Matt J

Last seen: Today

7.158 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
matlab Fit the third polynominal
This might be what you want: x=[0,12.5,25,37.5,50,62.5,75,87.5,100]; y=[10.0427, 10.3969,10.9316,11.5673,12.3015,13.1827,14.54...

ongeveer 10 uur ago | 0

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Answered
Finding face vertices of a polygon
My spatialgraph2D class might be applicable, assuming the polygon edges are non-intersecting: https://www.mathworks.com/matlabc...

ongeveer 11 uur ago | 0

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Finding face vertices of a polygon
You cannot do what you propose with just a list of vertex indices. You need the x,y coordinates of the vertices themselves. Give...

ongeveer 11 uur ago | 0

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Why can't I use the mae error with the Levenber-Marquardt algorithm?
Why can't I use the mae with the trainlm? Just a guess, but Levenberg-Marquardt presumes that a Jacobian can be computed at the...

ongeveer 12 uur ago | 1

Answered
clarification about first order optimality
It is because you have not invoked the options SpecifyObjectiveGradient=true and SpecifyConstraintGradient=true in your call to ...

ongeveer 18 uur ago | 0

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Answered
What optimization method can be used to solve the following optimization problem?
linprog would be appropriate. You could also use the problem-based framework to set up the problem. https://www.mathworks.com/h...

2 dagen ago | 0

Question

Let other applications use Matlab's version of the CUDA toolkit
I have an external piece of CUDA code that needs to know the path to the CUDA Toolkit in order to compile. Rather than installin...

2 dagen ago | 2 answers | 0

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Answered
Methods to Speed-up fsolve
If the solutions are expected to evolve continuously, it can save time to use the last result as the initial guess for the next ...

3 dagen ago | 0

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Answered
How to make Visual Studio 2013 visible to Matlab 2018a
Well, restarting Matlab did not help, but rebooting the computer did.

3 dagen ago | 0

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Question

How to make Visual Studio 2013 visible to Matlab 2018a
I have installed Visual Studio 2013 Professional under Windows 10 and I have successfully used it to write, compile, and execute...

3 dagen ago | 1 answer | 0

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Answered
Why is pagemtimes slower on GPU than a CPU?
I don't have a Matlab version that supports pagemtimes, but for the GPU version, it might be advisable to instead try pagefun(@m...

3 dagen ago | 0

Answered
fmincon constraining some variables and not others
Setting A(i,i) and b(i) as 0 seems a waste of CPU since fmincon() will probably keep using a constrain that actually is not. In...

3 dagen ago | 1

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Answered
i am trying to find coefficients a0 , an and bn but the output for bn seems wrong and will not simplify
Well, here is what I get for bn, >> bn bn = [ 17202483417667977/4503599627370496, 0, 5734161139222659/4503599627370496,...

4 dagen ago | 0

Answered
Convert Column vector into matrix
H=histcounts(coln,1:257); result=((1:10).'<=H).*(1:256);

5 dagen ago | 1

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Answered
lsqcurvefit bad fitting results
Probably the sqrt() operation in your model function. There is nothing preventing the algorithm from searching in regions where ...

6 dagen ago | 0

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Is it possible to add variables to my nonlinear constraints if they are not in the objective function?
Your initial guess x0=[20,20] contains only 2 elements but it should contain 5 because that is how many unknowns you have. If yo...

6 dagen ago | 0

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Answered
Running function on GPU for all combination of variables
Here's a loop-free method using ndgridVecs, https://www.mathworks.com/matlabcentral/fileexchange/74956-ndgridvecs but bear in ...

6 dagen ago | 0

Answered
construction of diagonal matrix of functions
This might be what you want. It assumes that f_1,2,3(x) work element-wise. function A=func(x) f1=f_1(x(1:end-1)); f2=f_2(...

6 dagen ago | 0

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Answered
construction of diagonal matrix of functions
function A=func(x,n) e=zeros(1,n-2); f1=f_1(x); f2=f_2(x); f3=f_3(x); A=toeplitz([f2,f1,e], [f2,f3,e]); ...

6 dagen ago | 0

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Running function on GPU for all combination of variables
In this case, I'd use parfor to descrease the simulation duration, but the size of this variable is quite large so I'd prefer to...

6 dagen ago | 0

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Answered
Optimization of a unknown vector variable
H1=sum(h1); H2=sum(h2); H3=sum(h3); obj=@(a,b) H1.*a.^2 +H2.*b.^2+H3; x0=[1,1]; lb = []; ub = []; Aeq = []; beq =[];...

7 dagen ago | 0

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Answered
Is it possible to find out an unknown variable within constraint which is not present in the objective for a optimization problem?
Yes. It is not a problem if your objective only depends on a subset of variables. However, you must pass the full unknown vector...

7 dagen ago | 2

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Answered
FSOLVE GIVES SAME VALUE
clc;clearvars;close all; format short g;format compact; tfinal=30; pars.D=0.00005611; pars.x2f=20; pars.Y=0.4; pars.beta=0....

7 dagen ago | 0

Answered
Linprog stopped because no point satisfies the constraints.
linprog is telling you that no solution exists, because there is no x that satisfies your constraints. Your problem must have a ...

7 dagen ago | 0

Answered
How can I straighten edges of calibrated images ?
Try setting the 'OutputView' option to 'valid' https://www.mathworks.com/help/vision/ref/undistortfisheyeimage.html#d122e205695...

8 dagen ago | 1

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Answered
lsqnonlin seems stuck at the same residual value,norm step and first order optimality for a while now
For a 3-variable problem known to have non-differentiabilities, it would make sense to use fminsearch instead of lsqnonlin. Ther...

8 dagen ago | 0

Answered
Optimization function based on different domain of optimized variables
Solve the problem twice, once with the constraint x1<=k and once with x1>=k, imposing the appropriate objective function in each...

8 dagen ago | 0

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Answered
Change white pixels to invisible
Shouldn't you have alphachannel = 1-double(all(image == 255, 3));

9 dagen ago | 0

Answered
Converting strings to operators
I can't tell if you really intend S to be a string vector because that dpesn't agree with the example you posted. If I assume it...

9 dagen ago | 1

Answered
optimization problem of areas
Your objective function Area2 is written to be a function of z, but nothing in sum( ( x.*dt(m(1):c(1)) ) ) depnds on z. Perha...

9 dagen ago | 0

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