Matt J

Last seen: Today | Active since 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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Answered
M^2 fitting for a Gaussian beam with measured data
Your post doesn't give much detail on what you are trying to do, but if you are just trying to fit a 1D Gaussian to the data in ...

12 hours ago | 0

Answered
Class property validator reports an error if no default value is set
I have the following class defintion which is using a validator function You're not using a property validation function anywh...

13 hours ago | 0

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Optimization problem with non convex constraints
Is there a way to write these constraints so that they could be feasible for fmincon, linprog? There is, but it is generally no...

21 hours ago | 0

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Using contours and inpolygon, an issue of unclosed contours
There's no way to define a unique shape based on knowledge of just the isocontour line cooordinates. This gives you the boundari...

1 day ago | 0

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mage segmentation of 3D X-Ray micro computed tomography images using Unet.
The examples here show basic steps for creating and training a Unet, https://www.mathworks.com/help/vision/ref/unet.html#mw_a26...

1 day ago | 0

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Why does this code give error?
As you can see, VecteurDirectionnel and S are the wrong sizes for matrix multiplication, whos VecteurDirectionnel S % Array ...

2 days ago | 0

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DNN training 3D Parameters
The parameters you mention experimenting with do not include all the training options (see below for a more complete list). You ...

7 days ago | 0

Answered
Store arrays of different size in each for loop itertaion
b=sparse(sz(:,1)'); kkkk = nonzeros( (A(:)>=b & A(:)<=b+100).*(1:numel(A))' );

7 days ago | 0

Submitted

Block transposition, permutation, and reshaping of arrays
Analogues for transpose(), reshape(), and permute() but where sub-blocks of the array are treated as scalar elements.

7 days ago | 5 downloads |

Question

Why is it that Line objects can be instances of two different classes? How can I use findobj to detect only chart primitives?
Using findobj, I have ended up with two arrays of Line graphics handles, load handleArrays hL hD However, the arrays do ...

7 days ago | 0 answers | 1

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answers

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How to modify subplots to create a new subplots?
close all H(1)=openfig('pac4.fig'); ax1=flip(findobj(H(1),'Type','axes')); H(2)=openfig('pvc4.fig'); ax2=flip(findobj(H(2)...

7 days ago | 0

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Answered
Store arrays of different size in each for loop itertaion
kkk=cell(4,1); for i=1:4 kkkk{i} = find(A>=sz(i,1) & A<=sz(i,1)+100); end kkkk=vertcat(kkkk{:});

7 days ago | 0

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Answered
Using imageDatastore to load Input image and get output as predicted image
and predict an image as output of the model. Labels are text scalar that are assigned to an image in a classification problem....

10 days ago | 0

Answered
Most time-efficient conversion from logical matrix to fixed-point vector
n = 1e6; % number of fi objects m = 16; % number of bits of each fi object tic; A = randi([0,1], [n m], "logical"); t1 = toc...

12 days ago | 1

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Answered
Tracking the variation of the distance between optimization variable and the optimal solution over the iteration time
function x_opt = locao2(h, C, BS_positions, alpha,x0) objective = @(x) -calculatePDF(x(1), x(2), h, C, BS_positions, alph...

14 days ago | 0

Answered
Help with getting drawnow to show one point at a time
The loop variable i is not being used, Perhaps you meant to have, for i = 1:numel(roll) plotOrientation(op, roll(i), ...

16 days ago | 0

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Answered
The sufficient and necessary conditon of fmincon funciton can find out the global optimal solution but not some other local optimal solutions
fmincon has no awareness of, and so does not consider, the function's global properties, like whether it is convex or not. It on...

16 days ago | 0

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Answered
What is the finite nature of MATLAB?
It is not the finite nature of Matlab, but rather the finite nature of an FFT. You are not transforming a true sinc function bec...

16 days ago | 1

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Answered
Overloading subsrefs for class and using it from another method in the same class
As an alternative to subsref or set/get, you could look at RedefinesDot, but I find that the newer, modular indexing can have su...

16 days ago | 0

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Answered
Overloading subsrefs for class and using it from another method in the same class
No, subsref is only called by indexing operations invoked outside the classdef. This design decision was to avoid triggering rec...

16 days ago | 0

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Passing Structure through fminsearch
If p is the unknown parameter vector, it must be passed separately from the fixed parameters, S.PHI=... S.TAU=... [p...

16 days ago | 0

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Submitted

ezplane
Plot an arbitrary 3D plane given its equation.

17 days ago | 1 download |

Answered
multiple 3D plane plotting
Using this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/161351-ezplane planedip = 30; planeazim = 12...

17 days ago | 0

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Answered
Why do i get "Error using vertcat Dimensions of arrays being concatenated are not consistent" while using fmincon to do nonlinear optimization
However, as i searched, it seems appear for error in matrix calculation. there really isnt matrix calcualtion in my codes Certa...

17 days ago | 1

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Answered
Is it possible to make a video play through of points showing yaw, pitch, and roll values?
Yes, you can use VideoWriter.

18 days ago | 0

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Volume of union and volume of intersection of convex hulls?
Use intersectionHull from this FEX download to find the intersection, https://www.mathworks.com/matlabcentral/fileexchange/3089...

18 days ago | 0

Answered
How can I define a custom loss function using trainnet?
If you have multichannel output, the loss function will give you an SSIM per channel, e..g, loss = @(Y,targets) 1-ssim(Y,target...

19 days ago | 0

Answered
MATLAB code of intersection
f=@(z) z(:,1:2)./z(:,3); t=(0:2:30)'; e=ones(size(t)); D=[cosd(t), sind(t), 0*e]; L1=cross(e*[0 0 1], D); L2=cross(e*...

20 days ago | 1

Answered
Constructing a 3D matrix out of single column coordinate data with a corresponding value
Let's call your Nx4 matrix XYZV. xyzv=num2cell(sortrows(XYZV,[3,2,1]) ,1); [I,J,K,V] =deal(xyzv{:}); I=findgroups(I); J=...

20 days ago | 0

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Answered
Constructing a 3D matrix out of single column coordinate data with a corresponding value
If you are trying to query velocity values at arbitrary 3D locations, do not use a 3D array. Instead, use scatteredInterpolant o...

20 days ago | 0