# Bruno Luong

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**Content Feed**

How can I call M fuctions in different thread in mex coding matlab and C++?

No you cannot. MATLAB will crash since many MATLAB functions are not thread safe.

1 day ago | 0

| accepted

How to quickly do Cholesky factorization for many small matrices?

It requires MEX, but it should be fast https://www.mathworks.com/matlabcentral/fileexchange/37515-mmx

5 days ago | 0

how to vectorize squared function

X=rand(3,10); Y=rand(4,10); L=rand(10); N=size(X,1); M=size(Y,1); XX=reshape(X,N,1,[]); YY=reshape(Y,1,M,[]); YX=reshap...

6 days ago | 0

Question

Trigger event for graphic handle object?

The function notify seems to be designed for user-define class. Is it possible to make it works on MATLAB graphic handle objects...

9 days ago | 0 answers | 1

### 0

answersIs it possible to make inactive some of lines?

Put "..." (without the quotes) in front of the lines you want to hide

20 days ago | 0

Return all ShortestPath explored nodes

This problem has been answered in this thread https://www.mathworks.com/matlabcentral/answers/494497-how-can-i-get-all-the-exi...

21 days ago | 0

How interp2 deal with edges on bicubic interpolation?

The boundary handling is descriibed in the section Boundary Condition of this Cubic interpolation reference Especially the equa...

21 days ago | 2

| accepted

splines with derivative conditions at support points

There is the option point-wise constraints (pntcond) of my FEX BSFK to achieve your goal.

22 days ago | 0

how to use threads in matlab app designer

Many MATLAB stock functions are not thread safe, they are not suitable for multi-thread run. This is MATLAB limitation one canno...

29 days ago | 0

Compiler Support for Intel® oneAPI Toolkits - Fortran

It works for me (C) you light be abe to adapt for fortran https://www.mathworks.com/matlabcentral/answers/678588-mex-how-to-mod...

1 month ago | 0

How to generate random uint64 values

maxval = int64(2^60); n = 100; twop32 = 2^32; q = double(maxval/twop32); hi = floor(q*rand(1,n)); himax = floor(q); lom...

1 month ago | 0

How to generate random uint64 values

I can't see why you are reluctant to generate 2 x 4 bytes r = typecast(randi(intmax('uint32'),2*100,1,'uint32'),'uint64')

2 months ago | 1

Graph Laplacian and adjacency matrix

Not sure what data format you have, but for graph % TMW example s = [1 2 2 3 3 3 4 5 5 5 8 8 9]; t = [2 3 4 1 4 5 5 3 6 7 9 1...

2 months ago | 0

Best practices to use Matlab assert

No C debug mode slows every statement down. ASSERT costs the overhead of checking whatever you instruct MATLAB to check. It ma...

2 months ago | 0

Program to generate permutations in a certain order

clear X X{1}=[1 1 0 1]; X{2}=[1 0 1 0]; X{3}=[1 0 1 1]; X{4}=[1 1 1 0]; X{5}=[0 1 0 1]; X{6}=[0 0 0 1]; n=length(X); P...

2 months ago | 1

Equivalent of c++'s NULL or python' s None in MATLAB

If you use recent MATLAB you can use also missing and ismissing

2 months ago | 0

Question

How to change number precision with writestruct

The number of significant digits of writestruct is quite limited, as showed by this example s=struct('pi',pi); writestruct(s,...

3 months ago | 1 answer | 0

### 1

answerReplace nested loops with a matrix

i=2:nhx-1; j=2:nhy-1; U(i,j)= U(i,j)-dt*(Pc(i+1,j)-Pc(i-1,j))/(2*hx);

3 months ago | 1

| accepted

Get indices of all rows containing a value - repeated or not

[c,~,J] = unique(sort(connections,2),'rows'); [i,~,I] = unique(c); [~,j] = ismember(i, id); xy = [x(j) y(j)]; I = reshape(I,...

3 months ago | 0

| accepted

Is there a way to vectorise this vector/matrix product?

G = real(dot(W,R*W,1)).';

3 months ago | 0

Relative Ranking of position in an array

I10=[1 2 1 1 1 2 1 1 2 2 1 3 6 3 1 3 3 1 4 3 4 3 2 3 4 2 3 3 4 2 7 4 6 2 5 4 5 5 5 5 6 7 5 4 5 8 8 6 4 5 4 6 6 7 9 7 7 2 7...

3 months ago | 0

Optimize repeated permutation of a large vector

s = [1 2 3 4 5 6 7 8]; n=[4 3 1]; c=cumsum([0 n]); p=2:length(s)+1; p(c(2:end))=c(1:end-1)+1; s(p)

3 months ago | 0

Error using fwrite : Cannot write value: sparse arrays are unsupported.

[i,j,v] = find(S); then save i,j,v with fwrite

3 months ago | 0

| accepted

Optimize repeated permutation of a large vector

s = [1 2 3 4 5 6 7 8]; i=1:length(s); n=[4 3 1]; c=cumsum([1 n]); b=cumsum(ismember(i,c)); p=mod(i+1-c(b),n(b))+c(b) s(p...

3 months ago | 0

| accepted

find the position of all non-zero minimum values in each column of a matrix

a = [2 0 3;1 2 5;0 0 0;1 3 3;0 0 6;0 2 7;1 0 0] b=a; b(b==0)=NaN; [r,c]=find(b==min(b,[],1)); rmin=accumarray(c(:),r(:),[siz...

3 months ago | 1

Turn logical matrix into string vector

Assuming idx has one 1 per row idx = logical([0 1 0; 0 0 1; 1 0 0; 1 0 0; 0 1 0]); vec = ["A","B","C"]; [r,c]=find(idx); r...

3 months ago | 1

Symetric matrix power optimization

Youeu can edit MATLAB function mpower.m and try to the basic calculation (line 76 in my case) D = D*D; % I assume p is integer...

3 months ago | 0

| accepted

How can I avoid loop for code optimization?

Use MultipleQR FEX (C compiler for MEX build is required, unless for Windows platform) y = linspace(1,10,1000); Y = reshape(...

3 months ago | 1