# Johan Löfberg

### Linköpings Universitet

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Access variables from workspace in Interpreted Matlab Function

https://yalmip.github.io/YALMIP-and-simulink/ (with obvious change to do an initial call from work-space instead of setting up o...

2 years ago | 0

| accepted

larg number constraints in matlab

You're better off posting YALMIP specific questions on YALMIP specific forums https://github.com/yalmip/YALMIP/discussions (ne...

3 years ago | 1

Yalmip:SDP problem, run into numerical problem. Is the result credible, when the program run into numerical problem?

You should post YALMIP specific questions on the YALMIP forum. Short answer it depends. You will have to study the solution and...

3 years ago | 0

| accepted

YALMIP is not working with parfor loop

EDIT: Works now in newer MATLAB version! YALMIP does not work with parfor, and it cannot be fixed or circumvented. For YALMIP...

3 years ago | 0

Can I use ismember to compare a vector with a matrix

You should post YALMIP specific question to YALMIP specific forums https://groups.google.com/forum/?fromgroups=#!forum/yalmip

4 years ago | 0

You have NaNs in your constraints!, iterating, for loop

You are better off posting this question to the YALMIP Google groups, which you did but you never replied to the questions you r...

4 years ago | 0

| accepted

fmincon stopped because the size of the current step is less than...

Note that your model contains both a lot of numerical noise (things that you probably think is zero, but is on the order of 10^-...

5 years ago | 1

sdpvar matrix in Yalmip

Post YALMIP questions on the YALMIP google groups forum.

6 years ago | 0

inverse of sdpvar in Yalmip

Please use the dedicated YALMIP Google groups forum instead Answer: You basically cannot. Inverse operator is a horrible oper...

6 years ago | 0

YALMIP constraint: Writing constraints for the first and last position

Model = [y(1) == -2, y(end) == 2, ...] or simply assign those elements, y(1) = -2;y(end)=2;... YALMIP specific que...

7 years ago | 0

when I use yalmip throught matlab,it wil stop and appear run_ini_and_handle_events exception:'class mathworks::system::fatal exception:fatal exception'

You probably have cplex installed on your path. When yalmip sets up options, it calls the options creator for all available solv...

7 years ago | 0

The 'sdpvar' class does not support code generation.

https://yalmip.github.io/example/simulink/

7 years ago | 0

| accepted

Yalmip error : undefined function sdpvar

You must have failed with the installation such as unzipping and/or setting the path. Show us your path, and a "dir" performed i...

8 years ago | 1

| accepted

minimize||(R+S'QS)K + S'QT||

You haven't defined which norm you want to use. As you've tagged it with YALMIP, this is the YALMIP code for, e.g., 2-norm. ...

8 years ago | 0

| accepted

how to minimize the non-smooth function (- min(x,y) )

You can write this particular instance using linear programming. Note that you are minimizing max(-x,-y). The function max is a ...

9 years ago | 0

Solved

Times 2 - START HERE

Try out this test problem first. Given the variable x as your input, multiply it by two and put the result in y. Examples:...

9 years ago

CVAR Optimisation - Portfolio Weights and Iterations

CVar from data is linear programming representable, so trying to to solve it as a non-smooth nonlinear program using a nonlinear...

9 years ago | 0

Using 'fmincon' for Portfolio optimization with nonlinear constraint

Solving this using fmincon sounds like the wrong tool. First, the Sharpe ratio can be rewritten as a convex quadratic by suit...

9 years ago | 0

Error ! All rows in the bracketed expression must have the same number of columns.

Your blocks makes no sense. The (1,4) block is 2x1, but the (4,4) is 2x2, hence inconsistent width.

9 years ago | 1

| accepted

How do I compare the 2-dimensional "faces" of a 3-dimensional matrix?

Since your initial solve is simply a feasibility problem with the objective 0, what you are doing in the for-loop is that you ar...

9 years ago | 0

About optimization tool box question

Looks like a QP to me (i.e., you should not use fmincon, but quadprog, or some other quadratic programming solver) You have t...

9 years ago | 0

How can I solve a minimization with 3 linear constraints?

The formulation here looks like a bad idea. The last equality is a nonconvex equality constraints, which thus can be tricky for ...

9 years ago | 0

YALMIP constraint - All values should be equal

I believe you are implementing diff(P(2,:,:),[],3)== BTW, if possible, I recommend you to post YALMIP questions on the ...

9 years ago | 0

| accepted

mixed binary interger linear programming

Why are you empying the options structure? Anyway, works fine here optimize(Constraints,Objective) ... Total (root...

9 years ago | 0

what is the upper bound in ton/h for emissions to implement the CO2 emissions constraints

You should ask this on the YALMIP google groups forum instead

10 years ago | 0

low speed of 'ismember' function

If data is sorted, using ismembc could be a quick fix.

10 years ago | 0

linear programming to solve conditional equations

So you want S = min(V,Vmax)? This can not be represented in a simple linear program (unless it is maximized in the objective,...

10 years ago | 0

Solving a nonlinear programming using MATLAB?

fmincon is not applicable since you have integrality constraints. The model can easily be converted to a mixed-integer linea...

10 years ago | 0

| accepted

How to write matlab code for optimization of this equation ?

Do you absolutely have to use particle swarm optimization? I would conjecture that the optimal solution is to let all but one...

10 years ago | 0

| accepted

I am trying to run the following LMI codes on Matlab but it gives me an error called "Segmentation Violation Detected" and I do not know what is the meaning of this? Please any one help me solve the problem? See attached codes

It simply means that there is a bug in the MATLAB/LMILAB version you are using, so it crashes. You're not doing anything wrong. ...

10 years ago | 0