Community Profile # Bruno Luong

Last seen: 1 day ago Active since 2009

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How to efficiently index into memory and call functions within for loops
When you index a hybrid slide (j positive integer scalar) % x = ... % j = ... xidx = x(:,:,:,j,:,:) (here I take a 6D array ...

3 days ago | 0

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is there a way to perform this task w/o using loops?
You might consider store in table instead NOTE: using table would be more convenient to access data, not necessary faster p.va...

4 days ago | 1

How can I stabilize the matrix left division (i.e. "\")?
Try pinv, lsqminnorm it can stabilize somewhat the inversion with (near) singular matrix. Both bave a tolerance argument to tune...

5 days ago | 0

square matrix containing Chebyshev polynomials becomes singular when its size becomes greater than a certain value
That is exactky what I have suggested in my answer: use the Chebyschev nodes t0 = 0; tf = 4; N = 75; syms x h = chebyshevT(...

5 days ago | 0

square matrix containing Chebyshev polynomials becomes singular when its size becomes greater than a certain value
If you select discrete points d the Chebychev nodes see definition wiki, and not uniform, it will become well posed.

6 days ago | 0

interpolate a 2D map (array) of density samples and preserve the total ?
Use trapz for the integration (not sum), it should match (up to round off) with linear interpolation and interger subsamping fo...

8 days ago | 0

Question

xlabel/ylabel 'HorizontalAlignment' issue
I don't understand the 'HorizontalAlignment' of the text labels. It is not centered (when the figure has different size than the...

8 days ago | 1 answer | 2

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Coefficents of piecewise polynomial in matlab
Similar answer as here points = [1 0 -1 0 1;0 1 0 -1 0]; pp = cscvn(points) m = pp.dim; p = pp.pieces; %D = diff(poi...

9 days ago | 0

cscvn of a function, coefficients and breaks
This is how to use pp m = 2; n = 5; % 25 in the original question points = rand(m,n); pp = cscvn(points) m = pp.dim; p =...

9 days ago | 0

How to index two vectors together
There is FEX, and fast if you have compiler and compile the mex file. https://www.mathworks.com/matlabcentral/fileexchange/2985...

9 days ago | 0

The difference between performing the fft2 and the convolution
Use this function, it will perform the convolution using fft method rightly https://www.mathworks.com/matlabcentral/fileexchang...

9 days ago | 0

How can I rotate the axes' labels parallel to the orientation of the axes?
Try this (the letters of label are rotated but the aspect ratio remain constant so they can be read easily but are not look like...

9 days ago | 0

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Compact way to calculate the centroid of a boundary of a set of points
@Sim The area of the polygonal (A in the book) is sum(A)/2 in Jan code. So sum(A)*3 in Jan's code is equal to 6*area. They are...

10 days ago | 0

Mex function Implementation for nested-functions
you did not include operation.c in mex command

10 days ago | 2

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Strange warning how to interpret it?
Fixed with update 4 https://www.mathworks.com/support/bugreports/3114312

12 days ago | 1

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Compute only a few entries of a big matrix product
It will not store the result in 2D matrix but 3D array. I hope you can switch to this format of storage. x=rand(10000,10); k =...

13 days ago | 0

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Matrix addition only to elements equal to zero
C=B; B0 = B==0; C(B0)=A(B0);

13 days ago | 0

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First look of your code shows that you do this mistake: https://www.mathworks.com/help/matlab/matlab_prog/preallocating-arrays....

16 days ago | 0

How to efficiently calculate a weighted sum of 3 dimensional matrix through a vector in matlab
This uses matrix multiplication so it should be well optimized and fast. [m,n] = size(A, [1 2]); C = reshape(A,m*n, []) * B(:)...

16 days ago | 2

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Matrix inverse in objective function
The inv() is not supported by optimization expression see https://www.mathworks.com/help/optim/ug/supported-operations-on-optimi...

16 days ago | 0

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Find all possible combinations of numbers with a specific array length
char(dec2base(0:4^12-1,4)+('A'-'0'))

16 days ago | 1

Order of code execution seems weird
%% Function in app.PlotSetup function printProcess(app, message) app.StatusEditField.BackgroundColor = app.yellow; app.Status...

17 days ago | 1

how to use plot to draw a minor arc in matlab without calculating the angle range?
% Generate A, B, C, C is the center and A B are two points on circle r = rand(); C = randn(2,1); phi1 = 2*pi*rand; A = C + r...

17 days ago | 1

Multipilication of N-dimension array
D = rand(3, 3, 3); rotm1 = rand(3, 3, 2); for num=1:size(rotm1,3) for i=1:size(D,3) res(:,:,i,num)=rotm1(:,:...

18 days ago | 1

Why does C{1}(1) work but C(1){1} results in an invalid array index error in MATLAB?
"I would like to understand the rationale behind MATLAB's requirement for parentheses indexing to appear last in an indexing exp...

21 days ago | 0

How can I produce this matrix?
m=6 n=3 j=randperm(m,n-1); A=accumarray([2:n;j]',1,[n,m]); A(1,setdiff(1:end,j))=1

22 days ago | 1

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Implicit expansion for griddedInterpolant

24 days ago | 0

Linking Matlab Libraries to Mingw for Another C++ Program
You need https://www.mathworks.com/products/matlab-compiler-sdk.html

26 days ago | 0

matrix value propagation along the rows
Any of these should do A = [1 2 3 4 5 6 7] B(1:19,1:7)=repmat(A,19,1) B(1:19,1:7)=repelem(A,19,1) B(1:19,1:7)=A(ones(1...

28 days ago | 0

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