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psb_cdbldext -- Build an extended communication descriptor

call psb_cdbldext(a,desc_a,nl,desc_out, info, extype)

This subroutine builds an extended communication descriptor, based on the input descriptor desc_a and on the stencil specified through the input sparse matrix a.

Type:
Synchronous.
On Entry
a
A sparse matrix Scope:local.
Type:required.
Intent: in.
Specified as: a structured data type.
desc_a
the communication descriptor.
Scope:local.
Type:required.
Intent: in.
Specified as: a structured data of type spdatapsb_Tspmat_type.
nl
the number of additional layers desired.
Scope:global.
Type:required.
Intent: in.
Specified as: an integer value $nl\ge 0$.
extype
the kind of estension required.
Scope:global.
Type:optional .
Intent: in.
Specified as: an integer value psb_ovt_xhal_, psb_ovt_asov_, default: psb_ovt_xhal_

On Return
desc_out
the extended communication descriptor.
Scope:local.
Type:required.
Intent: inout.
Specified as: a structured data of type descdatapsb_desc_type.
info
Error code.
Scope: local
Type: required
Intent: out.
An integer value; 0 means no error has been detected.

Notes

  1. Specifying psb_ovt_xhal_ for the extype argument the user will obtain a descriptor for a domain partition in which the additional layers are fetched as part of an (extended) halo; however the index-to-process mapping is identical to that of the base descriptor;
  2. Specifying psb_ovt_asov_ for the extype argument the user will obtain a descriptor with an overlapped decomposition: the additional layer is aggregated to the local subdomain (and thus is an overlap), and a new halo extending beyond the last additional layer is formed.


next up previous contents
Next: psb_spall Allocates Up: Data management routines Previous: psb_cdfree Frees   Contents