Community Profile

# Bruno Luong

Last seen: Today Aktiv seit 2009

#### Statistics

All

Abzeichen anzeigen

#### Content Feed

Anzeigen nach

Beantwortet
Merging piecewise polynomial (pp) structures
Using BSFK from this FEX https://www.mathworks.com/matlabcentral/answers/1810010-free-knot-spline-approximation-bsfk-problem?s_t...

etwa 8 Stunden vor | 1

Beantwortet
How do you reshape an array to preserve the order in each row of the original array?
A = magic(3) reshape(A.', [],1)

ein Tag vor | 0

| akzeptiert

Beantwortet
3 subplots with the bottom one split in 2 vertically?
Plenty of examples are given in the doc page https://www.mathworks.com/help/matlab/ref/tiledlayout.html

2 Tage vor | 1

Beantwortet
Speeding up matrix operations
Instead of calling trapz, use matrix multiplication, and this probably beats anything out there in term of speed and memory A =...

5 Tage vor | 1

| akzeptiert

Beantwortet
Speeding up matrix operations
All loops are removed, but the memory requirement might be an issue. As I don't know what mean "very large N, M" I can't make a...

5 Tage vor | 0

Beantwortet
Construct a permutation matrix from two vectors
combinations, new stock function in R2023a a = [1 ; 2 ; 3]; b = [4 ; 5 ; 6]; combinations(a,b)

5 Tage vor | 1

Beantwortet
How to extract diagonal elements of multidimensional array ?
N = 7; A = rand(N,N,N,N,N); p=ndims(A); N=length(A); % Method 1: generalization of cyclist's answer step = polyval(ones...

5 Tage vor | 0

Beantwortet
How to avoid automatic conversion of complex to real?
Yes it works as intended, and no there is no way to disable it. This automatic conversion also affects the CPU and sometime it ...

6 Tage vor | 0

Beantwortet
Is it possible to solve the problem on a permutation set with MATLAB tools?
@potato curious I have function like f(x) = 4x₁+3x₂ and constraints like 3x₁+5x₂<=20, x₁+6x₂>=30. And need to find which permuta...

6 Tage vor | 0

| akzeptiert

Frage

xregion yregion back/front control
I play with the new xregion command (R2023A) The red region is hide by the histogram, not sure why it is not as document exampl...

6 Tage vor | 1 Antwort | 0

### 1

Antwort

Beantwortet
How to know interpolated points in a MATLAB plot?
% Dummy example of some curve that cross the horizontal line y=10 x = cumsum([0 rand(1,40)]); y = 12*sin(x); plot(x,y,'.-'); ...

8 Tage vor | 1

| akzeptiert

Beantwortet
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...

14 Tage vor | 0

| akzeptiert

Beantwortet
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*...

17 Tage vor | 1

| akzeptiert

Beantwortet
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(...

17 Tage vor | 0

| akzeptiert

Beantwortet
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...

18 Tage vor | 0

Beantwortet
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...

19 Tage vor | 0

Beantwortet
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...

20 Tage vor | 0

| akzeptiert

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

20 Tage vor | 0

Beantwortet
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...

21 Tage vor | 0

Beantwortet
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...

22 Tage vor | 0

Beantwortet
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 ...

22 Tage vor | 0

Frage

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...

22 Tage vor | 2 Antworten | 0

### 2

Antworten

Beantwortet
what 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...

26 Tage vor | 0

| akzeptiert

Beantwortet
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...

26 Tage vor | 0

| akzeptiert

Beantwortet
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...

27 Tage vor | 0

Beantwortet
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...

27 Tage vor | 0

| akzeptiert

Beantwortet
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 ...

27 Tage vor | 0

Beantwortet
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, ...

27 Tage vor | 1

Beantwortet
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...

28 Tage vor | 1