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# Bruno Luong

Last seen: Today Active since 2009

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mldivide (backslash): advantage by using sparse matrix instead of a full matrix with respect to the quality of the results?
If your condition is 3.65e27 you wi=on't get any reliable solution regardless the method. The full matrix use QR with permutati...

9 days ago | 3

histc vs. histcouns
The result differ by the way the last bin is handed in both function. To get the same result you must change the last edge to In...

10 days ago | 0

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2×2 matrix
c=cell(2*2,1); [c{:}]=ndgrid(1:8); a=reshape(cat(5,c{:}),[],2,2); a=permute(a,[2 3 1]); disp(a)

30 days ago | 0

Cholesky factorization: How to change code to produce A = L' * D * L instead of A = L * D * L' .
% Generate random symetric A A=randn(5); A=A'+A; disp(A) [L,D]=ldl(A); disp(L*D*L') [L,D]=ldl(rot90(A,2)); L=rot90(L,2)...

1 month ago | 0

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Finding face vertices of a polygon
If you have R2021a or later, there is a new method allcycles that can achieve the goal N = [... 5 12 5 11 6 8 ...

2 months ago | 0

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How to return a uint64_t from a mex function?
https://www.mathworks.com/help/matlab/apiref/mxcreatenumericmatrix.html mxArray *A; A = mxCreateNumericMatrix(1, 1, mxUINT64_C...

2 months ago | 1

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How exactly does MATLAB calculate a sum of array elements by its sum() function? Does it use any compensated summation algorithm such as Kahan?
According to my test it seems MATLAB does not sum by chunk when operating on vector, to ensure the result is consistent, i.e. no...

2 months ago | 0

how can I use mexw32 files on my 64-bit matlab?
You cannot.

3 months ago | 0

why evalin doesnt wotk in App Designer matlab 2017b?
You probably forget to populate APP_isc_n_gbxInp in the base workspace. I create a small app (attached) and evalin works just f...

3 months ago | 0

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Error using mex No supported compiler was found.

3 months ago | 0

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Has QR [Q,R,E]=qr(X,0) changed? licols for extracting lin indep cols is not working
It seems working fine on random matrix (R2021b online server or my PC) X=randn(1000); [q,r,e] = qr(X,0); issorted(abs(diag(r)...

3 months ago | 0

How can I perform large sparse matrix multiplication efficiently when one sparse matrix is block diagonal?
You might rethink of the storage of your data, such as this (tic/toc result obtained from run on TMW online server): I=1e4; J=...

3 months ago | 1

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What is missing from MATLAB #2 - the next decade edition
Probably it breaks compatibility, but it would make functions/operators svd, *, ', .' dealing with n-d arrays similar to pagesvd...

3 months ago | 1

Run two scripts simultaneously matlab
Somewhat possible with parfeval But I would agree with Jan, runing two Matlab sessions is perhaps easiest.

3 months ago | 1

c++ programming.
In C++ the main function signature should be int main() The void argument is for C (not C++). Your code has illegal comma ","...

3 months ago | 1

Unexpected, unexplained, difference between Matrix linear index and row and column subscripts
Try to change for i=size(P,1)*size(P,2) to for i=1:size(P,1)*size(P,2) You light also learn to use debugger so such task.

3 months ago | 1

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How to compute cholesky to all slice of a tensor?
For real semi definite matrices, you can take a look at https://www.mathworks.com/matlabcentral/fileexchange/37515-mmx Unfortun...

3 months ago | 0

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How do I swap 2 rows of a cell array?
C([2 3],:) = C([3 2],:);

3 months ago | 0

how to find the nearest value?
A=[ 1 2 3 4 5 6] B=[6.1 5.1 4.1 3.1 2.1 1.1] position_A=[10 20 30 40 50 60] loc = interp1(A,1:length(A),B,'nearest'...

3 months ago | 0

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I have matrix A and I need to find (e^(At)) where t is the sampling time. How to find that? Also what is the difference between exp(A) and expm(A)?
Math notation e^(At) is computed in MATLAB with expm(A*t) or equivalently expm(A)^t

3 months ago | 0

When the error comes, how to return a flag but not stop the process
You might learn about try / catch

3 months ago | 0

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Generate all possible combinations summing up to a given number
You can use this file exchange https://www.mathworks.com/matlabcentral/fileexchange/17818-all-permutations-of-integers-with-sum...

3 months ago | 0

Speed up comparing two arrays and write into new array
For simplification I use numerical data for Colors_Res/Assoc_Colors adatp tou your data type clear % Dummy test data coordInd...

3 months ago | 0

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How to strrep only certain strings
x = {'e-.00085';'8.5e-4'} regexprep(x, '^e', '')

3 months ago | 0

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MatlabR2019b standalone sharing
You need to have MATLAB compiler and they need to install the MCR.

3 months ago | 0

how to kill a process from Matlab
I don't know if it is matter but I always use PID to kill a process, not directly the image name. Here is my code function Kill...

3 months ago | 0

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Determine Camber and Thickness of a Airfoil - Given the xy coordinates
If you can tolerate some finite precision, you migh discretize the interior as b&w image, look for the skeleton https://www.mat...

4 months ago | 0

Problem in using scatteredInterpolant
Use nearest method F = scatteredInterpolant(..., 'nearest')

4 months ago | 0

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