Community Profile # Matt J

Last seen: Today 2009 이후 활성

Professional Interests: medical image processing, optimization algorithms

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How to plot three X & Y sets of points on the one graph from a text file
plot( Ifile(:,[2,4,6]) , Ifile(:,[3,5,7]) )

약 5시간 전 | 0

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How can I separate a sorted array into multiple at points referenced by another array?
This might be what you want: A = [1 4 7 9]; B = [1 2 3 4 5 6 7 8 9 10 11 12 13]; G=discretize(B,[A,inf]); C=splitapply(@...

약 6시간 전 | 0

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How can one reshape this table?
Perhaps as follows? load tst T [Gage,IDage]=findgroups(T(:,1)); [Gdate,IDdate]=findgroups(T(:,2)); Tnew=[ IDdate, a...

약 7시간 전 | 0

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Getting different results from function handle & syms for a same equation. How to avoid it?
The results are different because the polynomial coefficients are different: >> sym2poly(P)-coeffs' ans = 1.0e-04 * ...

약 13시간 전 | 0

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How to "quicksave" a file in app designer?
The 3rd argument to uiputfile should end with a path separation character: [file,path] = uiputfile(".mat","Save AnimTronics Sys...

약 13시간 전 | 0

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how convert the vector to matrix ? unknown number of columns
No, the solution is ill-defined. Another result with the same number of rows is: A=[1 2 3 4 5 6 7 8 9]

약 22시간 전 | 0

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Applying vectorization techniques to speedup the performance of dividing a 3D matrix by a 2D matrix
Another idea. clc; clear all; % Test Data % I'm trying to remove the for loop for j in the code below N = 10; M = 10; Nx...

1일 전 | 1

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Applying vectorization techniques to speedup the performance of dividing a 3D matrix by a 2D matrix
On the GPU (i.e. if A and b are gpuArrays), the for-loop can be removed: Uhat = permute( pagefun(@mldivide,A,reshape(b,[],1,Nx)...

2일 전 | 0

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Finding the vertical offset of a gaussian fit
This File Exchange routine does gaussian+constant fitting: https://www.mathworks.com/matlabcentral/fileexchange/69116-gaussfitn...

2일 전 | 0

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How to set a custom equation to fit 5 points in space by fitsurface?
I can't find "fitsurface" in the Mathworks documentation, but the fit is easy enough to do algebraically. x=x(:); y=y(:); z=z(:...

2일 전 | 0

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Why is x(:) so much slower than reshape(x,N,1) with complex arrays?
The following simple test seems to support @Bruno Luong's conjecture that (:) results in data copying. The data of B1 resulting ...

2일 전 | 1

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Is it possible to correctly perform a multi-dimensional FFT on a 1D linearised version of a 3D array?
Reshaping to and from 3D format should not add significant cost: Nx = 256; Ny = 256; Nz = 128; N = Nx*Ny*Nz; A0 = rand(N,1)...

3일 전 | 0

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질문

Why is x(:) so much slower than reshape(x,N,1) with complex arrays?
The two for loops below differ only in the flattening operation used to obtain A_1D . Why is the run time so much worse with A_3...

3일 전 | 답변 수: 3 | 2

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see the 3d image and see the coordinates while moving the mouse over the image
You can use imshow() to display any particular slice of the image and then use the axis datatip button to get the in-slice 2D co...

4일 전 | 0

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How do i find the coordinates of a boundary
How about simply, [m,n]=size(Image); I=boundary(:,1); J=boundary(:,2); corner1 = [1, max(J(I==1))]; %row/column coordinat...

4일 전 | 0

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How to Draw an ellipsoid between two 3d coordinates
Another way would be to use the ellipsoidalFit.groundTruth method in this File Exchange submission. https://www.mathworks.com/m...

4일 전 | 0

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Trying to count the number of pixels in an image over a specific RBG value
results.area=nnz(imstd>90);

4일 전 | 0

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Normally distributed random numbers with fixed sum
Why not simply, x(1:N-1)=randn(1,N-1); x(N)=fixedValue-sum(x(1:N-1))

4일 전 | 0

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Only analyze what is outlined in black in an image
If you have a binary mask of the circles, you can just do numBlack = nnz( circles & ~BW ); numWhite = nnz( circles & BW);

4일 전 | 0

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If the quadprog problem is infeasible, how i can solve it with a certain tolerance?
It never really makes sense to have more equality constraints (here 36) than you do unknowns ( here 6). In order for the problem...

6일 전 | 0

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How to construct a "ones" matrix with zero blocks in the diagonal
repelem(1-eye(4),4,4)

7일 전 | 1

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Iterative solution of non-linear equation with a provided guess value?
You could use fzero's OutputFcn option https://www.mathworks.com/help/optim/ug/fzero.html#btn3z5s-options to access the sequen...

7일 전 | 0

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Iterative solution of non-linear equation with a provided guess value?
Using fsolve() instead of fzero(), you could solve the problem as a system of two equations in two unknowns. The two unknowns ar...

7일 전 | 0

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Failure in initial user-supplied nonlinear constraint function evaluation
One problem: nonlcon = @simple_constraint; There is no function called 'simple_constraint' in your attached script. There is a...

7일 전 | 1

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for loop for permutations of for length of array
List=nchoosek([a,b,c],2); for i=1:size(List,1) p1=List(i,1); p2=List(i,2); ... end

8일 전 | 1

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2*2 Matrix factorization/decomposition
I also found out what I wanted may have something to do with PLU(permuted lower upper decomposition), but am clueless to how to ...

8일 전 | 0

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How can I call a script within a for loop, looping over multiple files?
result = scriptname(ID{nSubject},Visit{nVisit});

9일 전 | 0

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I am trying to find the exact distance of a curvy line.
Why not as follows? I2 = imread('image.jpeg'); blue=bwareafilt( I2(:,:,1)<=50 & I2(:,:,2)<=50 & I2(:,:,3)>=200, 1); Len...

9일 전 | 0

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Number of branches per branch point
Perhaps as follows: k=ones(3); k(5)=0; neighborCount=conv2(double(BW),k,'same'); neighborCount=neighborCount.*(neighborCo...

9일 전 | 0

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