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Aggregate Plan

Aggregation Tree

AggregatePlan describes the upward aggregation traversal on a tree. It specifies:

  • which nodes are visited per level during aggregation,
  • which node moments must be stored for later phases, and

This is a non-translating aggregation plan. Its counterpart for a matrix-vector product is DisaggregateTranslatePlan.

Building an AggregatePlan

Conceptually, AggregatePlan is built from a tree and a function aggregatenode(node).

  • If aggregatenode(node) is true, that node is marked for storage.
  • If not, the node is still included in traversal when one of its ancestors is a storing node.
  • Aggregation levels are organized from leaves toward the root.

This ensures aggregation paths remain complete for all moments that must be available later.

Fields

An AggregatePlan stores:

  • nodes: aggregation nodes grouped by level.
  • levels: aggregation levels, ordered leaves-to-root.
  • storenode: booleans indicating which node moments are stored.
  • rootoffset: offset used to convert node ids to compact 1-based indices.
  • tree: the tree associated with the plan.

Example

The example below constructs Galerkin plans in AggregateMode() and extracts the trial-side AggregatePlan.

plans = H2Trees.galerkinplans(tree, aggregatenode, tfiterator, H2Trees.AggregateMode())
aggregateplan = plans.trialaggregationplan
aggregateplan
AggregatePlan{TwoNTree{3, BoxData{3, Float64}, Float64}}([[11, 12, 13, 14, 15, 16, 17, 20, 21, 22  …  792, 793, 794, 798, 799, 800, 801, 802, 803, 804], [5, 6, 7, 8, 9, 10, 19, 27, 28, 35  …  778, 779, 786, 787, 796, 797, 805, 806, 807, 808], [3, 4, 18, 37, 51, 66, 72, 76, 80, 101  …  662, 676, 695, 710, 724, 743, 762, 776, 795, 809]], 5:-1:3, Bool[0, 0, 1, 1, 1, 1, 1, 1, 1, 1  …  1, 1, 1, 1, 1, 1, 1, 1, 1, 1], 0, TwoNTree{3, BoxData{3, Float64}, Float64}
 level: 1 with 1 node(s) with on average 18750.0 points and 8.0 children and halfsize: 0.9995217120782627
- level: 2 with 8 node(s) with on average 2343.75 points and 7.0 children and halfsize: 0.49976085603913134
-- level: 3 with 56 node(s) with on average 334.82 points and 4.71 children and halfsize: 0.24988042801956567
--- level: 4 with 264 node(s) with on average 69.39 points and 1.82 children and halfsize: 0.12494021400978284
---- level: 5 with 480 node(s) with on average 16.59 points and 0.0 children and halfsize: 0.06247010700489142
)