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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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how could I know which dimensions are the principle component?

I use matlab's princomp function to do PCA. From my understanding, I could check the latent to decide how many dimensions I need. [coeff, score, latent, t2] = princomp(fdata); cumsum(latent)./sum(latent); And by using trainMatrix = coeff(:,1:10)…
Freya Ren
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How can I use GotoBlas library in VS2010 C++ on Windows 7?

I downloaded GotoBLAS library at http://www.tacc.utexas.edu/tacc-projects/gotoblas2/ and I want to use syev() function to calculate eigenvectors and eigenvalues of a matrix. But I'm a newbie with opensource library and I don't know how to use it?…
Alex Rover
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Eigenvalues vs PVE (percent variance explained)

With prcomp() function, I have estimated percent variance explained prcomp(env, scale=TRUE) The second column of summary(pca) shows these values for all PCs: PC1 PC2 PC3 PC4 PC5 PC6 PC7 Standard…
cryptic0
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Calculating eigenvalues of an infinite banded matrix using LAPACK

I'm new to C++ and am trying to figure out how to use LAPACK to find the eigenvalues of an infinite banded matrix (anharmonic oscillator problem). I know that I'm calculating the matrix correctly as I've checked the values and they all match up. …
opes
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Converting A Fortran77 Code To Matlab Code for finding eigen values/vectors

I converted a written code in fortran 77 to Matlab code. This function computes the eigenvalues and eigenvectors of a matrix using QL algorithm. for some reasons I can't use the eig function's result in matlab. The obtained eigenvalues from this…
maryam yousefi
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Eigenvector and Eigenvalue of 8 X 8 matrix

I have a 8 x 8 matrix of floating point numbers and need to calculate eigenvector and eigenvalue from it. This is for feature reduction using PCA (Principal Component Analysis) and is one hell of a time consuming job if done by traditional methods.…
Sujan
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python finding eigen values and eigen vectors

I have a graph laplacian, for which I need to find out the largest 'k' eigen values and eigen vectors. I am using something like this :- #L= laplacian matrix. eigVal,eigVectors = eigsh(L, k, which='LA') This is giving me approximately correct…
Nihar Sarangi
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Calculating Eigenvectors and Eigenvalues for Principal Component Analysis

I am trying to perform a Principal Component Analysis of some 3D scans however I am stuck when calculating and working with the eigenvalues and eigenvectors. The scans are in a .obj file format. x y z v 0.001888 -0.058120…
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M = [A, B; -B, A] where A is pxp symmetric pd and B is pxp skew-symmetric. When is M pd?

Let M = [A, B; -B, A] be a 2p x 2p matrix where A is p x p symmetric positive definite (pd) real valued matrix and B is a p x p real valued skew-symmetric matrix. Also, the matrix A+iB is pd. Is the Matrix M always a pd? If not, under what…
Sarbojit Roy
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trying to return same eigen values and vectors results from numpy linalg eig as matlab eig does

I am trying to convert MATLABs eig function into python. I am trying to return the same results as MATLABs eig does in python, and I am using numpy.linalg.eig to try and do this, but it won't return the same values & vectors. I am currently using…
Peadar O Donnell
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Is there a way to generate a matrix in R with at least some negative eigenvalues?

I want to generate a matrix with at least some negative eigenvalues? I am attempting to use the spectral decomposition of a matrix to do so but it does not guarantee at least one negative eigenvalue
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Finding the common eigenvectors of two matrices

I want to find the common eigenvectors of two symmetric matrices with the same dimension in R Assuming two matrices L1 and L2 I am looking for vector X such that L1*X = (landa)L2*X where landa is the eigen value
Neelou
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How to calculate eigen vectors in matlab without eig

I have a matrix, I need to get the eigenvectors. I already calculated the eigenvalues, Let's assume we have the eigenvalues, I wrote this for i = 1:length(c) syms y cal_vec = (c-eig_Val(i)*I)*y == 0; eigVec(:,i) =…
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Program returns Incorrect eigenvalues

The set of eigenvalues_new1 of (matnew1) and eigenvalues_new2 of (matnew2) should give the square of the set of eigenvalues of (mat).. But in this code I am getting negative eigenvalues for matnew1 and matnew2.. Above all the square…
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How to implement this EigenVector Python Code in Java

I have found the right result of an Algorithm. Can I implement this code in Java? import numpy as np from scipy.linalg import eig transition_mat = np.matrix([ [0.8, 0.15,0.05 ],\ [0.075,0.85,0.075],\ [0.05, 0.15,0.8 ]]) S, U =…
Fascal
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