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Do I need to initiate the parallel computing toolbox for my code to run on multiple cores?
MATLAB has many low level functions are multi-thread coded and potentially use all the CPU core. In this case parallel tbx wil...

4年以上前 | 0

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Speeding up to find minimum value using min() function
Alternative way % Fake data c=cumsum(rand(1,10000)); s=c(end)*rand(1,10000); cpad = [-Inf c Inf]; b = discretize(s,cpad);...

4年以上前 | 0

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Can we compute the graph Laplacian matrix for a directed graph?
In this thread I give formula for graph, for digraph you just need to be careful about indegree or outdegree % TMW example s ...

4年以上前 | 1

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Which solver should I use to solve a square and symmetric, linear system of equations?
Don't worry, MATLAB backslash detects automatically the type of your matrix and adapt the method. See "Algorithm" of doc page h...

4年以上前 | 1

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How can the following code be optimized / vectorized?
It takes about 25 seconds only PC Ac35 = A(:,3:5); Ai = reshape(Ac35,[],1,3); B = zeros(SitesInSystem,SitesInSystem); for j=...

4年以上前 | 0

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How to extract the coordinates of points/vertices in a curve?
clear MeshSize = 0.04; LensStr = 'osci'; radius = 1; %% n = ceil(radius/MeshSize); % radial resolution [X,...

4年以上前 | 2

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How to generate a matrix with entries of -1 and +1 of size N x M where all the columns are unique ?
N = 3; M = 5; A = (dec2bin(randperm(2^N,M)-1,N)-'0')'*2-1

4年以上前 | 0

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Obtain the sorted index vector
Use the second output of sort x=[0.5; 0.4; 0.6; 0.9] [y,z] = sort(x,'descend')

4年以上前 | 0

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Reversing a vector in the same line of code
a_vec = [2, 4, -5, 7, 18, 0] flip(a_vec)

4年以上前 | 1

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what is the efficient way to search for value in a large struct
You structure array seems to be linear, I would store the data in a structure of (cell) arrays rather than array of structures. ...

4年以上前 | 0

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About "ismember" function
No loop or arrayfun is needed Var1=["AAA" "AA" "A" "BBB" "BB" "B"]'; Var2=[1 2 3 5 7 13]'; PD=table(Var1,Var2) Var1=["B" "...

4年以上前 | 0

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I have many structs (from an XML file) with some common and different fields. How can I add the missing fields to each struct automatically so that all have the same fields?
I don't read you description, just to post here my tool catstruct s1=struct('a',1,'b',2); s2=struct('b',3,'c',4); s3=struct('...

4年以上前 | 0

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Generate a series of random integers but with consecutive numbers including
A=ones(4,6); A(1,:)=ceil(10*rand(1,size(A,2))); R=reshape(cumsum(A(:)'),size(A)); R=R(:,randperm(end)); R=R(:)'

4年以上前 | 0

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Can this for loop be vectorized?
e_i_h_reshape = reshape(e_i_h,N_i,1,N_draws); alpha_i_h_t = e_i_h_reshape + e_h * t;

4年以上前 | 0

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Why trust-region-reflective algorithm in fmincon require a gradient as input?
I don't think Matt's answer is correct, rather Torsen answer is better. The Trust region algorithm must approximate the objectiv...

4年以上前 | 0

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Nearest Neighbor Matching without Replacement
If you have R2019a release x=rand(1,10) y=rand(1,10) C=abs(x(:)-y(:).'); M = matchpairs(C,max(C(:))); px = M(:,1); xm ...

4年以上前 | 0

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Obtaining half-spaces from the convex hull in MATLAB
% k = convhull(P), the half spaces form is {x such that A*x <= b} with W=P(k,:); V=W(1:end-1,:); A=(W(2:end,:)-V)*[0 -1; 1 0]...

4年以上前 | 0

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How can I sort intersections points given from polyxpoly according to order of appearence?
Some modifications based on this FEX x = cumsum(rand(1,10)); % Generate random P1 and P2 x = x/max(x); y = rand(size(x)); ...

4年以上前 | 1

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How do I find if the three arrays of unequal size have the same values?
Use FEX mintersect i1 = [1 3 4]; i2 = [4 4 2 5]; i3 = [5 4 1 5 3 3 2]; mintersect(i1, i2, i3)

4年以上前 | 0

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Generating n bit random numbers with each bit sampled N times.
n=8; % number of bits r=10; % number of bit repetitions, 100 in your case m=20; % number of sequenes (>=r) i=zeros(r,n); for...

4年以上前 | 0

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Solving constrained optimization problem
A=randn(6,2) [h,lambdamin] = svds(A.',1,'smallest')

4年以上前 | 1

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Matlab order of operators
"`C\D'` should be equal to finding the `x` s.t. `C=(D')*x`." No. Rather D' = C*x Your code should be while true C =...

4年以上前 | 0

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How does 'unique' work under the hood (in general terms)
If I have to implement unique, I would implemented by sorting the find the difference similar to this a=randi(10,1,100); % u i...

4年以上前 | 1

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質問

sum on empty arrays
Can someone explain the logic of third statement (Run under R2021b) : sum(zeros(0,0)) sum(zeros(1,0)) sum(zeros(2,0)) % This ...

4年以上前 | 1 件の回答 | 0

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Tiff class: Tile setting
I'm confused in setting two parameters TileLength and TileWidth for Tiff object when my data is an 3D array (m x n x p). In the...

4年以上前 | 1 件の回答 | 0

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Vectorizing loop containing multiplication of a scalar and a matrix
w = [0.2,0.5,1,0.5,0.2]; i=reshape(1:length(w),1,1,[]); z = zeros(size(i)); s=sum([i-1, i, 0+z; i, i+1, 0+z; 0+z, 0+z, 1+z].*...

4年以上前 | 0

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mldivide (backslash): advantage by using sparse matrix instead of a full matrix with respect to the quality of the results?
If your condition is 3.65e27 you wi=on't get any reliable solution regardless the method. The full matrix use QR with permutati...

4年以上前 | 3

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histc vs. histcouns
The result differ by the way the last bin is handed in both function. To get the same result you must change the last edge to In...

4年以上前 | 1

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2×2 matrix
c=cell(2*2,1); [c{:}]=ndgrid(1:8); a=reshape(cat(5,c{:}),[],2,2); a=permute(a,[2 3 1]); disp(a)

4年以上前 | 0

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Cholesky factorization: How to change code to produce A = L' * D * L instead of A = L * D * L' .
% Generate random symetric A A=randn(5); A=A'+A; disp(A) [L,D]=ldl(A); disp(L*D*L') [L,D]=ldl(rot90(A,2)); L=rot90(L,2)...

4年以上前 | 0

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