Community Profile # Matt J

Last seen: Today Active since 2009

Professional Interests: medical image processing, optimization algorithms

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How to update constraint in nonlinear optimization
Divide into 3 sub-problems. Solve with the constraints (1) y<=20 and NLcon (2) 20<=x<=40, y<=20, and NLcon (3) y>=20 and NLco...

1 dag ago | 0

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Im trying to run fsolve inside a for loop but it seem that my second iteration inside the for loop is not able to read the initial trial point
Should the division be by Afull(i)? F = @(GG)[slopeACdisp(i)-((GG(2)-Cdispy)/(GG(1)-Cdispx(i))); -tau+(0.5*abs((G...

1 dag ago | 0

Accessing (interpolating?) data in 3D array
You could use griddedInterpolant() array=rand(290,480,90); F=griddedInterpolant(array); extract=F({linspace(4,8,10), 400:...

2 dagen ago | 0

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Problem with parfor with two variables
Do you need to see the toc output in real time? If not, just save it until later: %% My code Y_1 =nan(N,numel(alpha),numel(bet...

3 dagen ago | 0

Converting Structure into 3d Matrix
Matrix=cat(3, all_frames.Frame); However, you will need generous RAM. Your all_frames structure already consumes about 5 GB in...

3 dagen ago | 0

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Optimization Problem but don't have closed form expression
The problem is that I dont have a closed form expression for B_k in terms of μ_k. if I have a set of values for μ_k to get the c...

3 dagen ago | 0

how to generate integer sequence number by logistic map?
function [z] =logistic(r,N) %sequence is chaotic where 3.57 < r < 4. %r = 3.8; % r parameter for chaotic regime %size ; % siz...

3 dagen ago | 1

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circle inside triangle tangent points
You can find the circle using incircle in this FEX submission https://www.mathworks.com/matlabcentral/fileexchange/34767-a-suit...

4 dagen ago | 0

fmincon gets very slow after few time
A few more performance optimizations that you should consider: maps = zeros(rows,columns,3,'single'); %<------ post conversio...

4 dagen ago | 1

fmincon gets very slow after few time
I suspect samsid() is just not as smooth or well-conditioned as mse() for some pixels, and therefore takes more iterations to te...

4 dagen ago | 0

Question

Restore toolbar buttons to app after migration from GUIDE
After using the Guide-to-AppDesigner migration tool, my app no longer has the standard figure toolbar buttons in the app figure ...

4 dagen ago | 0 answers | 0

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Finding intersection points in a square.
Yes, you can use, https://www.mathworks.com/matlabcentral/fileexchange/93470-intersections-of-multiple-2d-lines-or-line-segment...

5 dagen ago | 0

Trying to understand behavior of holes in alphaShapes.
I found the following in posted material for a course at Stanford. It's a pretty intuitive explanation of how alpha shapes work,...

5 dagen ago | 0

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Function to compute product of all numbers from 1 to n
integerproduct(5) function r = integerproduct (n) if n==1, r=1; return; end r=n*integerproduct(n-1); end

5 dagen ago | 0

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Replacing Negative Values in Table with Previous Value in Column
T(:, {'D', 'E'}) = num2cell( fillmissing([D,E], 'previous') );

5 dagen ago | 0

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How do I create a 2D mesh of triangular elements?
Yes. Or triplot().

5 dagen ago | 0

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How do I turn off predictive text?
I've changed the Automatic Completion preferences, but it's still there. There is a different Automatic Completion section for...

6 dagen ago | 1

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How to concatenate output of objective function for lsqcurvefit?
c0 = [ic_arg{1}(x).'; ic_arg{2}(x).'; ic_arg{3}(x).'];

6 dagen ago | 0

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Saving outputs of a funtion inside nested for loop in organized fashion
Instead of returning 20 separate outputs, you could have paramA return them as fields of a struct. Then you could save each outp...

6 dagen ago | 0

Using bsxfun to plot
Now idea why you think bsxfun should be involved. Why not just, t=linspace(-2,2,n); plot(t,signal,t,filtsig)

6 dagen ago | 0

is there a function that receives 3 coordinates in X-Y as a matrix and calculates its Area and environment ?
p=polyshape(yourPoints); area(p) perimeter(p) centroid(p)

6 dagen ago | 1

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Remove duplicate points by Uniquetol
uniquetol(xy, 1, 'ByRows', true,'DataScale',[1,1]) % or

6 dagen ago | 0

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Submitted

Further tools for analyzing objects in N-dimensional images
A collection of tools to supplement bwpropfilt, bwareaopen, and the like.

Solving a large number (thousands) of different "Ax=b" equations when the matrices A are all the same small size (3x3 to 6x6), but different numbers.
If you have the Parallel Computing Toolbox, you can use pagefun(@mldivide,A,b) https://www.mathworks.com/help/parallel-comput...

6 dagen ago | 0

Solving a large number (thousands) of different "Ax=b" equations when the matrices A are all the same small size (3x3 to 6x6), but different numbers.
I suspect that a for loop will be fastest, but you could also try combining them into a single set of equations using, A=blkdia...

6 dagen ago | 0

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For loop with 2 variables
parfor k =1:N^2 [i,j]=ind2sub([N,N],k); .... end

7 dagen ago | 0

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Fminsearch curve fitting does not fit properly
Plotting your function in an interval around bmin shows that it is a minimum of the function you've provided. So, fminsearch did...

7 dagen ago | 0

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Question

Trying to understand behavior of holes in alphaShapes.
I have created the attached alphaShape object, which contains a hole. load alph_shape; shp plot(shp) I am trying to unders...

7 dagen ago | 2 answers | 0