This chapter explains how to migrate your application programs to Parallel ESSL Version 2.1.
This section explains how to update your message passing application programs when migrating from an earlier release to Parallel ESSL Version 2.1.
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 described in "Array Descriptor Considerations".
Subroutines with the option of dynamic allocation have been updated to be consistent with ScaLAPACK 1.5. You do not need to update your application programs unless you choose to exploit the new capability.
The message-passing and HPF tridiagonal subroutines have been updated to be consistent with ScaLAPACK 1.5. If Parallel ESSL detects a computational error, the value returned in info is the process number where the error occurred. Previously, the index of the pivot where the matrix failed was returned in info. For the message-passing tridiagonal subroutines, the scope of info is now global. You do not have to make any modifications to your existing programs that call these subroutines. See the subroutines descriptions for specific details.
HPF application programs that run using Parallel ESSL Version 1.2 can be run unchanged using Parallel ESSL Version 2.1.
When using Parallel ESSL, you must code your new application programs using the array descriptors described in "Distributing Your Data". Also, if you were dependent upon the PESSL_DESC_TYPE environment variable, you must update any existing application programs to use the array descriptors described in "Distributing Your Data".
For more details on the array descriptors and how they are used for data distribution, see "Specifying and Distributing Data in a Message Passing Program".
A field DTYPE_ is at location 1, and the CTXT_ field, previously at location 7, is moved to location 2. This causes all other fields to move down one or more locations in the array descriptor. The format of the array descriptor is shown in Table 16.
The field at location 1 is renamed DTYPE_, and the CTXT_ field, previously at location 5, is moved to location 2. This causes some of the fields to move down one location in the array descriptor. The format of the array descriptors is shown in Table 21 and Table 22.
To minimize coding changes in the future, due to changes in the array descriptors, consider referencing the fields in the array descriptors symbolically in your program. For an example of this technique, see the Message Passing sample program in Appendix B. "Sample Programs".