Matrix Overlap Type#

Matrix overlap type = {standard | symmetric}

Description / Usage#

This card selects the kind of matrix overlap that occurs (for parallel computations). Valid options are:


The local processor considers only its own estimate for any unknown; results from adjacent processors are ignored. This is the default.


The local processor adds its own estimate together with estimates from adjacent processors, retaining symmetry of preconditioners if a symmetric technique is being employed.

If the Matrix ovelap type card is omitted, the default is standard.


Following is a sample card:

Matrix overlap type= symmetric

Technical Discussion#

This optional card determines how overlapping subdomain solver results are combined when different processors derive different estimates for the same solution unknown.

This overlap option is moot for serial problems whose data decomposition is trivial.