public bool Equals(GroupByState <V> that)
{
if (this.elements.Count != that.elements.Count)
{
return(false);
}
for (int i = 0; i < elements.Count; i++)
{
if (!elements.Array[i].Equals(that.elements.Array[i]))
{
return(false);
}
}
return(true);
}
protected override GroupByState <V> UpdateState(K key, GroupByState <V> state, int updateRootIndex)
{
if (state.elements.Array == null)
{
state.elements = new ResizeableSubArray <Weighted <V> >(0);
}
updateAccumulator.Clear();
resultAccumulator.Clear();
// first determine and subtract the previous outputs
groupContent.Clear();
for (int i = 0; i < state.elements.Count; i++)
{
// set the weight associated with this record
updateAccumulator[state.elements.Array[i].record] = state.elements.Array[i].weight;
// add the element to the materialized list
groupContent.Add(state.elements.Array[i].record);
var weight = (state.elements.Array[i].weight - (i == state.elements.Count - 1 ? 0 : state.elements.Array[i + 1].weight)) / 2;
if (weight != 0)
{
var result = resultSelector(key, groupContent);
if (!resultAccumulator.ContainsKey(result))
{
resultAccumulator.Add(result, 0);
}
resultAccumulator[result] -= weight;
}
}
// update the accumulation based on the updates we see.
for (int index = updateRootIndex; index >= 0; index = updateChain[index].previous)
{
var selected = selector(updateChain[index].update.record);
if (!updateAccumulator.ContainsKey(selected))
{
updateAccumulator.Add(selected, 0);
}
updateAccumulator[selected] += updateChain[index].update.weight;
}
// load the new accumulation into state
state.elements.Clear();
foreach (var pair in updateAccumulator.OrderByDescending(x => x.Value))
{
if (pair.Value > 0)
{
state.elements.Add(new Weighted <V>(pair.Key, pair.Value));
}
if (pair.Value < 0)
{
Console.Error.WriteLine("Negative accumulation in GroupBy; probably a bug somewhere");
}
}
// second determine and add the current outputs
groupContent.Clear();
for (int i = 0; i < state.elements.Count; i++)
{
// add the element to the materialized list
groupContent.Add(state.elements.Array[i].record);
var weight = (state.elements.Array[i].weight - (i == state.elements.Count - 1 ? 0 : state.elements.Array[i + 1].weight)) / 2;
if (weight != 0)
{
var result = resultSelector(key, groupContent);
if (!resultAccumulator.ContainsKey(result))
{
resultAccumulator.Add(result, 0);
}
// subtract half the difference to the next weight, with zero for the last weight
resultAccumulator[result] += weight;
}
}
foreach (var pair in resultAccumulator)
{
if (pair.Value != 0)
{
Send(new Weighted <R>(pair.Key, pair.Value));
}
}
return(state);
}
