# 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.

**Content Feed**

Facing problem in solving simultaneous nonlinear equation with 3 unknowns

What @Dyuman Joshi says is true. However, your equations don't seem to make sense without upper and lower bounds on x. For examp...

1 hour 前 | 0

Assigning row names iteratively

The row names of a table cannot be non-unique, so having the names of the 7 days of the week repeat 52 times would not generate ...

2 hours 前 | 0

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Plotting a giant surface exceeding array limitations

First of all, you should consider downsampling from 40000 points to perhaps 400. Having very dense data beyond a certain point w...

14 hours 前 | 1

Partial Fourier transform of large sparse 3D array

There is at most 1 nonzero pixel in each x-y plane (first 2 dimensions) ... I'm thinking of doing 1D Fourier transform on each d...

1 day 前 | 0

Partial Fourier transform of large sparse 3D array

You can do the partial Fourier transforms by computing a set of partial DFT matrices: dftPartial=@(N,k)sparse(exp(-(2j*pi/N)*(0...

1 day 前 | 0

Adding more values to an array every loop

One possibility, y=nan(1,100); s=0; for k=1:numel(y) y(k)=2*k-1; s=s+y(k).^2; if s>40, y...

1 day 前 | 1

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My ellipse wont close after running the code .

Can't you just use the native spline() command? theta = linspace(0, 2 * pi, 8); t_x = 2*cos(theta); t_y = sin(theta); dt_x...

1 day 前 | 0

Newton Raphson to solve a system of non-linear equations

From the surface plot, the equations don't appear to have any solution, or at least no where near the vicinity you are searching...

1 day 前 | 0

Why is my gamultobj algorithm not working?

My guess would be that it is struggling to find feasible solutions to the nonlinear constraints (perhaps because they don't have...

3 days 前 | 0

Solve large number of independent systems with fsolve, where some systems do not have a solution

I see no reason why fsolve would "give up" if you've set MaxIterations and MaxFunctionEvaluations to Inf, regardless of whether ...

3 days 前 | 0

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Display long strings that include newlines in a table

I don't think there's a way. But you could write to an Excel file (e.g., with writetable) where multiline cells are possible. >...

3 days 前 | 0

Dot indexing is not supported for variables of this type.

Have you actually looked at the contents of device? Is it possible that MAI.GetDeviceByIndex(0) returns empty [] because someth...

3 days 前 | 0

understand in which function the field is filled

If ReportAggreg is created literally with an assignment statement of the form someStruct.ReportAggreg = something it should be...

3 days 前 | 0

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Can I define the relationship between input and output using the raw experimental data in MATLAB. somthing like this .

Yes, you have a choice of lsqcurvefit, fit, and various others.

3 days 前 | 0

How can I get X value by transforming the griddedInterpolant function?

Why not just, F=scatteredInterpolant(Y(:),Z(:),X(:));

3 days 前 | 0

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Is there any layer defined in matlab for sine activation function? Or else can we define the layer using functionLayer?

If it will not have any learnable parameters, you can use a functionLayer.

3 days 前 | 0

How can I use the returned sort index from the sort() function on a multidimensional array?

The easier way would be to use the attached modification of sort() which will simply return the output indices as lienar indices...

4 days 前 | 0

Loop around a toolbox

This runs: for N = 40:42 %<---shortened Daten=rand(N);%<-----added v = [1]; m = zeros(1,N); for n ...

4 days 前 | 0

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app class properties check

I imagine that you could define your own property validation function, https://www.mathworks.com/help/matlab/matlab_oop/propert...

4 days 前 | 1

Using Linear indicies to create new image

stats=regionprops(BW,'PixelIdxList'); Z0=false(size(BW)); for i=1:numel(stats) Z=Z0; Z(stats(i).PixelIdxLi...

4 days 前 | 0

How to extract all values along the third axis of a 3d-array using a logical 2d-array?

a = rand(10,10); a(5,5) = 10; b = a+rand(1,1,1000); br=reshape(b,[],size(b,3)); c = br(a == 10,:)

4 days 前 | 2

How can I graph these two equations in matlab?

One way, f =@(y) (y-4).*(2*y-y.^2); fplot(f); xlabel y; ylabel f(y) and similarly with the other function.

4 days 前 | 1

Common legend for each row of tiled layout

I could do nested tiled layouts, but that seems very cumbersome, especially when I have many more rows. Why? %% Make Layout Sk...

5 days 前 | 1

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is there a way to perform this task w/o using loops?

There are ways to do it without loops, but doing it without loops will be of no benefit to you. It will take more lines of code,...

5 days 前 | 1

Draw angled ellipses around clusters on PCA plot

Using polyshapes: ellipse=rotate( scale(nsidedpoly(1000),[2,1]) ,30); plot(ellipse)

5 days 前 | 0

Draw angled ellipses around clusters on PCA plot

See also elliipticalFit from the FEX downloadable, https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-t...

5 days 前 | 0

How can I stabilize the matrix left division (i.e. "\")?

You cannot. You must regularize the problem somehow and make the matrix non-singular.

6 days 前 | 0

Solving a quadratic optimization problem subjected to linear constraints

You can use lsqnonneg, xi=[0, 0.25, 0.5, 1, 1.2, 1.8, 2]'; fi= [2, 0.8, 0.5, 0.1, 1, 0.5, 1]'; phi=@(r) max(0, 1 - r).^4....

6 days 前 | 0

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Simple Indexing problem when creating a matrix

n=5; A=[0 60 120 180 240 300 360]; A=A+360*(0:n-1)'

6 days 前 | 0

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how to project a contour along a surface plane?

This looks applicable: https://www.mathworks.com/matlabcentral/fileexchange/8589-contourz?s_tid=srchtitle

6 days 前 | 0