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Questions tagged [eigenvalue]

The eigenvalue is the factor by which the eigenvector is scaled when multiplied by the matrix.

The eigenvectors of a square matrix are the non-zero vectors that, after being multiplied by the matrix, remain parallel to the original vector. For each eigenvector, the corresponding eigenvalue is the factor by which the eigenvector is scaled when multiplied by the matrix. The prefix eigen- is adopted from the German word "eigen" for "own"[1] in the sense of a characteristic description. The eigenvectors are sometimes also called characteristic vectors. Similarly, the eigenvalues are also known as characteristic values.

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Eigenvectors' corresponding eugenvalues in Python

I have a symmetric 3*3 matrix, A: A = np.mat("1, 2, 1; 2, 5, 0; 1, 0, 5") I have calculated the eigenvalues of A, which is 0, 6 and 5. I have now been told that A has the following three eigenvectors, and I am asked to find the corresponding three…
user12541161
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Sparse Matrix Coding in Matlab

I have a dataset in which I have a 25,000 by 25,000 matrix for each timepoint with around 60% of the cells being zeroes. I need to be able to take the eigenvalues of my matrices and reorder the columns and rows. Currently, I am running into memory…
vins
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How it is possible to calculate only one eigenvector for one eigenvalue lambda=1 on C++ as efficiently as possible

С++ have a very efficient algorithm to calculate eigenvalues and eigenvectors in MKL library with function dgeev. But it calculates all Eigenvalues, and all left and rirhgt eigenvectors. DGEEV Example Program Results Eigenvalues ( 2.86, 10.76)…
petr
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How to sort a list of tuples by the first value when a key is given in the input to decide whether the sort is ascending or descending?

I'm trying to sort a list of tuples by the first value in ascending or descending order based on the order variable in the input being 'ascending' or 'descending'. i tried something like this code below but didn't work. can you please help me…
VishwaV
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Eigenvalues not following order while changing parameter in Python

I have a 6x6 matrix H of which two eigenvalues become complex at certain values of the parameter l (for lambda). Apparently they are the first two elements of the eigenvalue array E we after diagonalizing H (calling np.linalg.eig module). However,…
hbaromega
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How to find the eigenvalues in Python with a matrix different to the identity matrix

I am trying to find the eigenvalues of a characteristic equation in Python, the problem is that in the equation |A-lambda I|=0, the matrix that multiplies lambda isn't the identity matrix, but I have to make clear that this matrix different to the…
Juan Manuel J
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How do I solve the problem the eigenvalue is very slow to be solved analytically？

I'm very upset this code doen't run a result,it just running all the time.I think the reason is the analytic derivation process which need a analytic solution of matrix W. I hope someone would give me some help or point the problems,I will be very…
Mengr
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Warning while I am calculating eigenvalues

I have to calculate the eigenvalues and eigenvectors, but I always have this warning. I hope someone can tell me what's going on. #masa en kg m1=559.3e-3 m2=419.4e-3 m3=m2 m4=m2 m5=m2 m6=m2 m7=m2 m8=m2 #rigidez en N/m k=56.7e3 #matrices de masa y…
Rafael Inostroza
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Another follow-up to numpy.linalg.eig and loading

Anyway, I'm still struggling with the task of 1) Calculating the eigenvalues and eigenvectors of a matrix, 2) Saving them to a file, 3) Loading the data back. I can do steps 1 and 2; but no matter what I try step 3 always throws an error. See…
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Recovering eigenvalue with largest real part, out of a set of complex eigenvalues, using eigs

I'm using eigs, in order to solve a generalized eigenvalue problem of sparse matrices that comes from the companion linearization of a quadratic eigenvalue problem. In short, the process to compute the eigenvalue is as follows: Having the matrices…
Simos Papadimitropoulos
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Why do I get complex eigenvalues of a Hermitian matrix?

I have defined a Hermitian matrix H which is a sum of Hermitian matrices sigma_x,sigma_y and sigma_z. When I compute the eigenvalues of this matrix, they turn out to be complex numbers (with a non zero imaginary part). import numpy as np import…
Tanmay Bhore
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How calculate eigenvalue, matrix without eigen function in r

I want to implement eigen vectors and values without a function(eigen). Hand calculations in simple matrices are possible, but it is hard to think about to implement them in r. I want a code that can be used in all x matrixs (n x p). I would be…
kimwonjeong
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issue in getting unsorted eigen values

I want to extract linearly independent samples from a matrix. For which I want to use eigen values. But the issue is numpy/scipy based functions give sorted list of eigen values. Through which I loose the information that which eigen value…
shaifali Gupta
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Only point or scatter plot allowed in Python: plotting eigenvalues in a loop

I have the following simple code: import numpy as np import matplotlib.pyplot as plt from scipy import linalg for i in range(10): M=np.array([[i**2,0],[0,i**3]]) # 2 x 2 matrix eval,evec=np.linalg.eig(M) # Plotting first…
hbaromega
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Finding out eigen values and vectors of huge sparse matrices in python is horribly slower than Matlab

I am trying to find 100 eigen values and vectors of a huge sparse matrix of size 409600x409600. I am using scipy.sparse.linalg.eigs for this and it's taking ages to find the result whereas eigs on matlab solves it within 10 mins.Any suggestions on…
S Chakraborty
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