accepted

Answered
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 ...

1 month ago | 0

Answered
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...

1 month ago | 0

Answered
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...

1 month ago | 0

Answered
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...

1 month ago | 0

| accepted

Answered
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...

1 month ago | 0

| accepted

Answered
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 ...

2 months ago | 0

| accepted

Answered
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...

2 months ago | 0

| accepted

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

2 months ago | 1

| accepted

Answered
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('...

2 months ago | 1

Answered
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...

2 months ago | 0

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

2 months ago | 0

| accepted

Answered
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...

2 months ago | 0

| accepted

Answered
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...

2 months ago | 0

Answered
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...

2 months ago | 0

Answered
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...

2 months ago | 0

Answered
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...

2 months ago | 0

| accepted

Answered
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...

3 months ago | 0

Answered
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...

3 months ago | 0

Answered
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 ...

3 months ago | 0

Answered
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 ...

3 months ago | 0

Answered
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...

3 months ago | 0

Answered
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...

3 months ago | 0

| accepted

Answered
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...

3 months ago | 0

| accepted

Answered
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...

3 months ago | 1

| accepted

Answered
I want to solve this problem
You can use secondordercone by making a new variable , a linear objective , and another second-order cone constraint: Minimize ...

3 months ago | 1

Answered
SVM and KNN hyperparameter
Is this what you are looking for? fitcsvm hyperparameter options fitcknn hyperparameter options Alan Weiss MATLAB mathematic...

3 months ago | 0

Load more