Description:

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.