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Bruno Luong


Last seen: Today Active since 2009

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Answered
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 = ...

1 hour ago | 0

Answered
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

2 days ago | 0

Answered
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...

3 days ago | 0

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Answered
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...

3 days ago | 0

Answered
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.

3 days ago | 0

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Answered
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...

3 days ago | 1

Answered
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(:); ...

3 days ago | 0

Answered
Error With Least Squares Approximation
Few other recommendations beside what Torsen and John altrady told you: Lower the polynomial order, do not go above 7, But you ...

5 days ago | 0

Submitted


Free-knot spline approximation
Least squares approximation of 1D data using free-knots spline

5 days ago | 33 downloads |

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Question


ANY and ALL with NaN array
According to any documentation page, it " determines if any element is a nonzero number". OK to me NaN is nonzero number so I do...

6 days ago | 1 answer | 0

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answer

Answered
Make histogram from multiple cells.
% Generate dummy test data C=arrayfun(@(varargin)randn(5+randi(20),24), 1:30, 'unif', 0); A=cell2mat(C(:)); % m x 24, like c...

7 days ago | 0

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Answered
My First Derivative is not correctly calculated in matlab
syms yApprox(X1) a0 a1 a2 a3 a4 a5 a6 yApprox = a0 + a1.*X1 + a2.*(X1).^2 + a3.*(X1).^3+ a4.*(X1).^4 + a5.*(X1).^5 + a6.*(X1).^...

7 days ago | 0

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Answered
for loop vectorization of De Boor algorithm
Old question, but I'll reply it for future readers that wonder how to tackle the same problem. I did a quick and dirdty vectori...

7 days ago | 0

Answered
Increase plot speed in MATLAB
Try to look at animatedline command Also look at drawnow with or without limitedrate option, it somewhat has certain effect, ev...

10 days ago | 0

Answered
Error calculating inverse for matrix block of LU decomposition of a full row rank matrix
It's a little bit perturbant, but reading the lu doc I don't see why U1 must have the same rank than U (or A, meaning 100 on you...

11 days ago | 0

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Answered
de boor bspline algorithm
A very late answer, but as I deal myself with de Boor algorithm I look what exists out there. If the question concerns the 3D a...

11 days ago | 0

Answered
For a repeated eigenvalue only one eigenvctor is being returned
Indeed in case of eigenvalue with multiplicity > 1; the problemie is numerical challenging and MATLAB might fail to find the cor...

11 days ago | 0

Answered
How "chol" and "qz" MATLAB algorithms are utilised in the "eig" MATLAB function?
See stage 3 described in https://netlib.org/lapack/lug/node56.html or somewhere in this file

15 days ago | 0

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Answered
steps to convert spline from B-form to pp-form (fn2fm)
The pp-form stores the polynomial of each each subiterval, the variable is x := (t-ti) where ti is the left knot of interval #i....

15 days ago | 0

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Answered
How to extract a matrix of values from cell array of cell arrays of structs
Generate data (Thanks Voss) n1 = 3; n2 = 4; mse = cell(1,n1); for ii = 1:n1 mse{ii} = cell(1,n2); % row vector for...

27 days ago | 0

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Answered
Where is dlfeval tracing information stored?
I don't kwow the dlarray class but IMO it looks like the creating function handle f is stored in some sort of private property i...

1 month ago | 0

Question


Default rank revealing tolerance
In few MATLAB functions such as RANK, PINV, ORTH there is a parameter TOL. MATLAB uses the default value as % tol = max(size(A...

1 month ago | 0 answers | 1

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answers

Answered
plot() and fplot() give different results for the same function
Your coding is wrong: Replace "/" with "./"

1 month ago | 0

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Answered
getting warning while using eigs on the matrices obtained from freefem++
Try to follow the suggestion you get " Consider specifying a perturbed numeric sigma value to improve the condition of the matri...

1 month ago | 0

Answered
cubic spline interpolation - mixed boundary conditions possible?
In principle yes. The spline on the second segment (b,c) are piecewise cubic poynomials; starting from b sequentially to each in...

2 months ago | 0

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Answered
How to convert /map uint16 to int16 maintaining the dynamic range so that [0] and [2^16-1] in uint16 beomes [-2^15] and [2^15-1] without going through double
If you have C compiler this simple mex file will do the job: /*****************************************************************...

2 months ago | 1

Answered
Faster/better conversion than using swapbytes typecast on udp byte datastream?
Try this: %% Exampel data data =[0 5 187 8 1 136 61 48 0 0 0 0 1 67 58 246 255 127 176 76 10 231 55 137 255 240 253 91 255 22...

2 months ago | 0

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Answered
How to add extra columns at specified locations
After computing dataset2 dataset = [1, 2, 3, nan, 4, 5, nan, 6, 7]; % ... dataset2 = [2, 5, 7, 8, 4, 8, 10]; do this: da...

2 months ago | 0

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Answered
scrit can't error related to Sortrows and matrix
Replace initialization statements sol=[]; % Start with an empty matrix of feasible solutions data = []; with sol=zeros(...

2 months ago | 0

Answered
Max Recursion even when using clear
Don't name your script function clear.m. In command windows type which clear then rename or remove that file to restore the bu...

2 months ago | 0

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