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Matt J


5,943 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
How to solve linear equation for 3 unkowns using SOR in GPU
Not sure why you would be using an iterative method when an analytical solution is available. A=gpuArray.rand(3,3,512^2); b=gp...

13 hours ago | 0

Answered
How to match an image subset in an image?
This might be applicable, https://www.mathworks.com/matlabcentral/fileexchange/33340-wncc-weighted-normalized-cross-correlation...

14 hours ago | 1

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Find minimum of an n variable function, n is like 800+
Depends on the surface. It's trivial, for example, if the surface is a hyperplane or a hypersphere.

14 hours ago | 1

Answered
manipulation of (too) huge matrix (beyond the calculation capacity of my computer)
Actually, I am only interested in combinaison for which the addition of MllA+MllB are between 427.92105 and 428.49755 If you ha...

16 hours ago | 0

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Answered
Error in fitting two parameters with lsqnonlin
[curve_fit_parameters,RESNORM,RESIDUAL,EXITFLAG,OUTPUT,LAMBDA,JACOBIAN] = ... lsqnonlin(@(k) fitcrit(k,time_exp, conc_exp, pa...

16 hours ago | 0

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Answered
Mathworks Questions Resolved.
You should see a button next to the Answer allowing you to accept it. You can also Upvote the answer to award the answerer extra...

17 hours ago | 0

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Answered
Finish lines in the image
Here is another method based on interpolation, and faster than dilating with large strels. [m,n]=size(A); [I,J]=find(bwskel(...

19 hours ago | 0

Answered
Calling vectors from a user defined function?
You are missing a multiplication operator after the 2 in line 15.

1 day ago | 1

Answered
Steepest descent method algorithm
alpha is too big. Try alpha=0.001.

1 day ago | 1

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Answered
Image processing and sub-array summation
You can use sepblockfun from the File Exchange https://www.mathworks.com/matlabcentral/fileexchange/48089-separable-block-wise-...

1 day ago | 1

Answered
Finish lines in the image
Perhaps as follows, gapsize=36; A=imcrop(rgb2gray(imread('image.png'))); B=(imdilate(A,strel('sphere',ceil(gapsize...

1 day ago | 1

Answered
Optimization expression operation not supported
Maybe this is what you intended, C=cashFlows*bonds-obligations; E=C.'*triu(ones(8)); ALM.Constraints.Const1 = (E.*(1+Rates)')...

1 day ago | 0

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Answered
How to deblur an image after gauss filter and image registration?
Use imregtform to perform the registration on the blurred images and to obtain the optimal tform. Then apply the tform to your o...

2 days ago | 0

Answered
How to find the (x,y) combinations that make z=0?
You can use fimplicit https://www.mathworks.com/help/matlab/ref/fimplicit.html

3 days ago | 0

Answered
Plotting a for loop
C=nan(1,101); F=C; %preallocate for i = 0:100; C(i+1) = i; F(i+1) = (i*1.8)+32; end plot (C,F) xlabel(...

3 days ago | 0

Answered
fsolve with functions inside script
A=3; B=2; x0=1; fsolve(@(x)fun(A,B,x) ,x0); function F=fun(A,B,x) A=A; B=B; F=A+B/x end

3 days ago | 0

Answered
Find the cell index in a nested cell array, corresponding to a string (by using strcmp)
B=cellfun(@(x) strcmp(x, 'BLUE'), A, 'UniformOutput', false); cellfun(@(c) any(c(:)), B)

3 days ago | 1

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Answered
Remove rows in variable dimension
idx=repmat({':'},1,ndims(M)); idx{dim}=1:size(M,dim)-N; M2=M(idx{:})

3 days ago | 0

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Answered
How to set up the following optimisaiton witth quadprog?
You haven't shown any constraints. Are you sure you couldn't just use lscov? If you do have constraints, I think lsqlin would b...

3 days ago | 0

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Answered
Error using horzcat Dimensions of matrices being concatenated are not consistent.
I suspect it is because y is a column vector, whereas you intended it to be a row vector. You should run the code with "Pause on...

3 days ago | 0

Answered
object detection in a binary image
>> bwimage=imbinarize(rgb2gray(imread('bwimage.jpg'))); >> locations=regionprops('table',~bwimage,'Centroid') locations = ...

5 days ago | 0

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Answered
Main diagonal operations problem
x=eye(4); x(1:5:end)=0.7*rand(4,1)+0.3

6 days ago | 1

Answered
Unique rows of 2 cells with 2 columns each.
I tried the following 2 codes: unique(vertcat(IdxMembers,IdxMembers2),'rows')... I get the unique values in dim (nr. of unique v...

6 days ago | 0

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Answered
how to sort variable of an array?
sort(M,'descend')

6 days ago | 0

Answered
confront values in 2 matrix
min(A(1,:), B(1,:))

6 days ago | 2

Answered
Mean matrix of different size matrices in one cell array
cellfun( @(a)mean(a(:)) , A)

6 days ago | 0

Answered
upper and lower curves
You can use the quantile command https://www.mathworks.com/help/stats/quantile.html to determine the upper and lower quartiles...

6 days ago | 0

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Adjust regionprops orientation in order to get 360 degree value.
theta = 90-Orientation assuming theta increases clockwise.

6 days ago | 0

Answered
using lsqcurvefit with normalized error
This way I get a good fit but then I cannot plot the 95% confidence interval. fmincon doesn't return the Jacobian, but it does ...

7 days ago | 1

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Answered
fmincon is nonlinear constraints satisfied, then not satisfied when I include objective function
The algorithms of fmincon try only to satisfy the nonlinear and A,b,Aeq,beq constraints at convergence. They do not pledge to sa...

8 days ago | 0

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