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# Bruno Luong

Last seen: en dag ago Active since 2009

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Supplying gradient for the subset of parameters
May be you could provide the gradient interface for all, but compute the subset derivative analytically and the complement by fi...

ungefär 10 timmar ago | 0

Matrix algebra AxB=C, I want to solve for B
You can't recover the "original" B, whatever it is, your system is underdetermined (much more unknowns - 1826 - than equations -...

ungefär 17 timmar ago | 1

How can I assign zeros to a particular value in an expression
test function test N =4; u = (1:N); v = (N:2*N-2); function ui = getu(i) if i <= 0 | i >= 4 ui = 0; else ui =...

en dag ago | 0

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How to find x value for a known y in array plot?
* x = linspace(-3,3); Assuming your data are monotonic on the neighborhood of the max y = exp(-x.^2); [maxy, imax] = max(y...

en dag ago | 0

pause() function is inaccurate
The accuracy is documented. "The accuracy of the pause function is subject to the scheduling resolution of your operating syste...

en dag ago | 1

fminsearch is an mfile, you can copy it then mofify these lines #196 (R2022a) % Set up a simplex near the initial guess. % PUT...

en dag ago | 0

How to reduce the usage of "broadcast variables" when using parfor
You can use parallel constant to convert el, el_row1, ds, vmin to constant and reduce the data transfert, if they are not modifi...

en dag ago | 0

Concatenate arrays of different length inside loop
What's wrong with cell? vox_count_cell = cell(1, length(image_files)); for i = 1:length(image_files) header = spm_vol(ima...

en dag ago | 0

"it returns the initial value" It indicates that the fit fails, not problem of wrong stating points (converge to local minima)....

en dag ago | 0

solve equation numerically 1=(1/y)x*exp(x*y)
Numercial solution y = 0.01:0.01:1; x = nan(size(y)); for k=1:length(y) yk = y(k); x(k) = fzero(@(x)x.*exp(x.*yk)-y...

en dag ago | 0

How to interpolate missing z-values: looking for ideas
You might try this inpaint_nans FEX by John d'Errico

2 dagar ago | 0

How can I find negative factorial ? (-0.5)!
There are actually different ways of extending factorial function, see here http://www.luschny.de/math/factorial/hadamard/Hadam...

2 dagar ago | 1

install standalone application on macOs, that was compiled on windows
" According to Matlab, I think it should be possible (https://de.mathworks.com/help/compiler/install-deployed-application.html) ...

2 dagar ago | 0

Remove all rows of an array based on a value in a column, and also remove all rows that have the same values as this row in other columns
M = [ 15.88 18.43 15.88 18.43 0 15.88 18.43 33.48 14.99 ...

3 dagar ago | 0

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why is acumarray much slower calculating means than sum?
The default behavior of accumarray is sum and it's low-level coded. When you pass user-defined function MATLAB will call the fu...

3 dagar ago | 2

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Question

reduction variables and evaluation order
This the doc on can read "A reduction variable accumulates a value that depends on all the iterations together, but is independ...

3 dagar ago | 1 answer | 1

### 1

[PR1Data.filename] = deal(''); or if you PR1Data is non empty PR1Data(1).filename = '';

3 dagar ago | 1

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Faster way to create a matrix of the unique() of each row of a matrix
% Test example A=randi(4,10,5) [m,n] = size(A); As=sort(A,2); b=[true(m,1),diff(As,1,2)>0]; R=repmat((1:m)',1,n); C=cums...

4 dagar ago | 1

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How to create 3D matrix with empty cells
cell(3,3,3) % replace 3 with 300 for you I'm still afraid you'll be soon in trouble if you ask such question about easy data cr...

4 dagar ago | 0

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Fit coefficients are equal (to starting points) in 3000 different fits
Can you do check whereas they are identical with this command after the loop isequal(Coefficients(:,10),Coefficients(:,2999)) ...

5 dagar ago | 0

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How to find the intersection of multiple arrays (or rows of a matrix) in a short code
Put in the cell then use comma list systax: c = {a, b, c, ...}; % or use mat2cell, num2cell depends how you store your 172 vect...

5 dagar ago | 1

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2D Interpolation of data
You have scattered data, you should use scatteredInterpolant or similar, not interp2.

5 dagar ago | 0

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Do this when loading, Container = load('Saving.mat'); Saving = Container.Saving; Check out doc of save ans struct so you won...

5 dagar ago | 1

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scatteredInterpolant function is providing too much noise in interpolation
The problem raises from the fact that scatteredInterpolant use Delaunay triangulation, meaning that X and Y are assumed to have ...

5 dagar ago | 1

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Without resorting to FEX/MEX, can the overhead of repeated calls to sparse() be avoided with operations on I, J, V directly?
EDIT: Here is the final code. Method used in B2 is the fatest; M = 10000; N = 10000; N_k = 100; A_k = cell(1,N_k); for k=1:...

5 dagar ago | 0

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Does intlinprog use cuts during its Branch and Bound Algorithm?
The document CutMaxIterations: Number of passes through all cut generation methods before entering the branch-and-bound phase,...

5 dagar ago | 0

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Vectorized way to assign columns/rows of matrix to struct array's field
split = num2cell(matrixToAssign,1); [structArray.field] = deal(split{;});

5 dagar ago | 0

What is the best smoothing procedure to calculate differentials for a large number of data points (x,y)?
The Savitzky-Golay filter (moving polynomial fit) is a good filter that preserves decendly the slope. There is a similar thread...

6 dagar ago | 2