public void Build(MetricDB DB, double alpha_stddev, int min_bs, int seed)
{
DynamicSequential idxDynamic;
idxDynamic = new DynamicSequential (seed);
idxDynamic.Build (DB);
this.pivots_list = new List<int>();
this.pivots_idx = new int[DB.Count];
this.pivots_dist = new float[DB.Count];
// PivotGroup g = new PivotGroup(DB.Count);
//Console.WriteLine ("Number of objects: {0}",idxDynamic.DOCS.Count);
int I = 0;
while(idxDynamic.DOCS.Count > 0){
var pidx = idxDynamic.GetRandom();
object piv = DB[pidx];
idxDynamic.Remove(pidx);
this.pivots_list.Add(pidx);
this.pivots_dist[pidx] = 0;
this.pivots_idx[pidx] = pidx;
double mean, stddev;
IResult near, far;
idxDynamic.SearchExtremesRange(piv, alpha_stddev, min_bs, out near, out far, out mean, out stddev);
foreach (var pair in near){
this.pivots_idx[pair.docid] = pidx;
this.pivots_dist[pair.docid] = (float)pair.dist;
}
foreach (var pair in far){
this.pivots_idx[pair.docid] = pidx;
this.pivots_dist[pair.docid] = (float)-pair.dist;
}
if (I % 10 == 0) {
Console.WriteLine("--- I {0}> remains: {1}, alpha_stddev: {2}, mean: {3}, stddev: {4}, pivot: {5}",
I, idxDynamic.DOCS.Count, alpha_stddev, mean, stddev, pidx);
double near_first, near_last, far_first, far_last;
if (near.Count == 0) {
near_first = -1;
near_last = -1;
} else {
near_first = near.First.dist;
near_last = near.Last.dist;
}
if (far.Count == 0) {
far_last = far_first = -1;
} else {
far_first = -far.Last.dist;
far_last = -far.First.dist;
}
Console.WriteLine("--- +++ first-near: {0}, last-near: {1}, first-far: {2}, last-far: {3}, near-count: {4}, far-count: {5}",
near_first, near_last, far_first, far_last, near.Count, far.Count);
Console.WriteLine("--- +++ normalized first-near: {0}, last-near: {1}, first-far: {2}, last-far: {3}, mean: {4}, stddev: {5}",
near_first/far_last, near_last/far_last, far_first/far_last, far_last/far_last, mean/far_last, stddev/far_last);
//}
}
++I;
idxDynamic.Remove(near);
idxDynamic.Remove(far);
//Console.WriteLine("Number of objects after: {0}",idxDynamic.DOCS.Count);
}
Console.WriteLine("Number of pivots per group: {0}", this.pivots_list.Count);
}
protected override void SearchExtremes(DynamicSequential idx, List<ItemPair> items, object piv, double quantile, int min_bs, out IResult near, out IResult far, out DynamicSequential.Stats stats)
{
items.Clear();
idx.ComputeDistances (piv, items, out stats);
DynamicSequential.SortByDistance(items);
var n = idx.Count;
min_bs = Math.Max ((int)(quantile * n), min_bs);
near = new Result (min_bs);
far = new Result (min_bs);
idx.AppendKExtremes(near, far, items);
}
protected override void SearchExtremes(DynamicSequential idx, List<ItemPair> items, object piv, double alpha_stddev, int min_bs, out IResult near, out IResult far, out DynamicSequential.Stats stats)
{
items.Clear();
idx.ComputeDistances (piv, items, out stats);
// var radius = stats.min; // stats.stddev * alpha_stddev;
near = new Result (min_bs);
far = new Result (min_bs);
// idx.DropCloseToMean (stats.mean - radius, stats.mean + radius, near, far, items);
// if (near.Count == 0 && far.Count == 0 & min_bs > 0) {
idx.AppendKExtremes(near, far, items);
// }
}
protected virtual void SearchExtremes(DynamicSequential idx, List<ItemPair> items, object piv, double alpha_stddev, int min_bs, out IResult near, out IResult far, out DynamicSequential.Stats stats)
{
throw new NotSupportedException();
}
