Data Structures and Classes

In this chapter we illustrate the data structures used for definition of routines interfaces. They include data structures for sparse matrices, communication descriptors and preconditioners.

All the data types and the basic subroutine interfaces related to descriptors and sparse matrices are defined in the module psb_base_mod; this will have to be included by every user subroutine that makes use of the library. The preconditioners are defined in the module psb_prec_mod

Integer, real and complex data types are parametrized with a kind type defined in the library as follows:

psb_spk_

Kind parameter for short precision real and complex data; corresponds to a REAL declaration and is normally 4 bytes;

psb_dpk_

Kind parameter for long precision real and complex data; corresponds to a DOUBLE PRECISION declaration and is normally 8 bytes;

psb_mpk_

Kind parameter for 4-bytes integer data, as is always used by MPI;

psb_epk_

Kind parameter for 8-bytes integer data, as is always used by the sizeof methods;

psb_ipk_

Kind parameter for “local” integer indices and data; with default build options this is a 4 bytes integer;

psb_lpk_

Kind parameter for “global” integer indices and data; with default build options this is an 8 bytes integer;

The integer kinds for local and global indices can be chosen at configure time to hold 4 or 8 bytes, with the global indices at least as large as the local ones. Together with the classes attributes we also discuss their methods. Most methods detailed here only act on the local variable, i.e. their action is purely local and asynchronous unless otherwise stated. The list of methods here is not completely exhaustive; many methods, especially those that alter the contents of the various objects, are usually not needed by the end-user, and therefore are described in the developer's documentation.