/// <summary>
/// Return true if we've only seen parent-sibling-separator combo as a split list.
/// Return true if we've seen that combo as both list and split list AND
/// len of all siblings is closer to split median than to regular nonsplit median.
/// </summary>
public virtual bool isOversizeList <T1>(ParserRuleContext ctx, IList <T1> siblings, Token separator) where T1 : Antlr4.Runtime.ParserRuleContext
{
ParserRuleContext first = siblings[0] as ParserRuleContext;
ParentSiblingListKey pair = new ParentSiblingListKey(ctx, first, separator.Type);
SiblingListStats stats = null;
corpus.rootAndChildListStats.TryGetValue(pair, out stats);
SiblingListStats splitStats = null;
corpus.rootAndSplitChildListStats.TryGetValue(pair, out splitStats);
bool oversize = stats == null && splitStats != null;
if (stats != null && splitStats == null)
{
// note: if we've never seen a split version of this ctx, do nothing;
// I used to have oversize failsafe
}
int len = Trainer.getSiblingsLength(siblings);
if (stats != null && splitStats != null)
{
// compare distance in units of standard deviations to regular or split means
// like a one-dimensional Mahalanobis distance.
// actually i took out the stddev divisor. they are usually very spread out and overlapping.
double distToSplit = Math.Abs(splitStats.median - len);
double distToSplitSquared = Math.Pow(distToSplit, 2);
double distToSplitStddevUnits = distToSplitSquared / Math.Sqrt(splitStats.variance);
double distToRegular = Math.Abs(stats.median - len);
double distToRegularSquared = Math.Pow(distToRegular, 2);
double distToRegularStddevUnits = distToRegularSquared / Math.Sqrt(stats.variance);
// consider a priori probabilities as well.
float n = splitStats.numSamples + stats.numSamples;
float probSplit = splitStats.numSamples / n;
float probRegular = stats.numSamples / n;
double adjDistToSplit = distToSplitSquared * (1 - probSplit); // make distance smaller if probSplit is high
double adjDistToRegular = distToRegularSquared * (1 - probRegular);
if (adjDistToSplit < adjDistToRegular)
{
oversize = true;
}
}
return(oversize);
}
public virtual IDictionary <ParentSiblingListKey, SiblingListStats> getListStats(IDictionary <ParentSiblingListKey, IList <int> > map)
{
IDictionary <ParentSiblingListKey, SiblingListStats> listSizes = new Dictionary <ParentSiblingListKey, SiblingListStats>();
foreach (ParentSiblingListKey pair in map.Keys)
{
IList <int> lens = map[pair];
var new_lens = lens.OrderBy(i => i).ToList();
lens = new_lens;
int n = lens.Count;
int? min = lens[0];
int? median = lens[n / 2];
int? max = lens[n - 1];
double @var = BuffUtils.variance(lens);
listSizes[pair] = new SiblingListStats(n, min.Value, median.Value, @var, max.Value);
}
return(listSizes);
}