Guide and Reference

What's New For Parallel ESSL

This section summarizes the changes made to each release of Parallel ESSL.

What's New for Parallel ESSL Version 2.1

• Parallel ESSL provides two new run-time libraries:

  • The Parallel ESSL SMP Library is provided for use with the Parallel ESSL message passing subroutines and the PE MPI threaded library. You may run single or multithreaded applications on all types of nodes. However, you cannot simultaneously call Parallel ESSL from multiple threads. Use this library if you are using both Parallel Environment (PE) Message Passing Interface (MPI) and the Communications Low-level Application Programming Interface (LAPI). The SMP library is for use on RS/6000* POWER* and PowerPC* (for example, 604 or 604e High Nodes) processors.

  • The Parallel ESSL Thread-Tolerant POWER2 Library is provided for use with the Parallel ESSL message passing subroutines and the PE MPI threaded library. You may run single or multithreaded applications on POWER2 nodes. However, you cannot simultaneously call Parallel ESSL from multiple threads. Use this library if you are using both PE MPI and LAPI. The Thread-Tolerant POWER2 library is tuned for the RS/6000 POWER2* processors.

• The Linear Algebraic Equations Subroutines now include iterative solutions to linear systems of equations for real general sparse matrices.

• The Fourier Transforms subroutines have had the transform length restriction removed. The transform lengths in each direction no longer need to be divisible by the number of processes.

• Parallel ESSL supports an environment variable, PESSL_ERROR_SYNC, which allows you to disable error synchronization. This may improve performance of production level codes.

• Format of array descriptors

  Migration Note
  If you are using the Message Passing Level 2 or 3 PBLAS, Linear Algebraic Equations, or the Eigensystem Analysis and Singular Value Analysis subroutines, you must now use the array descriptors defined in "Migrating Your Program" for your programs to continue to run with Parallel ESSL Version 2.

  The format of the array descriptors was changed in Parallel ESSL Version 1.2.1 to maintain compatibility with ScaLAPACK. Therefore, all application programs previously migrated to accommodate the new array descriptor, can run unchanged with Parallel ESSL Version 2.1 However, if you were dependent upon the PESSL_DESC_TYPE environment variable, you must change the array descriptors as defined in "Migrating Your Program". If you do not change the array descriptors, Parallel ESSL Version 2.1 issues an error message and terminates your program.

• The files for the Hypertext Markup Language (HTML) version of the Parallel ESSL Version 2 Guide and Reference are packaged with the Parallel ESSL product.