Bruno Luong

Last seen: Today | Active since 2009

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How to find the closest value pair in a matrix?
For A that has at least 3 rows and the closest in the sense of l2 norm (auclidian distance), without the need of toolbox. But i...

14 hours ago | 0

Answered
How to vectorize the multiple loops
Warning code not tested for correctness: EDIT correctness is now check % set up the initialization params a_b = 4;% max 8 h ...

1 day ago | 0

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How can I obtain all possible combinations of 3 decimals whose sum equals 1, without running into memory and space issues?
Use my FEX https://www.mathworks.com/matlabcentral/fileexchange/17818-all-permutations-of-integers-with-sum-criteria The array ...

3 days ago | 1

Answered
Memory problems with Cell Array mex file
Another potential issue is your cell does not contain double as assumed. In this case double* ptr = mxGetPr(cell); and later...

3 days ago | 0

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Answered
Difference between 2 orientations
I recall a long discussion with Roger, James on this topic on the newsgroup long time ago. At the time our conclusion is quate...

6 days ago | 0

Answered
A faster union of polyshapes
using union of polyshape, just different order WARNING: code not fully tested and NOT commented not fully optimized. But it loo...

6 days ago | 1

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Answered
How to select, or filter, the external border/boundary in a set of (x,y)-points? [Part 2]
Use the right tool: polyshape class load('borders2.mat') n = length(a); warning('off','MATLAB:polyshape:repairedBySimplify'...

6 days ago | 3

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Answered
How to solve the matrix P in the Lyapunov equation "A'P+PA=- Q" in Simulink
I don't know simulink nor lyap function but just to tell you you can solve with standard algebra, so I hope it could be incorpor...

6 days ago | 0

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Why is it so fast to calculate one-dimensional cubic Spline interpolation through matlab?
"I learned that the Time complexity of one-dimensional cubic Spline interpolation is at least n ^ 2" What is n? There is two d...

6 days ago | 0

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Answered
Calculate the average of each matrix block
A = [1 2 3 4 1 2 3 4 1 2 3 4 7 6 5 4 ; 1 2 3 4 1 2 3 4 1 2 3 4 7 6 5 4 ; 1 2 3 4 1 2 3 4 1 2 3 4 7 6 5 4 ; 1 2 3 ...

7 days ago | 0

Answered
How to programmatically determine the default number of workers set in parallel preferences
Please see if this thread can help you

7 days ago | 0

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Generate a pseudo-random sequence of numbers with restrictions
Try this succeed = false; while ~succeed c = repelem(25,1,4); n = sum(c); r = zeros(1,n); for i=1:n ...

7 days ago | 1

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Answered
Memory efficient alternative for meshgrid?
Compute with auto-expansion capability after reshapeing vectors in appropriate dimensions rather than meshgrid/ndgrid % [a,b,c]...

9 days ago | 0

Answered
Attempt to grow array along ambiguous dimension.
Replace the problematic line of code with handGesture(repmat(~binaryFrame,1,1,size(handGesture,3))) = 0;

10 days ago | 0

Answered
unable to install MATLAB R2023a on windows 11
MATLAB_Runtime_R2023a_Update_3_win64 is not MATLAB, it's a runtime used by program built with MATLAB compiler. It's normal tha...

10 days ago | 1

Answered
Finding Indices of Zeroes Following Non-Zero Elements in MATLAB
seq = [0,0,0,0,0,0,1,3,5,2,4,6,7,8,3,0,0,0,0,4,1,10,22,11,22,44,44,12,0,0,0,0] b = seq ~= 0; union(findstr(b, [0 1]), findstr(...

11 days ago | 0

Answered
Is there a way to start indexing with 0 in MATLAB?
One way is to define your onw class with overloading subsref and subsasg https://www.mathworks.com/help/matlab/matlab_oop/code-...

15 days ago | 0

Answered
Least squares linear regression with constraints
"This is a non-linear problem of course, but I do linearize it by taking log on both side" That's the problem. When you transfo...

18 days ago | 0

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how to solve diagonal matrix of each page of a 3D vector ? pagediag?
[~,n,p] = size(A); [J,K] = ndgrid(1:n,1:p); B = accumarray([J(:) J(:) K(:)], A(:), [n,n,p]);

20 days ago | 0

Answered
Meshgrid to be used for hexagons
If you need coordinates and no connectivity graph, the code can be simplified, you can use meshgrid if you wish to MATLAB autoex...

20 days ago | 0

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Meshgrid to be used for hexagons
Code from this thread. Not sure why you must use meshgrid https://www.mathworks.com/matlabcentral/answers/642930-adjacency-matr...

20 days ago | 1

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What is the mathematical principle of two-dimensional cubic Spline interpolation ?
The 2D spline is tensorial of 1D splines, meaning it makes 1D is x, then 1D in y. If you do the other way around it give the sam...

21 days ago | 0

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Answered
Inverse of sorting arrangement
If A has distinct elements such as A = rand(1,10) a single line command is [B,~,J] = unique(A); Check J B(J)

21 days ago | 2

Answered
~exist(xxx) in IF condition not working
You have a FILE or FOLDER named "data" on some of your computers, not on other exists chech existing for file and folder as wel...

24 days ago | 0

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May I ask if there are any good methods in MATLAB that can fit broken lines
Use my FEX BSFK xyz=readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1417239/zx.txt') xyz0 = mean(...

26 days ago | 0

Answered
For loop over permutations of 1:n with very large n
If you don't care about finding optimal solution, why not just do n = 1e15; % 1e18 has problem of coding as in my comment above...

3 months ago | 0

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find rows in a matrix where all the elements (of those rows) are not NaN
An alternative ways of testing a = [ NaN NaN NaN NaN NaN NaN NaN NaN NaN...

3 months ago | 0

Answered
Inverse wavelet transform using only one wavelet transform
I guess because you feed in random data, the scale cannot by estimate correctly therefore the first level of the scale (and also...

4 months ago | 0

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try...catch for memory full error in imaq toolbox ?
To my knowledge there is no simple way to detect memory issue. What you ask MATLAB, e.g., using command such as [~,sys] = memo...

4 months ago | 0

Answered
What could be a faster way to calculate first derivative of a field?
dfdt = (f(3:end)-f(1:end-2))*(1/(2*dt))

4 months ago | 0

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