Bruno Luong

Last seen: Today

1.583 total contributions since 2009

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Answered
matrix in special arrangment for cycler gemetry
>> A=[11 12 13 14 15] A = 11 12 13 14 15 >> toeplitz(A,A) ans = 11 12 13 14 15 ...

alrededor de 6 horas ago | 0

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Answered
how matlab stores graphics objects?
All graphic objects are class "handle". Handles is a identify to designate the object and it's obviously 8 bytes as showed by wh...

alrededor de 7 horas ago | 0

Answered
speeding up my for loop
function y=divisors2(N) f = factor(N); [~,~,J] = unique(f); n = accumarray(J,1); y = prod(n+1); end Test >> N=27022021 ...

alrededor de 7 horas ago | 1

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Answered
Check if nullspace is contained in another + finding intersection of 2 nullspaces.
First question: KA = null(A); KB = null(B); % Check span KA is included in span KB PKA = KB*(KB'*KA); % Projection KA on ...

alrededor de 10 horas ago | 0

Answered
How can I get randperm to return a permutation of a vector that has no entries at their original positions?
This will do what you ask for https://www.mathworks.com/matlabcentral/fileexchange/30189-randpermfull?s_tid=srchtitle Even bet...

alrededor de 13 horas ago | 0

Answered
Theory of Bicubic interpolation
It has been answered here https://www.mathworks.com/matlabcentral/answers/78116-algorithm-of-bicubic-interpolation In 2D you d...

4 días ago | 0

Submitted

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

4 días ago | 24 downloads |

Answered
Finding LAT LONG inside a circle of a given LAT LONG .
% Random data lonA=rand*360; latA=rand*180-90; n = 10000; lonP=rand(1,n)*360; latP=rand(1,n)*180-90; earthradius = 6357;...

8 días ago | 0

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Answered
HELP. Need to understand MATH behind scatteredInterpolant or Interp2 function
"Based on the equation that I had in that screen shot would you assume that the other model is using a simplified linear interpo...

10 días ago | 0

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Answered
How to generate a nearly symmetric matrix?
Just generate first a symettric matrix then perturb a "the overwhelming minority" of elements. Whatever that definnition means....

10 días ago | 1

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HELP. Need to understand MATH behind scatteredInterpolant or Interp2 function
Run this, that show the "formula" and how to get zq = -38.5561 zq_check = -38.5561 Code to check 'linear' met...

10 días ago | 0

Answered
In a vector, how to remove neighbours too close from one another
Using stock function >> uniquetol([1 6 12 17 23 25 34],10,'DataScale',1) ans = 1 12 23 34 Jan's various ...

15 días ago | 2

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Generate random integers that sums to a specific number within a specific range
Unfortunately the uniform distribution with bounds for integer is much more challenging. One way is to approximate by rounding t...

17 días ago | 0

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How to calculate the pairwise distince between two dataset without any loop
If you have latest MATLAB release (for pagemtimes) and download this Multiple same size solver FEX X = [1 2 1;3 4 2;5 6 3] Y =...

20 días ago | 0

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Answered
How could I separate the geometry data from single stl file contains multiple objects by stlread?
You can use conncomp of the triangulation graph data=stlread('research_stl_read.stl'); s=data.ConnectivityList(:,[1 2]); t=...

24 días ago | 1

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Why the abbrevation of "Left side of equation" is "lhs"
left hand side

25 días ago | 2

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Answered
How to Find the Rotation Matrix?
You equation is NOT enough to determine the third column, you forget about the orthogonal conditions and that det(R)=1 (rotation...

26 días ago | 3

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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 1 mes ago | 2

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Answered
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...

alrededor de 1 mes ago | 1

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Answered
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...

alrededor de 1 mes ago | 2

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Answered
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...

alrededor de 1 mes ago | 1

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Answered
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...

alrededor de 1 mes ago | 1

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Answered
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...

alrededor de 1 mes ago | 2

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

alrededor de 1 mes ago | 0

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

alrededor de 1 mes ago | 1

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Answered
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 ...

alrededor de 1 mes ago | 1

Answered
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...

alrededor de 1 mes ago | 1

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

alrededor de 1 mes ago | 0

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

alrededor de 1 mes ago | 0

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Answered
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 ...

alrededor de 1 mes ago | 0

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