Matt J

Last seen: Today

6,887 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Dividing 3D image to 3D patches
Using mat2tiles, https://www.mathworks.com/matlabcentral/fileexchange/35085-mat2tiles-divide-array-into-equal-sized-sub-arrays ...

9 hours ago | 0

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Answered
How to apply Loop Function to this example
x=x0; for i=1:10 x=M*x; end

22 hours ago | 0

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Question on GPU Computing
Make sure you have updated drivers and make sure you restart your computer after their installation. Then use gpuDevice() to sel...

22 hours ago | 0

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How to find the length of a curve from a list of points using different length scales?
curveLength = sum(vecnorm( diff( [x(:),y(:)] ) ,2,2))

22 hours ago | 0

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Creating matrix with other matrix
[a(:,2:3),b(:),c]

22 hours ago | 0

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Answered
abcd is efghijk?
function C= circulant(x) n=length(x); C=zeros(n,n); C(1,:)=x; for i=2:n C(i, :)=[C(i-1, n) C(i-1,...

2 days ago | 1

Answered
parfor problem (broadcast variable)
There's never any gaurantee parfor will be faster, but I would modify the code as follows, B_Data=A_Data(:,2:5)/(0.6*2); B_ref...

2 days ago | 0

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Use inpolygon command for multiple polygon areas
Use discretize(), https://www.mathworks.com/help/matlab/ref/double.discretize.html Apply it separately to all of your xv's and...

3 days ago | 0

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For loop and array type
Best guess - your loop has reached a z for which allcsvfiles{z,1}(:,4) contains text. Use dbstop() to check.

3 days ago | 0

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Array of Structures (not structure array)
I don't know if this is something you explored in (2), but if so, I don't see why it wouldn't cover what you are trying to do. ...

3 days ago | 0

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Memory cost of multiplying sparse matrices
Here's another customized multiplication routine for tall A. I do not know how it compares to Bruno's in terms of speed, but it ...

5 days ago | 0

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Memory cost of multiplying sparse matrices
I believe it is simply because Matlab sparse matrix routines don't handle very tall & thin matrix dimensions very well. It beco...

6 days ago | 0

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Question

Convert a string array to a cell array of strings
Starting with a cell array of strings, >> C={'person','woman','man','camera','TV'}; I know that it is possible to convert to ...

6 days ago | 1 answer | 0

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Splitting a binary image into 2 parts
There is a small break in the curve which I assumed was supposed to indicate the desired dividing point between the right and le...

6 days ago | 0

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Answered
Plotting 3D network of points and their error ellipsoids
You can use scatter3() to plot the points and ellipsoid() to overlay ellipsoids around them. https://www.mathworks.com/help/mat...

6 days ago | 0

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Answered
fminsearch for existing simulation
As Walter said, fminsearch does not know or care how many lines of code are used to implement your objective function. Bear in m...

6 days ago | 0

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How to set 2 constrain bounds at the same time?
lb=[-10,-30]; ub=[+10,+30];

6 days ago | 0

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Answered
Is convhulln function work for N dimensional
The points you are inputting to convhulln do not form a solid shape in R^5. To within numerical precision, they all lie on a lin...

7 days ago | 0

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Sum each page of a 3D matrix and append sums as rows of new 2D matrix
D=permute(sum(C,1),[3,2,1])

7 days ago | 1

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Answered
Intlinprog function - problem
The optimal solution of a linear program can be discontinuous as a function of the problem data, particular when you have intege...

7 days ago | 1

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Answered
matrix manipulation and transposing
Because when v is a column vector and theta is a row vector, you get implicit expansion, https://blogs.mathworks.com/loren/2016...

7 days ago | 0

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How can I create matrix with parameter?
It seems like the kind of thing you would want a function for, rather than a matrix. RecoilEnergy=@(E,r) r.*(r<=E./(1+M./(2*E))...

7 days ago | 0

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Answered
Mean of a field of a struct
C=struct2cell(rmfield(S,'name')); A=cell2mat(reshape(C,1,4,[])); Averages = reshape( mean(A,1),4,[]).'

7 days ago | 0

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How create a cell array
It might be beter to have a struct, strArray=["scenario base","perturbazione veicoli","perturbazione strada","perturbazione ped...

7 days ago | 0

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How create a cell array
reshape( num2cell((1:24).'*ones(1,150)) ,[],1)

7 days ago | 0

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Answered
How to assign array values to object.object.property at once using deal?
No, you would have to do it in 2 steps, [Variables.Value] = deal (Data(:)); [SimIn(:).Variables] = deal (Variables);

7 days ago | 0

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Answered
Loop for square matrix
The FGETL command might be useful, https://www.mathworks.com/help/matlab/ref/fgetl.html?s_tid=srchtitle#br4x18h-6

8 days ago | 0

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Answered
Can't use mtimesx, "A C/C++ compiler has not been selected"
Run mex- -setup from the Matlab prompt, >> mex -setup and select one of the available compilers.

8 days ago | 0

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Answered
how to find the position of the max componunt
Call max() with two output arguments and only input the columns you are interested in getting the max for, [maxvalue, maxlocati...

8 days ago | 0

Answered
continuous representation (image generation) of discrete data set
You can use griddedInterpolant() if your x,y are gridded sample locations, or else scatteredInterpolant().

9 days ago | 0