Estimation
Interface
The interface that has to be implemented for an estimator.
ComputableDAGs.AbstractEstimator — TypeAbstractEstimatorAbstract base type for an estimator. An estimator estimates the cost of a graph or the difference an operation applied to a graph will make to its cost.
Interface functions are
ComputableDAGs.cost_type — Functioncost_type(estimator::AbstractEstimator)Interface function returning a specific estimator's cost type, i.e., the type returned by its implementation of graph_cost and operation_effect.
ComputableDAGs.graph_cost — Functiongraph_cost(estimator::AbstractEstimator, graph::DAG)Get the total estimated cost of the graph. The cost's data type can be chosen by the implementation, but must have a usable lessthan comparison operator (<), basic math operators (+, -) and an implementation of zero() and typemax().
ComputableDAGs.operation_effect — Methodoperation_effect(estimator::AbstractEstimator, graph::DAG, operation::Operation)Get the estimated effect on the cost of the graph, such that graph_cost(estimator, graph) + operation_effect(estimator, graph, operation) ~= graph_cost(estimator, graph_with_operation_applied). There is no hard requirement for this, but the better the estimate, the better an optimization algorithm will be.
There is a default implementation of this function, applying the operation, calling graph_cost, then popping the operation again.
It can be much faster to overload this function for a specific estimator and directly compute the effects from the operation if possible.
Global Metric Estimator
Implementation of a global metric estimator. It uses the graph properties compute effort, data transfer, and compute intensity.
ComputableDAGs.CDCost — TypeCDCost
Representation of a DAG's cost as estimated by the GlobalMetricEstimator.
Fields:
.data: The total data transfer..computeEffort: The total compute effort..computeIntensity: The compute intensity, will always equal .computeEffort / .data.
Note that the computeIntensity doesn't necessarily make sense in the context of only operation costs. It will still work as intended when adding/subtracting to/from a graph_cost estimate.
ComputableDAGs.GlobalMetricEstimator — TypeGlobalMetricEstimator <: AbstractEstimatorA simple estimator that adds up each node's set compute_effort and data.