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Diffstat (limited to 'math/arpack/DESCR')
| -rw-r--r-- | math/arpack/DESCR | 58 |
1 files changed, 23 insertions, 35 deletions
diff --git a/math/arpack/DESCR b/math/arpack/DESCR index ded552c3db2..3205bcda348 100644 --- a/math/arpack/DESCR +++ b/math/arpack/DESCR @@ -1,35 +1,23 @@ -ARPACK is a collection of Fortran77 subroutines designed to solve large -scale eigenvalue problems. - -The package is designed to compute a few eigenvalues and corresponding -eigenvectors of a general n by n matrix A. It is most appropriate for large -sparse or structured matrices A where structured means that a matrix-vector -product w <- Av requires order n rather than the usual order n**2 floating -point operations. This software is based upon an algorithmic variant of the -Arnoldi process called the Implicitly Restarted Arnoldi Method (IRAM). When -the matrix A is symmetric it reduces to a variant of the Lanczos process -called the Implicitly Restarted Lanczos Method (IRLM). These variants may be -viewed as a synthesis of the Arnoldi/Lanczos process with the Implicitly -Shifted QR technique that is suitable for large scale problems. For many -standard problems, a matrix factorization is not required. Only the action -of the matrix on a vector is needed. ARPACK software is capable of solving -large scale symmetric, nonsymmetric, and generalized eigenproblems from -significant application areas. The software is designed to compute a few (k) -eigenvalues with user specified features such as those of largest real part -or largest magnitude. Storage requirements are on the order of n*k locations. -No auxiliary storage is required. A set of Schur basis vectors for the desired -k-dimensional eigen-space is computed which is numerically orthogonal to working -precision. Numerically accurate eigenvectors are available on request. - -Important Features: - - o Reverse Communication Interface. - o Single and Double Precision Real Arithmetic Versions for Symmetric, - Non-symmetric, Standard or Generalized Problems. - o Single and Double Precision Complex Arithmetic Versions for Standard - or Generalized Problems. - o Routines for Banded Matrices - Standard or Generalized Problems. - o Routines for The Singular Value Decomposition. - o Example driver routines that may be used as templates to implement - numerous Shift-Invert strategies for all problem types, data types - and precision. +ARPACK is a collection of Fortran77 subroutines designed to solve large scale +eigenvalue problems. The package is designed to compute a few eigenvalues and +corresponding eigenvectors of a general n by n matrix A. It is most appropriate +for large sparse or structured matrices A where structured means that a +matrix-vector product w <- Av requires order n rather than the usual order n**2 +floating point operations. This software is based upon an algorithmic variant of +the Arnoldi process called the Implicitly Restarted Arnoldi Method (IRAM). When +the matrix A is symmetric it reduces to a variant of the Lanczos process called +the Implicitly Restarted Lanczos Method (IRLM). These variants may be viewed as +a synthesis of the Arnoldi/Lanczos process with the Implicitly Shifted QR +technique that is suitable for large scale problems. For many standard problems, +a matrix factorization is not required. Only the action of the matrix on a +vector is needed. ARPACK software is capable of solving large scale symmetric, +nonsymmetric, and generalized eigenproblems from significant application areas. +The software is designed to compute a few (k) eigenvalues with user specified +features such as those of largest real part or largest magnitude. Storage +requirements are on the order of n*k locations. No auxiliary storage is +required. A set of Schur basis vectors for the desired k-dimensional eigen-space +is computed which is numerically orthogonal to working precision. Numerically accurate eigenvectors are available on request. Important Features: + o Reverse Communication Interface. + o Single and Double Precision Real Arithmetic Versions for Symmetric, + Non-symmetric, Standard or Generalized Problems. + ...and more! |