Staggered methodΒΆ

The staggered grid approach is a hierarchical one. In a first step the work of all domains sharing the same cartesian coordinate with respect to the highest dimension (z in three dimensions) is collected. Then, like in the TENSOR strategy the layer width in this dimension is adjusted based on comparison of the collected work with the collected work of the neighboring domains in the same dimension. As a second step each of these planes is divided into a set of columns, where all domains share the same cartesian coordinate in the next lower dimension (y in three dimensions). For each of these columns the before described procedure is repeated, i.e. work collected and the width of the columns adjusted accordingly. Finally, in the last step the work of individual domains is compared to direct neighbors and the width in the last dimension (x in three dimensions) adjusted. This leads to a staggered grid, that is much better suited to describe inhomogeneous work distributions than the TENSOR strategy.

Required number of vertices

  • two, one describing the lower left front point and one describing the upper right back point of the domain

Advantages

  • very good equalization results for the work load

  • maintains orthogonal domains

Disadvantages

  • changes topology of the domains and requires adjustment of neighbor relations

  • communication pattern in the calling code might require adjustment to deal with changing neighbors