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Matt J


Last seen: Today
6,359 total contributions since 2009

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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Answered
Any idea how to do and represent ttest results on box plot?
Usually, I just overlay them in powerpoint. But if you must automate this, one not too difficult way would be to use the line co...

11 hours ago | 0

Answered
changing a group of numbers in a vector
As an example, >> cycles=[0,1,0,1,0,1]; %3 cycles >> A=repelem(cycles,3) A = Columns 1 through 16 0 0 ...

2 days ago | 0

Answered
How to replace a vector element with a value not equal the other vector values?
function sudokuRow = fillSudokuRow(sudokuRow) idx=(sudokuRow==0); sudokuRow(idx)=func(sudokuRow(~idx)); end

2 days ago | 0

Answered
Passing parameter values found in lsqcurvefit to be initial values for parameter estimation in another function
Some possibilities, Combine the code from both fitting steps into a single script. That way you will have direct access to the ...

2 days ago | 0

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Question


Is there a danger in renaming a Matlab install folder
I have Matlab R2019b installed under Windows 10 in the usual place, C:\Program Files\MATLAB\R2019b but I would now like to ren...

2 days ago | 2 answers | 1

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answers

Answered
Speeding up nested for-loops when vectorization seems to fail
Getting rid of repmat (requires R2016b or later) and working with single float precision will get you some speed-up. In doubles...

4 days ago | 0

Answered
Speeding up nested for-loops when vectorization seems to fail
I tend to think you should be using scatteredInterpolant rather than implementing your own interpolation routine with loops.

4 days ago | 0

Answered
lsqcurvefit does not match data
Your model is clearly wrong, assuming that the given data is valid. In your current model, saturation is always 0 when displacem...

4 days ago | 0

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Answered
Row & Column Wise Normalisation
For a non-negative square matrix, the attached article mentions necessary and sufficient conditions (p. 3, Theorem 1) both for t...

4 days ago | 2

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Answered
How to move programmatically existing datatip
Maybe you can use the advice here, https://www.mathworks.com/matlabcentral/answers/100545-how-can-i-programmatically-control-mo...

5 days ago | 1

Answered
How to solve Too many input arguments error? Error in Fminsearch (line 200) fv(:,1) = funfcn(x,varargin{:});
This fh handles should be, fh{n}= @(x)vpe(x,p,MSM(:,n),erps(:,n),n);

5 days ago | 0

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Answered
A is a matrix of size 32*32.I want to subtract elements of each 4*4 block of A from their respective 4*4 means
out = blockproc(A,[4 4],@(x)mean(x.data(:))); result = A - repelem( out , 4,4);

5 days ago | 0

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Answered
Reducing repeated elements in an array by a factor
Another method, one which avoids for-loops inherent in cell2mat, V=[1,2,2,2,0,2,2,2,5,5,5,5,5,5,6,6,6]; N=3; X = cumsum...

5 days ago | 0

Answered
The support on here is horrible, does anyone have an api for the function calls? I'm tired of searching only to find examples of what I don't need.
Matlab Answers is a discussion forum, not a documentation browser. If you want to find documentation, start here, https://www.m...

7 days ago | 2

Answered
How to use fimplicit with a symbolic function
Using matlabFunction, you can derive a non-symbolic version of your circle equation expression from the symbolic version, >> ci...

7 days ago | 0

Answered
How can I get the elements from a matrix and use them as the coordinates in another matrix
D = C( sub2ind( size(C), W(:,1:end-1), W(:,2:end) ) ), sum(D,2)

7 days ago | 0

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Answered
A class to simulate missing arguments in function calls
The main drawback is that one must always use myfeval, which is not very readable. Yet another solution, which might address th...

8 days ago | 0

Answered
Multiple selection of an array
You can use sepblockfun downloadable from here https://www.mathworks.com/matlabcentral/fileexchange/48089-separable-block-wise-...

8 days ago | 0

Answered
A class to simulate missing arguments in function calls
Clearly, I would have to check for each input argument to be ~isempty(), or ~isnan(), which could be another technique. However,...

10 days ago | 0

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Answered
A class to simulate missing arguments in function calls
Seems to me that you can effectively accomplish what you want by defining a trivial class with no properties or methods, classd...

10 days ago | 0

Answered
Evaluating a complicated integral in Matlab gives NaN
Your integrand has a singularity at psi = pi/2. So perhaps try, f2(i) = integral(f1, 0, pi/2*(1-eps), 'ArrayValued', true);

11 days ago | 1

Answered
How to find "rectangular" corners?
Use pgonCorners from the File Exchange (Download). It applies to any convex polyhedron. numVertices=4; corners=pgonCorners(I...

12 days ago | 1

Answered
How can I change the 'MaxIterations' option in matlab 'createOptimProblem('fmincon',..........)'
You need to do this, opts=optimoptions('fmincon', 'MaxFunctionEvaluations',3000); problem = createOptimProblem('fmincon','x0...

12 days ago | 1

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Answered
Inconsistency in the definition of two geometric transformation matrices (tform)
The second form is the one expected by maketform. The only difference between the two conventions is that with the first, the tr...

12 days ago | 0

| accepted

Submitted


Find vertices in image of convex polygon
Estimates the corner points of a pixelated convex polygon having a known number of vertices.

12 days ago | 6 downloads |

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Answered
How can I find the coordinates of the top and bottom end plate and calculate the height?
The FEX submission pgonCorners (Download) can be used to find approximate corners for each of the vertebrae. Once you have the c...

12 days ago | 0

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Answered
How to get the maximum value of an implicit function?
I believe this method does not allow me to change the number of points in X, It does, e.g., f = fimplicit(fun,[0,40,0,9],'Mesh...

13 days ago | 0

Answered
How to avoid looping of anonymous function?
You could make it the end-user's responsibility to enter the function in anonymous form, >> f=input('Enter anonymous function: ...

13 days ago | 0

Answered
Fit image datapoints to curve
You would use a 2D version of an Iterative Closest Point (ICP) algorithm. This FEX contribution appears to have one: https://ww...

14 days ago | 0

Answered
Write a script that calculates the ​​user produced polynomial. The polynomial can be input until the user decides to terminate the program.
If you have the Symbolic Math Toolbox and wish to manipulate the polynomials in symbolic form, you can use poly2sym, >> p = inp...

19 days ago | 1

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