# Bruno Luong

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**Content Feed**

How to know interpolated points in a MATLAB plot?

hl = findobj(gca, '-depth', 1, 'type', 'line'); x=get(hl,'xdata'); y=get(hl,'ydata'); y10 = 10; i = find((y(1:end-1)-y10...

2 hours ago | 0

minimum value optimization of matrix with constraints

Straighforward implementation, it seems more reliable than Matt's square-root parametrization. The square-root makes the gradie...

5 days ago | 0

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The most efficient way to calculate multiplication and summation of two large matrices

It is just a scaling of matrix multiplication, if you haven't recorgnize it A=rand(300,1000); B=rand(300,1000); tic C1=(A*...

9 days ago | 1

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Create random symmetric matrix with given cond number to pass it to pcg

n=10; % size of the system condtarget = 1000; % generate ransom spd matrix [Q,~]=qr(randn(n)); r = rand(n,1); r = (r-min(...

9 days ago | 0

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How to get a smooth plot by filtering the sudden variation of the data?

It recovers a big tail part of the signal. Hard to guess what should be the signal at the begining. A=readmatrix('https://www.m...

9 days ago | 0

FFT analysis with window of vibration during milling

I don't see the need of calling sgolayfilt. It is just a linear filter so it is equivalent to scale down the signal in frequency...

10 days ago | 0

natural cubic spline interpolation of y-values: how to get derivative of the spline wrt the y-values?

The derivative f wrt to y_i is the spline interpolate b_i := (0,0,...,1,0...) where 1 is at ith position, since the spline is li...

12 days ago | 0

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natural cubic spline interpolation of y-values: how to get derivative of the spline wrt the y-values?

In this thread https://fr.mathworks.com/matlabcentral/answers/1894800-how-to-remove-noise-from-curves-and-take-their-derivates?s...

12 days ago | 0

How to use isoutlier based in a part of the data?

Not sure, you are not better to describe what you want than most people; what you cann outlier seems to be point that violate th...

12 days ago | 0

Modified Akima Interpolation process

Just look at the refernce provided in the doc page A New Method of Interpolation and Smooth Curve Fitting Based on Local Proced...

14 days ago | 0

How to get around sparse row deletion for least squares calculation

I'm nit sure why you formalize as block sparse, since it is like solving d independent linear systems of the same size, and can ...

14 days ago | 0

Question

factorization of Multivariate polynomial

Hello, I want to factorize a multivariate polynomial in a complex field. I just don't understand why the result of this simple p...

14 days ago | 2 answers | 0

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answerswhat is a reasonable step tolerance for optimization algorithms if parameters are in the range [0,1]?

Your question is not clear enough. the official doc explains how it eaxctly works https://www.mathworks.com/help/optim/ug/toler...

18 days ago | 0

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Matrix multiplication gives different result than manual dot products with each column

"Does anyone know why these two expressions don't give the same answer? " Why should they? The algorithm can perform diffrent s...

18 days ago | 0

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Why do I see a drop in the last datapoint (Nyquist frequency) of the spectra derived from pwelch?

No I beg to differ the answers that have given to you. The reason is the convention of onesided spectrum. In the code computepsd...

19 days ago | 0

Why the function like (1 - cosd(x)) / cosd(x) doesn't create an vector and can't plot?

Change / to ./, the "/" is matrix left-division and does something you won't expect for vectors x=-25:0.1:25; %Grad in Bogenma...

19 days ago | 0

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Failure to load structures into an array through a loop

I copy my answer fromthis thread Usage is typically like this: cellresult = cell(1,n) for i=1:n % do something first ...

19 days ago | 0

Finding two similar Matrix in a whole set

If you have great number of matrices (like 1000 or more) reduce the number of comparisons by computing for each matrix the min, ...

19 days ago | 1

access matlab figures by opening them with a mouse while a matlab terminal application is still running

Here is one way of calling dbcont to exit debug mode without user typing it this FEX keyboard ... wait until user do his/her s...

20 days ago | 1

Sorting random x,y spots on circularly closed line in order to calculate properly the perimeter and the area of the polygonal shape.

Formulate as TSP and solve with intlinprog as showed here

21 days ago | 1

How can i transform rad/s to hertz for graph?

omega = 2*pi*f with unit omega [rad/s] f [1/s]

23 days ago | 0

How do I uninstall an older version of MATLAB after I have installed a newer version on my Mac OSX?

No don't disactivate MATLAB, just uninstall 2019b. Activation is common for all installed versions. Many versions can be inst...

24 days ago | 2

Question

What is MCR R2022b Update 5 ?

When I try to download MCR 2022b, it appears the Update is 5 https://ssd.mathworks.com/supportfiles/downloads/R2022b/Release/5/...

25 days ago | 2 answers | 0

### 2

answersR2022B Update4 is not offered

The online update for R2022b Update 4 is NOT offered by TMW. Workaround : do the offline installation. Risk: you need to unin...

25 days ago | 0

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Are there any matrix balancing/scaling function in matab for complex rectagular matrices?

Check out normalize

26 days ago | 0

Question

R2022B Update4 is not offered

Is it just me or the update 4 is not offered via the menu Help => Check for Updates I'm using Update 3

26 days ago | 5 answers | 0

### 5

answersFinding the length of the longest continuous streak of a same number for each row of a matrix

p = 3; q = 10; r = 2; A = sort(randi(10,p,q,r,'uint16'),2) B = reshape(permute(A,[2 1 3]),q,[]); t = true(1,width(B)); [...

29 days ago | 1

| accepted

Is this a mistake in documentation or my misunderstanding of FFT?

"Single sided Amplitude spectrum from Double sided spectrum it is only the DC component to be excluded from multiplying by 2" N...

1 month ago | 0

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How to encrypt compilation files for standalone?

The MATLAB source files are already encrypted (with you compile with MATLAB compiler, MCC)

2 months ago | 1

movavg with custom type and weights

movavg requires first array is a column vector or matrix A = 1:5; B = [0.5 0.5]; movavg(A(:), "custom", B) % or reshape back...

2 months ago | 2