Introduction - If you have any usage issues, please Google them yourself
IRBLEIGS: Finds a few eigenvalues and eigenvectors of a Hermitian matrix.
IRBLEIGS will find a few eigenvalues and eigenvectors for either the standard eigenvalue problem A*x = lambda*x or the generalized eigenvalue problem A*x = lambda*M*x, where A is a sparse Hermitian matrix and the matrix M is positive definite.