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Matt J


5.957 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Multivariate Nonlinear Problem With vector & matrix unknown inputs
It's very easy to set up all the variables and constraints with the problem-based approach. f=optimvar('f',[9,16]); tau=optimv...

1 día ago | 1

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Answered
how to sum of column without sum function in a unit metrix
summa = summa + all(j,i);

1 día ago | 0

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Answered
(1/x)>2 . why x<(1/2) is Not the answer
Because, for example, x=-1 satisfies x<1/2 but does not saisfy 1/x>2.

1 día ago | 1

Answered
Linear interpolation of a 2d array to another 2d array
You are getting NaN's because some of the query locations where you have asked interpolation to be performed are outside the bou...

2 días ago | 0

Answered
How do i resolve
You must run whatever you are running on a Matlab installation that has one of those toolboxes listed.

2 días ago | 0

Answered
Is my code correct for finding the distance between a point and a surface?
It's largely correct, except that your function distsq is not differentiable at x=0. So, if there's a chance the solution might ...

3 días ago | 1

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Answered
Setting a Value in an Array in a Class
Use an ordinary method: classdef myclass_t properties my_array double end methods functi...

3 días ago | 1

Answered
How to solve linear equation for 3 unkowns using SOR in GPU
If you have the Parallel Computing Toolbox, you can make all the variables in your SORstep function A,B,C,D,E,F,G,H,I,J,K,L,om...

4 días ago | 0

Answered
in a loop like go back
first=find(a<=1, 1); a(1:first)

4 días ago | 0

Answered
Index in position 2 exceeds array bounds?
No, it is because of this line, ymax = max(n,j+1); %should be min But I agree with Rik that medfilt2 makes much more sense her...

4 días ago | 1

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Answered
Over-all sum value in fmincon for multiple x
Are you sure you only have 6 unknowns? In your earlier post, you had more. https://www.mathworks.com/matlabcentral/answers/4802...

4 días ago | 0

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Answered
How to fix the error (Index exceeds matrix dimensions)?
V and W only have a single column, but you are indexing them V(:,j) and W(:,j) at j>1.

4 días ago | 0

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Answered
round off problem in matlab
The values are not changed. They are just displayed to the screen to 4 decimal points. Use format long to see more precision. Al...

4 días ago | 0

Answered
Accessing structure by its name and looping through it
Why not organize the data as a struct array? Tests(1).Time = data1; Tests(1).Speed = data2; Tests(2).Time = data3; Tests(2...

4 días ago | 1

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Answered
How to solve linear equation for 3 unkowns using SOR in GPU
Not sure why you would be using an iterative method when an analytical solution is available. A=gpuArray.rand(3,3,512^2); b=gp...

4 días ago | 0

Answered
How to match an image subset in an image?
This might be applicable, https://www.mathworks.com/matlabcentral/fileexchange/33340-wncc-weighted-normalized-cross-correlation...

4 días ago | 1

Answered
Find minimum of an n variable function, n is like 800+
Depends on the surface. It's trivial, for example, if the surface is a hyperplane or a hypersphere.

4 días ago | 1

Answered
manipulation of (too) huge matrix (beyond the calculation capacity of my computer)
Actually, I am only interested in combinaison for which the addition of MllA+MllB are between 427.92105 and 428.49755 If you ha...

4 días ago | 0

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Answered
Error in fitting two parameters with lsqnonlin
[curve_fit_parameters,RESNORM,RESIDUAL,EXITFLAG,OUTPUT,LAMBDA,JACOBIAN] = ... lsqnonlin(@(k) fitcrit(k,time_exp, conc_exp, pa...

4 días ago | 0

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Answered
Mathworks Questions Resolved.
You should see a button next to the Answer allowing you to accept it. You can also Upvote the answer to award the answerer extra...

4 días ago | 0

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Answered
Finish lines in the image
Here is another method based on interpolation, and faster than dilating with large strels. [m,n]=size(A); [I,J]=find(bwskel(...

4 días ago | 1

Answered
Calling vectors from a user defined function?
You are missing a multiplication operator after the 2 in line 15.

5 días ago | 1

Answered
Steepest descent method algorithm
alpha is too big. Try alpha=0.001.

5 días ago | 1

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Answered
Image processing and sub-array summation
You can use sepblockfun from the File Exchange https://www.mathworks.com/matlabcentral/fileexchange/48089-separable-block-wise-...

5 días ago | 1

Answered
Finish lines in the image
Perhaps as follows, gapsize=36; A=imcrop(rgb2gray(imread('image.png'))); B=(imdilate(A,strel('sphere',ceil(gapsize...

5 días ago | 2

Answered
Optimization expression operation not supported
Maybe this is what you intended, C=cashFlows*bonds-obligations; E=C.'*triu(ones(8)); ALM.Constraints.Const1 = (E.*(1+Rates)')...

5 días ago | 0

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Answered
How to deblur an image after gauss filter and image registration?
Use imregtform to perform the registration on the blurred images and to obtain the optimal tform. Then apply the tform to your o...

6 días ago | 0

Answered
How to find the (x,y) combinations that make z=0?
You can use fimplicit https://www.mathworks.com/help/matlab/ref/fimplicit.html

6 días ago | 0

Answered
Plotting a for loop
C=nan(1,101); F=C; %preallocate for i = 0:100; C(i+1) = i; F(i+1) = (i*1.8)+32; end plot (C,F) xlabel(...

6 días ago | 0

Answered
fsolve with functions inside script
A=3; B=2; x0=1; fsolve(@(x)fun(A,B,x) ,x0); function F=fun(A,B,x) A=A; B=B; F=A+B/x end

6 días ago | 0

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