Matt J
Professional Interests: medical image processing, optimization algorithms PLEASE NOTE: I do not read email sent through my author page. Please post questions about FEX submissions in their respective Comments section.
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Content Feed
Weird unexplainable results when fitting gaussian curve
You need bounds to regularize the problem, load data [~,g]=fit(x(:),y2(:),'gauss1'); R2=g.rsquare [~,g]=fit(x(:),y2(:),...
1 dag ago | 1
| accepted
Write a MatLab script to plot two ellipses using the plot function
As an example, here is a way to plot an unrotated ellipse of known major/minor axis lengths a,b. a=5; b=3; %major/minor axes ...
1 dag ago | 0
Does lsqnonlin handle a matrix objective function?
The matrix dimensions of the objective function output can be whatever you wish. It doesn't affect anything. The initialGuess c...
1 dag ago | 1
I need to run code written for NVIDIA GPUs with at least 8gb of RAM
According to this, https://hub.docker.com/r/mathworks/matlab campus-wide licenses are "already configured for cloud use".
1 dag ago | 0
Question
Is there a way to compute the n-th symbolic derivative of a function where n is also symbolic?
Is there a way to compute the n-th symbolic derivative of a function, where n is also a symbolic variable? The following does no...
1 dag ago | 1 answer | 0
1
answerGiven a taylor series of a function f, how do I get the original function f
syms x k f = symsum(x^k/factorial(k),k,0,Inf)
1 dag ago | 0
How to obtain all permutations of multiple cell arrays?
Using this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/115340-block-transposition-permutation-and-reshap...
2 dagen ago | 0
How to obtain all permutations of multiple cell arrays?
This is better because the for loop is only 6 iterations long. A={'a1'; 'a2'; 'a3'}; B={'b1'; 'b2'}; C={'c1'; 'c2'; 'c3'; 'c4...
2 dagen ago | 0
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Vectors must be the same length
i = gradient(q(:, 1),t); % Current derivative U_R = R * i; % Resistor's voltage U_L = L * gradient(i,t); ...
3 dagen ago | 1
| accepted
affine3d used for pure rotation causes translational misalignment
I don't really understand how your posted images show that something is wrong. It shows that the image has changed after the war...
4 dagen ago | 0
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Non linear fit extremely bad : what am I doing wrong ?
There are ways to derive an accurate x0 more systematically, e.g., rng('default') t = 0:0.02:10; x = t.*sin(2*pi*1*t) + 0.1*ra...
4 dagen ago | 0
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How to avoid counting elements in each row of matrix multiple times?
Xedges=linspace(Xmin,Xmax, Nbin+1); Yedges=linspace(Ymin,Ymax, Nbin+1); N=0; for i=1:height(X) deltaN = histcounts...
5 dagen ago | 0
How to put different size vectors to one matrix or mat file?
To save to a .mat file save filename d1 d2 d3 d4 To retrieve them, packaged in a struct variable, S=load('filename'); To wri...
5 dagen ago | 1
| accepted
finding the value of a corresponding column in matrix
models = A(A(:,1)==40,2)
7 dagen ago | 0
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lsqcurvefit answer upon termination?
You can use a nested OutputFcn, like in this example, https://www.mathworks.com/help/matlab/math/output-functions.html#bsgpq6q-...
7 dagen ago | 0
| accepted
Newton Raphson gives answers divided by 0
Raw Newton-Raphson is a pretty terrible method, but I assume you'll tell us you have no choice... [f,M]=preanalysis(); %Symbo...
8 dagen ago | 0
Adding elements to matrix
A=[1 2 3 4 5 6 7 8 9 10] B=[reshape(A,2,[]); zeros(1,numel(A)/2)]; B=[0,B(:)'] %the result
8 dagen ago | 1
| accepted
What does MATLAB actually do when switching precisions?
I don't know Julia, but I don't believe the binary decomposition was done correctly. Below is the way to do the binary decomposi...
8 dagen ago | 2
| accepted
lines that meet each other
You can use, https://www.mathworks.com/matlabcentral/fileexchange/93470-intersections-of-multiple-2d-lines-or-line-segments
9 dagen ago | 0
How to compute integrals on the GPU using trapz function
You cannot use trapz within gpuArray.arrayfun, but I don't think you really need it. On my computer, the following takes about 3...
10 dagen ago | 0
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augmentedImageDatastore for image segmentation
Supply the training data in numeric form: X_training = rand([224 224 3 200]) ; %Fake Y_training = rand([224 224 1 200]) ; %Fak...
10 dagen ago | 1
| accepted
Interpolation to arbitrary points on a patch plot
For example, F=scatteredInterpolant(msh_1.xy, q); interpolatedValues = F({[0.68,1.87],0:0.2:1})
10 dagen ago | 0
When eigs uses a custom function as input, it cannot compute an eigenvalue near a specified sigma
n = 10; A = randn(n); A = A + A'; E1=eigs(A,5,'sa')'; sigma = E1(2)+1; E2=eigs(A,5,sigma)'; E3 = eigs(@(x) (A-s...
11 dagen ago | 0
solving quadratic roots in matlab
Hint: You should consider applying the quadratic formula.
11 dagen ago | 0
how to create image data store? I do not have clarity regarding the arguments in ImageDataStore as studied from the website
Matlab does not understand (and neither do we) how a single "test1.tif" is supposed to specify labels for all of your images. Th...
11 dagen ago | 0
Running into issue using fsolve
There are no errors in what you've shown, but it is peculiar that you have one optimization (with fsolve) nested inside another ...
11 dagen ago | 0
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How to ask Matlab ga to continously regenerate individuals until they all satisfy user defined constraints prior to fitness evaluation
The way to handle that is to have the fitness function skip the FE modeling and return Inf (or some large penalizing value) if t...
12 dagen ago | 0
| accepted
Efficiently handling extremely large matrices (N x N) in MATLAB (e.g., N = 137 million)
Could you provide examples of using sparse matrices You give us wide latitude on what the example can be be, so here is one: A...
13 dagen ago | 0
Fast dataset manipulation in MATLAB
The implementation that you wrote first, R = [cos(theta) -sin(theta); sin(theta) cos(theta)]; bary = R' * (y - p); is alre...
13 dagen ago | 1
| accepted