Johan Löfberg

Linköpings Universitet

Last seen: 5 dagar ago | Active since 2012

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Answered
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...

nästan 2 år ago | 0

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Answered
larg number constraints in matlab
You're better off posting YALMIP specific questions on YALMIP specific forums https://github.com/yalmip/YALMIP/discussions (ne...

mer än 2 år ago | 1

Answered
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...

ungefär 3 år ago | 0

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Answered
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...

ungefär 3 år ago | 0

Answered
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

mer än 3 år ago | 0

Answered
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...

nästan 4 år ago | 0

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Answered
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^-...

ungefär 5 år ago | 1

Answered
sdpvar matrix in Yalmip
Post YALMIP questions on the YALMIP google groups forum.

mer än 6 år ago | 0

Answered
inverse of sdpvar in Yalmip
Please use the dedicated YALMIP Google groups forum instead Answer: You basically cannot. Inverse operator is a horrible oper...

mer än 6 år ago | 0

Answered
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...

mer än 6 år ago | 0

Answered
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...

mer än 6 år ago | 0

Answered
The 'sdpvar' class does not support code generation.
https://yalmip.github.io/example/simulink/

mer än 6 år ago | 0

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Answered
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...

mer än 7 år ago | 1

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Answered
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. ...

mer än 7 år ago | 0

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Answered
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 ...

mer än 8 år 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:...

nästan 9 år ago

Answered
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...

nästan 9 år ago | 0

Answered
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...

ungefär 9 år ago | 0

Answered
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.

ungefär 9 år ago | 1

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Answered
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...

ungefär 9 år ago | 0

Answered
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...

ungefär 9 år ago | 0

Answered
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 ...

ungefär 9 år ago | 0

Answered
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 ...

ungefär 9 år ago | 0

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Answered
mixed binary interger linear programming
Why are you empying the options structure? Anyway, works fine here optimize(Constraints,Objective) ... Total (root...

ungefär 9 år ago | 0

Answered
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

mer än 9 år ago | 0

Answered
low speed of 'ismember' function
If data is sorted, using ismembc could be a quick fix.

mer än 9 år ago | 0

Answered
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,...

mer än 9 år ago | 0

Answered
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...

mer än 9 år ago | 0

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Answered
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...

mer än 9 år ago | 0

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Answered
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. ...

nästan 10 år ago | 0