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# Bruno Luong

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1.567 total contributions since 2009

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Shortest path in a 2d matrix
%W=[ 1 2 3; % 4 5 6; % 7 8 9 ] W = randi(9,5,5) % Build the 4-connected graph [m, n] = size(W); [i, j] = ndgrid(1:m,1:n)...

alrededor de 23 horas ago | 1

Selecting a "random" element from an array with each element having it's own weighting
A=[1,2,3,4]; p=[10 20 30 40]; c=cumsum(p); [~,r]=histc(rand(1,1e6),[0 c/c(end)]); % generate 1e6 numbers r=A(r); % Chec...

1 día ago | 1

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A QR complexity question
The O(n^3) is number of flops, which is not proportional to tic/toc. You time also RANDN Calling QR has overhead that is signi...

2 días ago | 2

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How to Solve this Big System of Equations
Possible causes: your matrix is wrongly constructed you forget to include proper boundary conditions you forget to add condit...

2 días ago | 1

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fill matrix with all options of successive, increasing numbers 1-5
p = 5; n = 12; j = nchoosek(2:n,p-1); m = size(j,1); % == nchoosek(n-1,p-1) == 330 and not 96 i = repmat((1:m)',1,p-1); A...

2 días ago | 1

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How do I find a D matrix that satisfies [K]*inv(M)*[D]==[D]*inv(M)*[K] ?
You have homogeneous linear equation, the entire null space of operator (D considered as input) K*inv(M)*D-D*inv(M)*K (dimensi...

2 días ago | 1

Remove overlapping intervals from two array intervals without using a loop
You might interest to use my interval-merging FEX

4 días ago | 0

Plotting a smooth curve from points
Direct analytic method using piecewise cublic polynomial. The curve is first-order differentiable, but not second order differen...

4 días ago | 1

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Plotting a smooth curve from points
No extra points needed (but you might add to twist the shape of the curve in the first and last interval), Spline order >= 8th ...

4 días ago | 1

How to calculate the volume enclosed by a set of XYZ points in 3D?
V is the volume between the plane x-y (z==0) and the surface z(x,y) from your data. If you want the volume of the data after su...

5 días ago | 1

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How to triangulate a non-convex ordered set of points?
I recommednd this Mesh2D FEX

5 días ago | 0

Vectorizing issue in MATLAB
It is in general not possible to vectorize sequential calculation like yours.

7 días ago | 0

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How to find out a smallest sub-matrix B from a sparse matrix A which has the equal rank and # of non-zero columns?
Done, B=A (so all rows of A) meets your requirement >> A = [ 1 -1 0 0 0 0 0 0 0 1 ...

7 días ago | 0

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Converting a 3D Matrix to multiple 2D matrices
Assuming A is array 1000 x 1000 x 40 C = num2cell(A,[1 2]);

11 días ago | 1

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Multiply all pages of a matrix
AFAIK there is no alternative way in general; unless your matrices has special property that can use some simplification.

13 días ago | 0

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I can't see addpath in your snip of code. When you compile the app, all the source mfiles used by you app MUST be found by depe...

13 días ago | 0

Matlab interpolation between two surfaces
Assuming your two original surfaces are z1 and z2, juts pick w scalar in (0,1) interval, zinterp = (1-w)*z1 + w*z2; If w == 0 ...

13 días ago | 0

Matlab executable not running on remote access files
"I would like to change the directories for reading and writing theses files." IIRC the cd command is non effective in deployed...

13 días ago | 0

Question

Answers editor seems to be broken
I can't see the editor tool in some PC display config + Firefox After a simple view of the thread it ask me as if I would edit ...

14 días ago | 1 answer | 0

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Question

Is FORMAT DEBUG still any useful?
Can someone has an explanation for this (R2020B) clear clc x=1; y=x; x=x+1; format debug y x that produces y = ...

15 días ago | 1 answer | 1

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Two linear equation with absolute value equation
Correct minimum norm solution is xmin = 90.0000 -40.0000 5.0000 5.0000 normxmin = 98.7421 obtain...

15 días ago | 1

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Rearranging a 512x64 matrix into a 32x1024 matrix
% Assuming A is your input matrix of size 512 x 64 % such as % A=reshape(1:512*64,64,512)'; B = reshape(permute(reshape(A,[...

15 días ago | 1

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generate random number with total sum is 10
For the case of more generic sum of n variables Xi is equal to 1. If the apriori distribution is supposed to be uniform density...

15 días ago | 1

Is fmincon appropriate for optimizing vector-valued optimization variables (scalar obj. function)?
Yes fmincon supposes to handle optimization problems on objective function that depends on vector of real values. There is no re...

15 días ago | 0

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How do I map array values on a logical array
Result = zeros(size(B)); Result(B==1)=A

16 días ago | 1

Find the line where 2 planes intersect
% Planes implicit equations are: % a1*x + b1*y + c1*z = d1; % a2*x + b2*y + c2*z = d2; % a1 = 256; b1=0; c1=0; d1=0; ...

16 días ago | 1

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subsref works as not expected
I knew it for sometime: subsref never work to emulate comma list (not sure if it's documented), because a non trivial comma list...

16 días ago | 0

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There is https://www.mathworks.com/help/optim/ug/coneprog.html but only for linear objective function. You migh iterate on b...

16 días ago | 0

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