Stack Overflow
Stack Overflow

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.

Find more on this topic on Wikipedia

747 questions
0
votes
2 answers

How to create matrix from set of lists which contains more than 4 values?

I have set of lists (i.e. list x , list y, list z), e.g. x = ['41.95915452', '41.96333025', '41.98135503', '41.95096716', '41.96504172', '41.96526867', '41.98068483', '41.98117072', '41.98059828', '41.95915452', '41.96333025', '41.98135503',…
A_learner
  • 47
  • 10
0
votes
1 answer

How to find the eigen value and eigen vector of matrix with size (5030 * 3 )?

I have to find the eigen values of matrix which contains the 5030 rows and 3 columns. while using the numpy.linalg.eig(matrix) function it gives me error of LinAlgError: Last 2 **dimensions** of the array must be square is it compulsory that for…
A_learner
  • 47
  • 10
0
votes
0 answers

Cholesky decomposition with Eigen

I am trying to apply Cholesky Decomposition on a symmetric, voluntarily non positive definite matrix, to see how the system behaves. The matrix I am analysing is a 3*3 matrix whose eigenvalues are: -29.5, 2, 30.5. Since there is a negative…
Tommaso Ferrari
  • 13
  • 1
0
votes
2 answers

Python: numpy.linalg.linalgerror: last 2 dimensions of the array must be square

I have a matrix that gives out something like that: a = [[ 3.14333470e-02 3.11644303e-02 3.03622814e-02 2.90406252e-02 2.72220757e-02 2.49377488e-02 2.22267299e-02 1.91354055e-02 1.57166688e-02 1.20290155e-02 8.13554227e-03 …
Jolosin
  • 33
  • 1
  • 6
0
votes
2 answers

Strange behaviour using Arpack EigenLibrary Wrapper for small matrices

I want to solve the following generalized EVP using the ArpackWrapper of the Eigen library: K_e is SPD. Normally K_g is indefinite and singular but for this MVP it is just indefinite. Furthermore, I'm interested in the smallest eigenvalues. For…
rath3t
  • 101
  • 4
0
votes
1 answer

output results mismatch, LAPACKE_zheev() vs cusolverDnZheevd()

I am translating code from legacy cblas/lapacke to cudaBLAS/cudaSOLVER and having some issues. I made a test program to get into the bottom of this. Attached is the code that I am using: #include #include #include…
carbuet
  • 1
  • 1
0
votes
1 answer

counterintuitive speed difference between LM and shift-invert modes in scipy.sparse.linalg.eigsh?

I'm trying to find the smallest (as in most negative, not lowest magnitude) several eigenvalues of a list of sparse Hermitian matrices in Python using scipy.sparse.linalg.eigsh. The matrices are ~1000x1000, and the list length is ~500-2000. In…
lhk
  • 1
0
votes
0 answers

gvcsp in fortran 90

I want to fine eigenvalue and eigenvector of matrix that is symmetric positive definite define. However, I can not use function GVCSP in Fortran in Linux. Are there another function in Fortran that is equivalent GVCSP function. here is my…
PHuong
  • 11
  • 3
0
votes
0 answers

can i solve a non-linear eigen value problem with fsolve in python?

i have a an eigenvalue problem of non linear type c_0 + lambda*c_1 + lambda^2*c_2 + c_3*lambda^3=0 i've been trying by inversing the matrix of coefficients c, but is a singular matrix, it will create complex values. somebody sujeted me that i can…
jsp
  • 155
  • 1
  • 7
0
votes
1 answer

Incorrect eigenvalues with ZGEEV in LAPACK when repeated

I have the following code which finds the eigenvalues of a non-Hermitian complex matrix H. Program Eigen_nonHermitian implicit none integer:: Nstate,i double precision:: t,eps,tm,tp,U double complex:: H(6,6),E(6) double precision:: l !…
hbaromega
  • 2,317
  • 2
  • 24
  • 32
0
votes
1 answer

LAPACK dgeev function doesn't work in eigenvectors estimation

I have that code to calculate eigenvelues and eigenvectors in MEX with Lapack library: char *JOBVL="N"; char *JOBVR="V"; mwSignedIndex LDA, LDVL, LDVR, LWORK, INFO; LDA = dim; LDVL = dim; LDVR = dim; LWORK = 4*dim; double *Awork, *WR,…
jualsevi
  • 289
  • 1
  • 2
  • 8
0
votes
0 answers

Parallel method to get all the eigenvalues of a large sparse matrix

Is it possible to compute all the eigenvalues of a large sparse matrix using multiple CPUs ? If yes, then is it possible to do it without storing the full dense matrix in memory ? (using only the stored sparse matrix) If yes, then what's a good…
Gab
  • 71
  • 1
  • 9
0
votes
2 answers

Finding corresponding eigenvalues to a set of eigenvector

I solved most of this assignment using Python, but not sure how to input (or even understand) the remaining information. Aren't you supposed to find the eigenvector given some eigenvalue, thus it appears in reverse in the following: Let the…
Saurus
  • 79
  • 1
  • 7
0
votes
1 answer

Negative and complex number eigenvalues for PCA

I have produced a correlation matrix my_corr = rtn.corr(method = 'pearson') and I did the PCA composition on that matrix from scipy : eig_vals, eig_vecs = linalg.eig(my_corr). However I get negative and complex number for eigen values…
lei gu
  • 31
  • 2
0
votes
1 answer

Autoencoders: Find the important neurons

I have implemented Autoencoder using Keras that takes 112*112*3 neurons as input and 100 neurons as the compressed/encoded state. I want to find the neurons out of these 100 that learns the important features. So far i have calculated eigen…
farmillion123
  • 179
  • 1
  • 12
1 2 3
…
49 50