eigenvector Questions

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I've got a lower triangular MatrixXd and I want to copy its lower values to the upper side as it'll become a symmetric matrix. How can I do it? So far I've done: MatrixXd m(n,n); ..... //do ...
Cusk asked 22/8, 2012 at 13:52

2

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I create an arbitrary 2x2 matrix: In [87]: mymat = np.matrix([[2,4],[5,3]]) In [88]: mymat Out[88]: matrix([[2, 4], [5, 3]]) I attempt to calculate eigenvectors using numpy.linalg.eig: In [9...
Seldon asked 3/10, 2015 at 19:54

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I want to compile the following example based on Eigen's general eigenvalue solver (Eigen 3.3.3): #include <iostream> #include <Eigen/Eigenvalues> int main() { Eigen::Matrix4f A; A ...
Barbarize asked 9/4, 2017 at 12:7

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I'm trying to use networkx to calculate the eigenvector centrality of my graph: import networkx as nx import pandas as pd import numpy as np a = nx.eigenvector_centrality(my_graph) But I get th...
Henrieta asked 4/4, 2017 at 13:31

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As a current task, I need to calculate eigenvalues and eigenvectors for a 120*120 matrix. For start, I tested those calculations on a simple 2 by 2 matrix in both Java (Apache Commons Math library)...
Psychosomatic asked 15/11, 2016 at 13:6

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My purpose is to find a eigenvectors of a matrix. In Matlab, there is a [V,D] = eig(M) to get the eigenvectors of matrix by using: [V,D] = eig(M). Alternatively I used the website WolframAlpha to d...

2

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I wrote a simple Linear Algebra code in Python Numpy to calculate the Diagonal of EigenValues by calculating $M^{-1}.A.M$ (M is the Modal Matrix) and it's working strange. Here's the Code : impor...
Dosage asked 3/4, 2016 at 21:1

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I have a very large sparse matrix which represents a transition martix in a Markov Chain, i.e. the sum of each row of the matrix equals one and I'm interested in finding the first eigenvalue and it...
Salvation asked 24/8, 2015 at 14:32

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In MATLAB I can issue the command: [X,L] = eig(A,'nobalance'); In order to compute the eigenvalues without the balance option. What is the equivalent command in NumPy? When I run the NumPy ver...
Colly asked 17/12, 2013 at 3:42

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I'm newbie in C++ programming, but I have a task to compute eigenvalues and eigenvectors (standard eigenproblem Ax=lx) for symmetric matrices (and hermitian)) for very large matrix of size: binomia...
Moguel asked 28/8, 2015 at 10:32

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I'm creating a visualization to illustrate how Principal Components Analysis works, by plotting Eigenvalues for some actual data (for the purposes of the illustration, I'm subsetting to 2 dimension...
Ramiah asked 22/5, 2015 at 14:8

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I was doing some matrix calculations and wanted to calculate the eigenvalues and eigenvectors of this particular matrix: I found its eigenvalues and eigenvectors analytically and wanted to confi...
Dari asked 22/4, 2015 at 13:28

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Short version of my question: What would be the optimal way of calculating an eigenvector for a matrix A, if we already know the eigenvalue belonging to the eigenvector? Longer explanation: I ha...
Osmium asked 26/3, 2015 at 22:44

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Is there a more elegant solution than to copy the values point to point?! Something like this works for a 1D vector... vector<float> vec(mat.data(), mat.data() + mat.rows() * mat.cols()); ...
Evanesce asked 24/3, 2015 at 20:40

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I would like to implement the Power Method for determining the dominant eigenvalue and eigenvector of a matrix in MATLAB. Here's what I wrote so far: %function to implement power method to comput...

1

I have used Jacobi method to find all eigenvalues and eigenvectors in c code. Though the complexity of Jacobi method is O(n^3) but the dimension of my matrix is huge (17814 X 17814). It takes a lot...
Hoyden asked 19/3, 2015 at 8:38

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I have a matrix such as this example (my actual matrices can be much larger) A = [-1 -2 -0.5; 0 0.5 0; 0 0 -1]; that has only two linearly-independent eigenvalues (the eigenvalue -1 is repeate...
Midiron asked 3/9, 2013 at 20:57

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Consider singular value decomposition M=USV*. Then the eigenvalue decomposition of M* M gives M* M= V (S* S) V*=VS* U* USV*. I wish to verify this equality with numpy by showing that the eigenvecto...
Calendula asked 5/1, 2015 at 14:46

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In MATLAB, when I run the command [V,D] = eig(a) for a symmetric matrix, the largest eigenvalue (and its associated vector) is located in last column. However, when I run it with a non-symmetric ma...
Mcclure asked 20/7, 2010 at 15:43

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I have a matrix 100x100 and I found it's biggest eigenvalue. Now I need to find eigenvector corresponding to this eigenvalue. How can I do this?
Zeta asked 20/5, 2013 at 14:25

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While trying to compute eigenvalues and eigenvectors of several matrices in parallel, I found that LAPACKs dsyevr function does not seem to be thread safe. Is this known to anyone? Is there some...
Jhelum asked 13/8, 2013 at 18:17

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Let's generate an array: import numpy as np data = np.arange(30).reshape(10,3) data=data*data array([[ 0, 1, 4], [ 9, 16, 25], [ 36, 49, 64], [ 81, 100, 121], [144, 169, 196], [225, 256, 289...
Donia asked 12/11, 2013 at 17:45

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I am calculating eigenvectors in Matlab and Numpy, but getting different results. I was under the impression there was only one set of eigenvectors for a given matrix, however both of these outputs...
Gastrula asked 18/9, 2013 at 23:51

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I am trying to find the eigenvalues/vectors for the following matrix: A = np.array([[1, 0, 0], [0, 1, 0], [1, 1, 0]]) using the code: from numpy import linalg as LA e_vals, e_vecs = LA.eig(A)...
Jeromyjerreed asked 12/9, 2013 at 18:11

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I'm trying to write a program that gets a matrix A of any size, and SVD decomposes it: A = U * S * V' Where A is the matrix the user enters, U is an orthogonal matrix composes of the eigenvector...
Attainture asked 9/8, 2013 at 17:9

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