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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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Eigenvalues for matrices in a for loop

I need to calculate eigenvalues of a series of matrices and then save them in a separate file. My data has 5 columns and 10,000 rows. I use the following functions: R<-NULL A <- setwd("c:/location of the file on this computer") …
ShazAl
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eigen; get not normalized eigenvector

Note: I'm probably doing something that isn't supposed to be & my eigen knowledge is pretty limited but couldn't find what I look for. I'm currently using eigen to get the direction vector of a pointcloud line. //Compute eigenvalues and…
A.albin
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Inaccurate zheev eigen values and vectors

I use the LAPACK zheev routine in a Fortran scientific code to compute both eigenvalues and vectors of a matrix not too big (likely to never exceed size 1000). Since this step happens at the beginning of the computation I have to achieve a great…
WIP
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Eigenvalues are always 1

When I get the eigenvalues of the diagonal of a PCA transformed image, I always get 1, whatever the image. What's the reason behind this? I used the following code. coeff = pca(pmap); disp(coeff); [V,L]=eig (coeff'*coeff); Lamda =…
N.Chandimali
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Numpy- Find Corresponding Eigenvectors of a Particular Set of Eigenvalues

I'm trying to figure out how to find the corresponding eigenvectors of a particular set of eigenvalues with numpy. I'm working on a project using Singular Value Decomposition, and I need to find Truncated SVD, which is the SVD with the k-largest…
SamTulster
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Reading symmetrical Harwell-Boeing matrix in Python

SciPy can read only read unsymmetric matrices with hb_read. Anyone know if it is possible to read symmetric matrices in Python (3)?
edub
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Map 2d float array into eigen matrix using the eigen library

I have a 2d covariance float array of size 10000 by 10000 and i would like to get the eigenvalues by using the eigen libary.For that,i need to store the 2d covariance float array into an eigen matrix A of float type and then use eigensolver to get…
MOUSE
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Bootstrapping eigenvalues for nonlinear PCA in r

I am running nonlinear PCA in r, using the homals package. Here is a chunk of the code I am using as an example: res1 <- homals(data = mydata, rank = 1, ndim = 9, level = "nominal") res1 <- rescale(res1) I want to generate 1000 bootstrap estimates…
Eszter
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Code for power method to find all eigenvalues and eigenvectors ( in R)

I have no trouble implementing a code to find the biggest eigenvalue, and corresponding eigenvector of a matrix using the power method. What I have more trouble with, is thinking of a code that can output all eigenvalues and eigenvectors of a given…
Joel H
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python: Not enough memory to perform factorization

I am using python sparse module to compute a eigenvalue problem. It is a very big sparse matrix, which would end up with large memory requirement. But the strange thing is I am using a cluster with 256GB memory which should be definitely enough for…
Yongxiang Wu
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Error while calculating eigen vectors and eigen values using the modred module in python

I am trying to calculate the orthogonal decompositions using the modred module in python. When the code executes the following lines: > myPOD = mr.PODHandles(inner_product,max_vecs_per_node=20) eigvals, > eigvecs =…
sin123
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accessing eigenvalues in RSSA package in R

I am using RSSA package in R and I need to access the eigenvalues. using the following code I can plot the components. However, I need to access all eigenvalues as numbers. require(Rssa) t=ssa(co2) plot(t)
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Finding dominant eigenvector and eigenvalue

I calculated the eigen of a matrix: e <- eigen(t) Now I need to get the dominant eigenvalue and dominant eigenvector Is the dominant eigenvalue calculated: e$values[1] And what about the dominant eigenvector? Is it extracted by: e$vectors[,1] I…
user42967
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error in computing eigen values

I am trying to find eigen values for a syymetric matrix as follows:- Mat t(2, 2, CV_32F); t.at(0, 0) = 1; t.at(0, 1) = 0; t.at(1, 0) = 0; t.at(1, 1) = 128; Mat eigVal,eigVec; …
Anirudh
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Eigenvalue calculation using TQLI algorithm fails with segmentation fault

I am trying to calculate eigenvalues using the TQLI algorithm that I got from the website of the CACS of the University of Southern California. My test script looks like this: #include int main() { int i; i = rand(); …
Axel
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