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Matt J


Last seen: Today
7,037 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Termination Conditions fmincon: Optimality
In the constrained case, the first order optimality metric, described here, https://www.mathworks.com/help/optim/ug/first-order...

13 hours ago | 0

| accepted

Answered
Solving "transposed" Lyapunov equation AX+X'B=Q
I don't know how large your system is, but if not super-large you could use func2mat, https://www.mathworks.com/matlabcentral/f...

13 hours ago | 0

Answered
Error using vertcat Dimensions of arrays being concatenated are not consistent.
Well, for example dXadt is 1x2 and dXedt is 1x1, so you cannot stack them on top of each other to form a new matrix. dXadt ...

18 hours ago | 0

Answered
Rowfun and sum of array elements based on start and stop position from another array
It works with loops but the size of my table makes it quite slow It shouldn't be. Even with several thousand table columns, a l...

21 hours ago | 0

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Answered
Rowfun and sum of array elements based on start and stop position from another array
So, how to achieve that simple operation with rowfun? I don't see rowfun as being part of the solution. Just pull the values ou...

21 hours ago | 0

Answered
Compatible Problem in Matlab: LineSearchType option is no longer valid in using optimset
options = optimset('LargeScale', 'off', 'HessUpdate', 'dfp','MaxFunEvals', MaxFunEvals, ... 'display', 'of...

22 hours ago | 0

Answered
Rotation of an xy coordinate system
Looks fine to me. When you rotate about the origin, the only point that stays fixed is the origin.

22 hours ago | 0

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Answered
How can I convert 100 X Y and Z coordinates generated randomly in the form of a 100x100x100 matrix
If you mean you want a 100x100x100 binary array A with one hundred randomly located entries where A(i,jk)=1, then A=false(100...

1 day ago | 0

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Answered
fmincon MATLAB function using gradient
Because of the discontinuity at x1=0 and x2=0, you need to optimize over each quadrant separately. s=[+1,+1; %quadrant signs ...

2 days ago | 0

Answered
Mean Variance portfolio selection with l1-norm
Sure. Minimizing a quadratic subject to linear constraints is exactly what quadprog is for.

2 days ago | 0

Answered
How to perform image registration on GPU
If you only need to register translation, you can use normxcorr2() which is GPU-supported https://www.mathworks.com/help/images...

2 days ago | 0

Answered
how to find coordinates of each brick corners using matlab
After applying imopen() like ImageAnalyst recommends, you could download pgonCorners and apply it as in this example in this exa...

2 days ago | 0

Answered
What is wrong with my for loop?
It seems clear that when i=j, the left hand side of K((j*s-j-1):(i*s-i-1), (j*s-j-1):(i*s-i-1)) = k(1:s,1:s); will be 1x1 wher...

3 days ago | 1

Answered
Drawing 4-sided polygons around objects
This will help to find the corners of the boxes. https://www.mathworks.com/matlabcentral/fileexchange/74181-find-vertices-in-im...

3 days ago | 0

Answered
Stop chatting, MATLAB!
Just a guess, but you might try going into Preferences>>General and unchecking the option to send telemetry info back to MathWor...

4 days ago | 0

Answered
How can we refer world coordinate to image coordinates??
You have world2Intrinsic() https://www.mathworks.com/help/images/ref/imref2d.worldtointrinsic.html

6 days ago | 0

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Answered
Cone constraints with mixed integer programming
My approach would be to reduce this to a 1-variable minimization over x(11) and solve that with fminsearch, [Combinations{1:10}...

8 days ago | 1

Answered
Find nonzero elements in 5x5 matrix (diagonal, vertical, horizontal line)
For example, to search for a column string, A =[ 1 4 4 4 5 3 1 4 1 4 5 ...

9 days ago | 0

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Answered
How can I fit multiple lines through a common y-intercept?
p=[x(:).^[1,0] ,0*x(:); 0*x(:),x(:).^[0,1]] \[y1(:);y2(:)]; m1=p(1) b=p(2) m2=p(3)

9 days ago | 2

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Answered
fmincon very slow for a small scale problem
Don't use Symbolic Toolbox operations. Remove all the sym operations and just convert fnsum to a numerical objective function.

9 days ago | 0

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Answered
Double summation of a matrix
The expression in your .jpg file, if it needs to be evaulated for all p,q would be SML=conv2(ML,ones(N+1),'same')

9 days ago | 0

Answered
Prevent a figure/axis from being made current manually
Like Walter mentioned, setting the figures HandleVisibility to off seems to do the job.

9 days ago | 1

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Answered
Double summation of a matrix
In recent Matlab, you can do sum(matrix,'all') or more generally you can do sum(matrix(:))

9 days ago | 0

Answered
Why Matlab tells the following A*A^T matrix is not a positive Semi-definite Matrix ?
Yes, it is positive semi-definite. But Matlab's ability to detect that is limited, because finite precision prevents it from com...

9 days ago | 0

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Question


Prevent a figure/axis from being made current manually
Is there a way to disable the ability of the figure window to automatically become the current figure when a manual user action ...

9 days ago | 2 answers | 0

2

answers

Answered
Why matlab live editor and matlab script gives different rank calculation result for the same matrix ?
Probably because you copy-pasted the values of M from the screen to one of the scripts.

10 days ago | 0

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Answered
How to rotate 3D cube so that one face is normal to a given axis
If I can choose the missing rotation angle freely, then here is one solution. % Centre of system coords_source_xyz= [-0.5,...

11 days ago | 0

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Answered
Fitting Data from a matrix to polynomial
A very relevant example: https://www.mathworks.com/help/curvefit/fit.html#bto_zh5-3

11 days ago | 0

Answered
How to solve a nonlinear equation?
[x,fval] = fzero( @(x) x^(8.5)+3*x.^2-3000,nthroot(3000,8.5))

11 days ago | 0

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