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Bruno Luong


Last seen: ein Tag vor Aktiv seit 2009

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Beantwortet
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 =...

ein Tag vor | 0

| akzeptiert

Beantwortet
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...

ein Tag vor | 0

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Beantwortet
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...

3 Tage vor | 0

Beantwortet
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...

4 Tage vor | 1

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Beantwortet
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...

4 Tage vor | 0

Beantwortet
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...

4 Tage vor | 0

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Beantwortet
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)...

4 Tage vor | 0

Beantwortet
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 Tage vor | 1

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Beantwortet
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 Tage vor | 0

Beantwortet
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 Tage vor | 0

Beantwortet
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 Tage vor | 0

Beantwortet
How to fit a sine curve with only the maximum and minimum values
piecewise (co)sine interpolation (not fitting). I don't think you have extra DOF to play with if you restrict data to be local ...

6 Tage vor | 1

Beantwortet
symmetric solutions of linear matrix equations
This is a method that use the small "original" linear system. I use pcg since it a linear solver that can accept function handle...

6 Tage vor | 1

Beantwortet
symmetric solutions of linear matrix equations
If you have tthe optimization toolbox % Generate test matrices n = 3; A = randn(n); X=rand(n); X = X+X.'; B = X*A; % Add s...

7 Tage vor | 0

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Beantwortet
how to multiply every single element in a matrix to entire of another matrix?
x = [100,500,900,1300,1700; 120,600,1080,1560,2040; 140,700,1260,1820,2380; 160,800,1440,2080,2720; 180,900,...

7 Tage vor | 1

Beantwortet
symmetric solutions of linear matrix equations
% Generate test matrices n = 5; A = randn(n); X=rand(n); X = X+X.'; B = A*X; % Add small noise to B B = B + 1e-1*randn(siz...

8 Tage vor | 0

Beantwortet
polyfit step by step or analytics
polyfit is the mfile you can step through in debugging mode. If you call with one outout argument (non normalized) it build van...

8 Tage vor | 0

Beantwortet
Inserting 0 in sparse matrices without changing sparsity pattern?
Is it possible to tell MATLAB to not change the sparse matrix, but instead treat inserted zeros as any other value? Short answ...

9 Tage vor | 1

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Beantwortet
How to fix my linear fit model?
Assuming you know where to split the data for left and right lines: x = [0 1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 17 18 19 20 ......

9 Tage vor | 1

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Beantwortet
How to fix my linear fit model?
This returns the piecewise linear function that is continuous at the break point. The correct break point is close to 18.6054 a...

10 Tage vor | 1

Beantwortet
strcmp gives a 0 while it should be a 1
Look more carefully: There is a 'c' before '49' in A but not in B

12 Tage vor | 0

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Beantwortet
Basic FFT Question: What range to sample the function in.
" However I am under the impression that the fft should not be sensitive to this change. " Your expectation in incorrect When y...

15 Tage vor | 0

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Beantwortet
getfield to get values from an entire struct array?
Create 1 x 3 struct array with field named 'afield' s = struct('afield', {11 12 13}) s(1) s(2) s(3) % Here is the command t...

15 Tage vor | 0

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Beantwortet
express basis spline derivative in terms of interpolation values
x = [1 2 3 4 5]; y = randn(size(x)); k = 5; f = spapi(k,x,y); B = spapi(k,x,eye(length(x))); fdd = fnder(f, 2); Bdd = ...

16 Tage vor | 0

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Beantwortet
Use MATLAB Coder to convert matlab code to mex without using multi-threading
https://www.mathworks.com/help/coder/ug/use-parallel-for-loops.html

19 Tage vor | 0

Beantwortet
How to get all possible combination With the total number of possible combination for "n" variables that can take different values
Checkout similar thread https://www.mathworks.com/matlabcentral/answers/476022-how-to-pick-up-all-combination-of-numbers-from-m...

19 Tage vor | 0

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Beantwortet
Possible issues with solving iterative linear systems with mldivide
"Is there a way to see the matrix solver steps to see which expressions might have an issue?" No they are LAPACK/BLAS based cod...

19 Tage vor | 0

Beantwortet
Sparse matrix vector product returns null.
"What can cause this issue?" Nothing. What you claim likely would not happen. Unless if you show an example.

20 Tage vor | 0

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Beantwortet
How to define if/else non linear constraint in an optimization problem
Simply solve three different optimization pbs with the three repectively constraints independently and ignore the two other, the...

20 Tage vor | 1

Beantwortet
How to use loop to fill in specific numbers?
T = combinations(1:4,1:8) % for alder release that does not support combinations [v1 v2] = meshgrid(1:4,1:8); v1 = v1(:); ...

20 Tage vor | 0

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