# Bruno Luong

Last seen: Today Active since 2009

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Chasing what is wrong with 'dual-simplex-highs' in linprog
I try to see why 'dual-simplex-highs' algorithm fails and 'dual-simplex-legacy' works OK on this specific LP problem of size 46...

4 hours ago | 2 answers | 1

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Best computer specifications for fast Matlab numerical simulations/integrations?
The bench command in R2024a rates intel i9-12900 CPU on Windows 11 and Mac M2 best for ODE IMO the intel processor get hot easi...

1 day ago | 1

I substracted two 3D matrix and get a 2D matrix instead of 3D matrix, why?
You need to put 3 indexes in 3d array. If you put 2 it reshape your array to 2D. The correct command is probably dp=minus(p(1:...

8 days ago | 0

Scatteredinterpolant (linear) from symmetric data does not produce symmetric isolines
scatteredinterpolant all methods is based on triangulation of the data points. Even the data points are symmetric, the triangula...

2 months ago | 0

Intersection condition between two ellipses
Use FSOLVE to find numerical solution. Only xaimum one can be found c1 = [0; 5]; % circle center #1 c2 = [-5; 2]; % circle c...

2 months ago | 0

Intersection condition between two ellipses
Here is a solution for generic ellipses using FEX file here % Ti and ci define two ellipses E1 and E2 of the form % (x,y) st n...

2 months ago | 0

find a zero of a two-variable function
If you are not unlucky Trajectory = @(x) sum(x.^2,2)-34^2-1; % Test function, use use rather own X0 = [9.609 , 32.288]; %ini...

5 months ago | 0

call function name in the same function
This returns the name of the function being executed s = dbstack; funname = s(1).name; In recent MATLAB versions you can do i...

5 months ago | 1

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pinv operation in matlab
NOTE: This code is useful fonly or users who run version greater than R2021a and before R2024a, where pagesvd is supported by pa...

5 months ago | 0

How to do 3D matrix multiplication
A = rand(56,32,10); B = rand(32,32,10); C = pagemtimes(A,B); size(C)

5 months ago | 0

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Create an array of distinct objects of handle class
Why not simply calling the constructor as many time as you need arrDir = arrayfun(@(~)uilabel, 1:2); arrDir(1).Text = "textDir...

5 months ago | 0

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How to flip the x axis in a 3d plot?
Do set(gca,'XDir','reverse') one the surfc command is carried out s = peaks'; subplot(1,2,1) surfc(s) xlabel('x') subplot(1...

5 months ago | 0

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Extracting multiple signal segments without a for loop
As you like but this code is perhaps slower than the for-loop signal = rand(1000,1); segmentOnsetIndices = [50 120 550 600 750...

5 months ago | 1

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How to have individual numbers combine into a larger number
One way: UserIput = [1 2 3 10 11]; %% Coding X = polyval(UserIput, 16); X % Combine number clear UserIput % forget the ...

5 months ago | 0

Problem with solve() and "Empty sym: 0-by-1".
Your equations look illposed to me for three reasons* For a given j, LHS are known (4 x 1) vector Ax*Ax*B(:,j), let's call ...

5 months ago | 0

Efficient Vectorization of For Loop
Not tested but the sign reading tell me M = 2*B' * (A.*C);

5 months ago | 1

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uicontrol doesn't work in Matlab 2023a
The button position you give is way off push the button outside the universe. This happens with all MATLAB. figure;pauseButton=...

5 months ago | 0

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Finding the index k of square nilpotent matrix A
This modified version of binary search only use matrix multiplication and keep track of A^2^p, p = 0,1,2 ...The number of matrix...

5 months ago | 0

Finding the index k of square nilpotent matrix A
I modify your original code and now it seems working: function k = nilIndex(A) [n,n]=size(A); l=0; k=n; B =A^l; while k-l>...

5 months ago | 0

When Should Generalized eig() Solver be Used for Ordinary eig() Problems?
Actually I think eig with 2 inputs is more approprite for multiple order eigen value and the degenerate case to non trivial jord...

5 months ago | 0

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uniform knot vector for splines
Your knot sequence seems NOT to be suitable for interpolation. The interpolation matrix is singular. x = linspace(1,6,6); xi =...

5 months ago | 0

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Strange behavior with ODE45 dependent on tspan
I would divide the time interval in three parts, as the typical time scales are different during the pulse and outside the pulse...

5 months ago | 0

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Matrix multiplication not returning on certain matrix content (Intel)
The matrix contains many non normalized floating point numbers and operations on these numbers are very slow; >> load('C:\Users...

5 months ago | 0

Using fmincon to solve objective function in integral form.
trapz(tspan/length(t), 2*x.^2 + 2*xd.^2) This looks wrong to me, you seem to assume t is equi distance (even in that case you s...

5 months ago | 1

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Lognormal distribution parameters mu and sigma
Is mu=log(mean) and sigma=log(Standard deviation)? No: https://en.wikipedia.org/wiki/Log-normal_distribution If X is log-norma...

5 months ago | 0

The best N = 200; % 750 gradX_1 = zeros(N,N); w = rand(N,N); AXB = rand(N,N)+1i*rand(N); A = rand(N,N)+1i*rand(N); B = ran...

5 months ago | 0

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I propose this, and time testing for N = 200; N = 200; % 750 gradX_1 = zeros(N,N); w = rand(N,N); AXB = rand(N,N)+1i*rand(N)...

5 months ago | 0

fmincon solution does not differ from initial guess if I provide gradient
To get more info turn the option 'CheckGradients' to 'on', and check the exitflag (third output) of fmincon

5 months ago | 1

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