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Andrew Knyazev


Last seen: 11 days ago Active since 2010

http://en.wikipedia.org/wiki/Andrei_Knyazev_(mathematician)

Professional Interests: matrix computations, numerical PDEs, signal, image & video processing, data analytics and mining, data coding and transmission, material sciences, and model predictive control.

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Answered
Eigs in multinode cluster
EIGS has limited support for distributed memory, so you can run it only on a single node, but see the answer from Christine Tob...

2 years ago | 0

| accepted

Answered
How do read .npy files in matlab?
https://github.com/kwikteam/npy-matlab

2 years ago | 8

| accepted

Answered
Error returned in Eigs Function " Undefined operator '.*' "
Looks like a bug in chebfun - just make this comment at <https://www.mathworks.com/matlabcentral/fileexchange/47023-chebfun-curr...

3 years ago | 0

Answered
eigs does not return the eigenvalues closest to shift sigma
You may also want to try https://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m passing your function handle to it. Co...

3 years ago | 0

Answered
find eigenvalues of a very large sparse matrix
If the matrix is real symmetric or Hermitian, you may also want to try https://www.mathworks.com/matlabcentral/fileexchange/48-l...

3 years ago | 0

Answered
LOBPCG Initial k eigenvectors approximation
See https://en.wikipedia.org/wiki/LOBPCG#Convergence_theory_and_practice

3 years ago | 0

Answered
eigs() runs faster for more eigenvalues of the same matrix
Please check <https://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m> that has probably faster and more predictable co...

3 years ago | 1

Answered
How do i obtain only the first principal component?
https://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m can be used as the method for calculating the eigenvector corre...

3 years ago | 0

Answered
Smallest non-zero eigenvalue for a generalized eigenvalue problem
Since both matrices A and B are singular, it is not an easy problem numerically. Even eig(full(A), full(B)) may give you wrong a...

3 years ago | 0

| accepted

Answered
Find max/min eigenvalue of a symmetric matrix
try http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 1

Answered
Number of eigenvalues when using eigs
This is normal for eigs.

6 years ago | 0

Answered
positive-definiteness of a huge sparse matrix
try http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 0

Answered
how can i find k-eigenvalues faster than eig for hermitian dense matrix
try http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 0

Answered
Take advantage of Hermitian matrices with eigs
You need to be more specific. Also, try http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 0

| accepted

Answered
Parallel computing of eigs
check SLEPc and BLOPEX

6 years ago | 0

Answered
Sparse solver for large symmetric matrices
both eigs and http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m can be used in a matrix-free fashion, only needing...

6 years ago | 0

Answered
Difference between eigs and eig
Is this behavior expected? - Yes. Eigs uses a tricky method that may give the results you describe, especially for funny mat...

6 years ago | 0

Answered
eigs function: incorrect eigenvectors
This is normal for eigs. If you are happy with eig, just stay with it.

6 years ago | 0

Answered
Why can't I compute the interior eigenvalues of a sparse matrix with "eigs" without inversion in MATLAB?
check https://www.mathworks.com/matlabcentral/fileexchange/48-locally-optimal-block-preconditioned-conjugate-gradient

6 years ago | 0

Answered
How can I get the (approximate) eigenvectors of a huge matrix?
try http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 0

Answered
How can I speed up the eigen value and eigen vector computations for a non-sparse matrix?
check http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 0

Answered
How can the Cholesky decomposition step in eigs() be avoided without passing a matrix to eigs that is a Cholesky decomposition?
check http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m

6 years ago | 0

Answered
eigs with sparse matrices
try my http://www.mathworks.com/matlabcentral/fileexchange/48-lobpcg-m instead

10 years ago | 0

Answered
Memory requirements of lobpcg: Matlab and hypre implementation differences
Have you actually tried the development version of SLEPc? The one that one gets by svn checkout http://www.grycap.upv.es/sle...

10 years ago | 0

Answered
Memory requirements of lobpcg: Matlab and hypre implementation differences
The development version of SLEPc incorporates BLOPEX now, see http://code.google.com/p/blopex/wiki/PETScInstallDevel so that yo...

10 years ago | 0

Answered
Memory requirements of lobpcg: Matlab and hypre implementation differences
Please try adding the following options to the ij driver: "-hmis -agg_nl 1 -interptype 6 -Pmx 4" These are proposed by a member ...

10 years ago | 0

Answered
Memory requirements of lobpcg: Matlab and hypre implementation differences
The lobpcg code in hypre is very similar to the MATLAB code, and uses about the same memory. The BoomerAMG preconditioner requir...

10 years ago | 0

| accepted

Answered
lobpcg returning incorrect results for large sparse symmetric matrices
Very slow convergence is an expected normal behavior of lobpcg for such a problem, without preconditioning. Unfortunately, I am ...

10 years ago | 1

| accepted