PeIGS parallel eigensolver library. The PeIGS library contains subroutines for solving standard and generalized real symmetric eigensystems. All eigenvalues and eigenvectors can be computed. PeIGS incorporates scalable: data structures: compact storage, column distribution with panel-block computation; and algorithms including inverse iteration with repeated reorthogonalization. The library is implemented using message-passing model and is portable across many platforms.