Matt J - MATLAB Central
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Matt J


Last seen: Today Attivo dal 2009

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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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MATLAB AnswersFile ExchangeCodyHighlightsFrom 12/09 to 03/25Use left and right arrows to move selectionFrom 12/09Use left and right arrows to move left selectionTo 03/25Use left and right arrows to move right selectionUse TAB to select grip buttons or left and right arrows to change selection100%

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Risposto
polyshape not closing a circle
%gui = uifigure; %g = geoglobe(gui,"Basemap","satellite", 'NextPlot','add'); wgs84 = wgs84Ellipsoid("nm"); lat0 = 42.3601; l...

circa 9 ore fa | 0

Risposto
Why does the Code Analyzer flag this as an error?
Mathworks Support has classified it as a bug.

circa 14 ore fa | 1

| accettato

Risposto
How do you change the output dimension of a NN layer?
Should I flatten the inputs and then concatenate them similar to this example? Probably. See if the attached network does what...

1 giorno fa | 0

Risposto
Display a small matrix as a gray scale image
T2 =[ 0.4706 0.9804 0.8392 0.3216 0.9804 0.8392 0.3216 0.4706 0.8392 0.3216 0.4706 0.9...

1 giorno fa | 0

| accettato

Risposto
How to freeze specific neuron weights in a feedforward network during training process?
I don't think you can do it without the Deep Learning Toolbox. If you have the Deep Learning Toolbox, you can define a custom la...

2 giorni fa | 0

Risposto
Please help with this multiplication problem
You can multiply directly. Example: [m,n,r]=deal(3,4,2); A=rand(m,1,r); B=rand(1,n,r); C=A.*B; whos A B C

2 giorni fa | 0

| accettato

Risposto
sub2ind() errors out with NaN inputs - handled differently since R2024a
You can get the old behavior back if you need it, Sub2Ind([ 3 5 7], [ 3 3], [2 2], [1 nan]) function out=Sub2Ind(sz,vararg...

2 giorni fa | 0

Risposto
Non-linear constraints format for GA using solve function
I would formulate it as, N=numel(Pos_Input_mtx); problem.Constraints.c1=abs(Pos_Input_mtx(:)-Pos_Input_mtx(:)') >= (1-eye(N)...

3 giorni fa | 0

| accettato

Risposto
Summing function handles of multiple variables across one of the variables
Nesting function handles n-fold is going to be very inefficient, and is usually not a good idea. Usually, it is best to vectoriz...

3 giorni fa | 0

Risposto
Error using trainNetwork Invalid training data. For classification tasks, responses must be a vector of categorical responses. For regression tasks, responses must be a vector
Instead of using Matlab's dicePixelClassificationLayer, you can try the following custom output layer: classdef GeneralizedDice...

5 giorni fa | 0

Risposto
Ifft2 results do not match that of irfft2 in Pyhton
I'm not a Python user, but if rfft2 only gives you positive x-frequencies, I would imagine it also only gives you positive y-fre...

6 giorni fa | 0

Domanda


Three dots at the end of a line of code
Why does one of my lines of code have three dots enclosed in a box? What does it mean? Clicking on it does nothing.

7 giorni fa | 1 risposta | 0

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risposta

Risposto
Looking for linear system Ax=0 precision improvements
s=max(abs(A),[],1); x = null(A./s)./(s')

8 giorni fa | 0

Risposto
Finding x and y values of minimum z in 2-variable function.
The continuous minimum can't be at (5,2) as you claim. Direct evaluation shows that the value of z at (5.5,10) is lower. loopi...

8 giorni fa | 0

Risposto
Using fft and ifft with less frequencies than input points
What I would want to do, is to insert an N, f.e. N=100, but get an array 10001x1. %Grid Nx = 100; L = 10; dx = L/(Nx-1); ...

8 giorni fa | 0

Domanda


Why does the Code Analyzer flag this as an error?
Why does the Code Analyzer flag this code as an error? It runs fine: try error("It's bad") catch ME warning('Error...

8 giorni fa | 2 risposte | 0

2

risposte

Risposto
How to fastly calculate this real number matrix manipulation?
e=(1:A)'; I=reshape(e,1,1,[]) == repmat( e,1,B); Xp=permute(X,[3,2,1]); D=X./(X-Xp); D(I)=1; M = ipermute( prod(D,1) ,[...

10 giorni fa | 0

Risposto
How to solve the error generated while defining custom FFT layer?
Your predict() method is written to expect that the input X will be a cell array. It's not clear why you expect this, but you sh...

10 giorni fa | 0

| accettato

Risposto
How do I edit a loop to be able to store the variables and outputs used in each loop in a way which can be graphed?
D = 0.3 k = 0.0002 Rvalues = 10^4:10^5:10^8; nR=numel(Rvalues); X=nan(1,nR); for i=1:nR R=Rvalues(i); ...

10 giorni fa | 0

Risposto
reshape 4-dimension array
Download this File Exchange package, https://www.mathworks.com/matlabcentral/fileexchange/115340-block-transposition-permutatio...

12 giorni fa | 0

Risposto
Speed up this bottleneck line of code
If you can construct c in transposed form, there are some savings to be had, n = 10000; m = 5000; k = 20; a = rand(n,m);...

12 giorni fa | 0

| accettato

Risposto
nonlinear spline fit with unknown upper bound of interpolation domain
The upper bound is way larger than the fitted parameters at x < 6, causing an extremly large curvature at x > 6 which makes the ...

16 giorni fa | 0

| accettato

Risposto
Differentiating in one direction using FFT2
fft2(u) is equivalent to fft( fft(u,[],1) ,[],2), if that helps at all. Truthfully, it doesn't appear that you need to use fft2...

16 giorni fa | 0

| accettato

Risposto
need to vectorize efficiently calculating only certain values in the matrix multiplication A * B, using a logical array L the size of A * B
Is v much smaller than m or n? If so, one approach might be with an outer product decomposition: L=sparse(L); %if L was not pre...

17 giorni fa | 1

Risposto
shared colorbar for specific plots in tiledlayout
Using nestedLayouts from the File Exchange, https://www.mathworks.com/matlabcentral/fileexchange/161736-grids-of-tiled-chart-la...

18 giorni fa | 0

Risposto
MATLAB Optional Function Arguments
Using the arguments block is more robust, but I'm unable to find a way to make multiple inputs independently optional. The way ...

18 giorni fa | 2

| accettato

Risposto
Set number of rows in output variable using indexing within for loop, add variable to new table
I would like to put the two calculated variable columns directly after the variable column in the original table. And you want ...

19 giorni fa | 0

Risposto
What happens if the termination condition is satisfied before the constraint in matlab's fmincon?
The only time fmincon will stop without satisfying the constraints (within ConstraintTolerance) is if the MaxItertions or MaxFun...

19 giorni fa | 0

| accettato

Risposto
How to remove columns in very large matrices.
Use a sparse matrix, if applicable. matrix=sprand(1750000 , 2000, 1000/1750000); whos matrix tic; matrix(:,1:3:end)=[]; ...

19 giorni fa | 0

Domanda


Suppress uitable cell borders
In Excel, there are buttons to select particular spreadsheet cell borders and hide them. Is there an analogous way to suppress t...

20 giorni fa | 1 risposta | 0

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