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Questions tagged [arpack]

ARPACK is a package for solving large scale eigen value problems. Question tagged arpack relate to usage of this library, linking with it and compiling code using its subroutines.

ARPACK is a collection of Fortran77 subroutines designed to solve large scale eigenvalue problems.

For more information, see ARPACK's website

72 questions
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Address not passed properly to Fortran function call

I've been trying to find eigenvectors of a matrix by declaring ARPACK functions in C++ using extern "C": extern "C" {void znaupd_(int *IDO, char *BMAT, int *N, char *WHICH, int *NEV, double *TOL, complex *RESID, …
user2794250
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Scipy arpack eigs versus eigsh number of eigenvalues

In scipy's ARPACK bindings, one cannot calculate all of the eigenvalues of a matrix. However, I find that eigsh is able to calculate n - 1 eigenvalues, while eigs is only able to calculate n - 2 eigenvalues. Can anyone verify that this is in fact…
user1973192
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Why doesn't scipy.sparse.linalg.eigs produce a correct subset of the eigenvalues in this problem?

I have an eigenvalue problem which I would like to solve using SciPy. In this problem it is strongly preferable to use an iterative solver which will return a subset of the (largest/smallest) eigenvalues. My matrix is complex and non-symmetric and…
astnstn
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Assigning Values to the Array ipntr in ARPACK

I am trying to figure out how values are assigned to the array called ipntr, which stores pointers, in ARPACK. I am relatively new to fortran and I can't figure out exactly how the values of this array are initially set. The code I am looking at is…
Colin
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Issue with finding eigenvalues with smallest magnitude using eigs

I have a large Hermitian sparse matrix, and I'd like to get a few of the eigenvalues with the smallest magnitude. I'm using the "eigs" function in Arpack however I get this error message: ZeroPivotException: factorization encountered one or more…
Ahmad Khalifa
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Compute eigenvalues of complex-hermitian sparsematrix in Julia

Im working with some roughly 100000x100000 hermitian complex sparse-matrices, with roughly 5% of entries populated, and want to calculate the eigenvalues/eigenvectors. Sofar ive been using Arpack.jl eigs(A). But this is not working well as soon as …
Jakob Sachs
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Usage of arpack-ng/openblas/javacpp in the smile java library

I'm trying to set up the Smile machine learning library in Java but I'm having some issues getting some dependencies to work. Currently I am on a Fedora machine, but I'd like this to work on any machine, just like a normal jar. Here is some example…
Jurian Baas
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CVXPY Quadratic Programming; ArpackNoConvergence error

I'm trying to use the Python package CVXPY to solve a convex quadratic programming problem of the first form here: https://www.cvxpy.org/examples/basic/quadratic_program.html, using the following code x = np.variable(2 * N) prob =…
Qwertiops
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All eigenvectors of large sparse matrices are zero

I have a 50,000 by 50,000 dense matrix or larger. If I use the numpy or scipy- packages the entries of all my eigenvectors are 0. If I use scipy.sparse to calculate just 1000-8000 eigenvectors, I get the right eigenvectos. But I need all of…
Python_Question
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DLL Load Failed for _arpack

Can't quite work around this error. Please any lead. from scipy.optimize import fsolve ImportError Traceback (most recent call last) in ----> 1 from scipy.optimize import…
Gabriel Soares
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Applying scipy.sparse.linalg.svds returns nan values

I am starting to use the scipy.sparse library, and when I try to apply scipy.sparse.linalg.svds, I get an error if there are zero singular values. I am doing this because in the end I am going to use very large and very sparse matrices with entries…
Amir
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Compute eigenvalues with Arpack

I am using Arpack to compute the eigenvalues of the problem \lambda Mx = Ax with reverse shift method with complex shift. Then, I use znaupd e zneupd. Everything seems to be ok. I wrote a function that takes the eigenvalues and the eigenvectors…
Britomarti
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Issues with makefiles when installing ARPACK

I'm currently trying to install ARPACK so that I can use sparse matrices in Armadillo for large information networks. The instructions for However, when I try running make lib after altering the directory the files are in, but I run into trouble…
Max Candocia
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Arpack(++) on windows

I'm trying to get Arpack and Arpack++ to work in Windows 7 with Visual Studio 2010, and use swig to make an interface that can be used with C#. This is basically to create a benchmark against which I will measure all further attempts at solving…
Arthur
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ARPACK page rank error

I'm using the igraph package in R to run PageRank. I ran it for my graph and got this error: At arpack.c:1130 : ARPACK error, The Schur form computed by LAPACK routine dlahqr could not be reordered by LAPACK routine dtrsen. I read online that this…
Xodarap
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