IBM Parallel ESSL is a scalable mathematical subroutine library that supports parallel processing applications.

Release 4.2 offers Parallel ESSL MPICH2 libraries ( Linux only) for use with the IBM Parallel Environment (IBM PE) Runtime Edition MPICH2 library. Release 4.2 also includes the following new ScaLAPACK subroutines:

• PDLANTR/PZLANTR - Triangular or Trapezoidal Matrix Norms
• PZPBTRF/PZPBTRS/PZPBSV - Positive Definite Complex Hermitian Band Matrix Factor/Solve/Combined Factor and Solve
• PZPTTRF/PZPTTRS/PZPTSV - Positive Definite Complex  Hermitian Tridiagonal Matrix Factor/Solve/Combined Factor and Solve
• PDSYEV/PZHEEV - All Eigenvalues, and Optionally the Eigenvectors, of a Real Symmetric or Complex Hermitian Matrix
• PZHEEVD - All Eigenvalues and Eigenvectors of a Complex Hermitian Matrix using a Parallel Divide-and-Conquer Algorithm

Find out more here.