private void CalculateAggregate(AggregateKey key)
{
ImmutableArray <Int32> columnMapping = ColumnDependencyMappings[key];
ImmutableArray <Int32> aggregateMapping = AggregateDependencyMappings[key];
AggregateValueBag aggregateBag = new AggregateValueBag(AggregateRow, aggregateMapping);
Aggregate <TInput> aggregate = Aggregates[key];
Int32 aggregateIndex = AggregateIndexes[key];
AggregateRow[aggregateIndex] = aggregate.Calculate(aggregateBag, Rows.Select(row => new ColumnValueBag <TInput>(row, columnMapping)));
}
protected Aggregate(AggregateKey key, ImmutableArray <ColumnKey> columnDependencies, ImmutableArray <AggregateKey> aggregateDependencies)
{
Key = key ?? throw new ArgumentNullException(nameof(key));
ColumnDependencies = columnDependencies;
AggregateDependencies = aggregateDependencies;
}