# Bruno Luong

Last seen: Today 自 2009 起处于活动状态

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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...

12 hours 前 | 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:...

7 days 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 0

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

5 months 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 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 前 | 0

Effficient Computation of Matrix Gradient
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 前 | 0

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Effficient Computation of Matrix Gradient
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 前 | 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 前 | 1

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Function matchpairs does not work in MATLAB R2023a when I use a sparse cost matrix. Please help me out ASAP!
Your sparse matrix filled default cost wit 0 not 99. Then your expectation on that the result is identocal for different cost ma...

5 months 前 | 0

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error using spline: The first input must contain unique values.
Your spline command wouldn't do what you want, since for every x you have made corresponding two y values. It is NOT a function ...

5 months 前 | 0

error using spline: The first input must contain unique values.
You did not post your spline command, my guess is you do spline(x,y) Try to remove the last (or the first value of th, then do ...

5 months 前 | 0