Matt J

Last seen: Today

7.013 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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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...

25 minutos 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 ...

alrededor de 1 hora ago | 0 answers | 0

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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.

1 día 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,...

1 día 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

1 día ago | 0

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

1 día ago | 0

Answered
fsolve function give poor results for multiple equations
Your equations are linear, so there is no reason to be using fsolve. I was able to obtain the coefficient matrix A for your line...

1 día ago | 0

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Answered
Why do I only have an output of zeros for the 1 X 800
We cannot run your code, but a good debugging strategy would be to pause execution at this line, Kr_eff = ((1./mso).*sum(S.*(Ks...

1 día ago | 1

Answered
Nonlinear inequality in GA optimization with integer constraints
In the code you have shown for POWER_CONSTRAINT(~), it does not make sense that POWER does not depend on the input, but rather o...

1 día ago | 0

Answered
I know how to divide my 256x256 image into 16x16 blocks using mat2cell. Now I want to access those 16x16 blocks successively to further divide them into 4x4 blocks.
Using mat2tiles https://www.mathworks.com/matlabcentral/fileexchange/35085-mat2tiles-divide-array-into-equal-sized-sub-arrays ...

1 día ago | 0

Answered
Generate a 100000x100000 matrix that takes less time and memory
Seems to me the whole code can be replaced by, function [a,ed] = Random_graph_genar_function(nodes, connectivity) a=logi...

2 días ago | 0

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Answered
Randomized Groups of Array
Ex. I have 250 numbers and I want them in 50 groups of 5 reshape( randperm(250) , 5,50) or 25 groups of 10, reshape( randpe...

2 días ago | 0

Answered
How to solve explicit equation of ellipse
If you convert the ellipse to its polar representation https://en.wikipedia.org/wiki/Ellipse#Polar_form_relative_to_center tha...

2 días ago | 1

Answered
How to find the solutions to a set of linear equations?
You can easily trap the point where NaNs are introduced using >>dbstop if naninf https://www.mathworks.com/help/matlab/ref/dbs...

3 días ago | 0

Answered
Efficient number occurence count
In this situation, accumarray will be faster than histcounts, but still not as fast as the for-loop, tic; hc=accumarray(num(:)...

4 días ago | 1

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Answered
Registation of two images in '.mat' format
With monomodal registration, it works fine for me, [optimizer, metric] = imregconfig('monomodal'); but I should mention that t...

4 días ago | 0

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Answered
construct a two level optimisation problem has fmincon solver for lower level and genetic algorithm for upper level
You are passing a variable called xl to LLConstraint(), but xl is not used anywhere within that function. The function is theref...

4 días ago | 0

Answered
Efficient number occurence count
I want to efficiently count the number of occurences of numbers between 1-numel(num) in a Matrix If that's really what you want...

4 días ago | 0

Answered
Using fsolve with multiple unknowns
...but unsure on the syntax for a problem like this. The syntax does not change. It is simply that your equation expressions w...

4 días ago | 0

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Answered
Array value replace when change in row
A=randi([0,1],7,10); %Example [m,n]=size(A); [~,idx]=max(A,[],1); out = sparse(idx,1:n,1,m,n) ; A, full(out)

4 días ago | 0

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Answered
Create column vector with same length as a matrix(6x6).
Taking the question literally, one solution would be, (1:6).' but I feel there must be missing information.

4 días ago | 0

Answered
Name-Value Pairs error
If you use inputParser, you can define validation functions https://www.mathworks.com/help/matlab/ref/inputparser.html#d122e665...

4 días ago | 0

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Answered
How to solve non-linear integer problems (MINLP/INLP)
You will have to use ga() in the Global Optimization Toolbox.

4 días ago | 0

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Answered
How to code my own Reshape function without using the built in reshape()??
Hint: Notice the effect of doing things like this: A=nan(3,4); A(:)=1:12

5 días ago | 0

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Answered
Fit the Data to a Quadratic Function with a y-offset (y = b+mx^2) error
I get no error messages when I run your code. However, you do not need fit() to perform this fit. You can just use polyfit, p=p...

5 días ago | 1

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Answered
Fsolve cannot continue error
The error message is complaining about your objective function, not about FSOLVE. Make sure your objective function equil() is w...

5 días ago | 0

Answered
unconstrained nonlinear optimization problem
Still, there are no constraints, so I think you should be using fminunc. Also, your revised objective function is not differenti...

5 días ago | 0

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Answered
Problems with a for loop
num2str(ck-1)

5 días ago | 0

Answered
Fill a nxm matrix with vectorised expression
No, there is no way to vectorize an element-wise function generically, without considering the specifics of the function. You ca...

6 días ago | 0

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Answered
Question about a statistics problem
I think you should just do, u = rand(sample_size,loop_times); number_of_success = sum(u<trueVal)

6 días ago | 0