public CostCounter ExactSearch(double[] ts, out IndexFileDist bsf)
{
CostCounter meas = new CostCounter(0, 0);
IntervalHeap <IndexEntryDist> pq = new IntervalHeap <IndexEntryDist>(NumIndexEntries);
// approx search
TermEntry approx = ApproximateSearch(ts);
bsf = Index <DATAFORMAT> .MinFileEucDist(ts, approx.FileName);
meas.IO++;
meas.distance += approx.NumTimeSeries;
// initalize pq with IndexEntries at root node
foreach (IndexEntry e in index.Values)
{
pq.Add(new IndexEntryDist(e, Sax.MinDistPAAToiSAX(
Sax.SaxStrToSaxVals(e.SaxWord), options.SaxOpts, ts)));
}
while (!pq.IsEmpty)
{
IndexEntryDist minInfo = pq.DeleteMin();
IndexEntry minEntry = minInfo.entry;
if (minInfo.dist >= bsf.distance)
{
break;
}
if (minEntry is TermEntry)
{
IndexFileDist posMin = Index <DATAFORMAT> .MinFileEucDist(ts, ((TermEntry)minEntry).FileName);
meas.IO++;
meas.distance += minEntry.NumTimeSeries;
// update bsf
if (posMin.distance < bsf.distance)
{
bsf = posMin;
}
}
else if (minEntry is SplitEntry <DATAFORMAT> )
{
SplitEntry <DATAFORMAT> sEntry = minEntry as SplitEntry <DATAFORMAT>;
foreach (IndexEntry e in sEntry.GetIndexEntries())
{
pq.Add(new IndexEntryDist(e, Sax.MinDistPAAToiSAX(
Sax.SaxStrToSaxVals(e.SaxWord), sEntry.Options.SaxOpts, ts)));
}
}
}
return(meas);
}
public static IndexFileDist MinFileEucDist(double[] ts, string file)
{
ushort[] val;
double[] dd;
byte[] temp;
int pos = 0;
int length;
IndexFileDist?best = null;
int lineNum = 1;
int wlen = Globals.SaxBaseCard;
using (FileStream sr = new FileStream(file, FileMode.Open, FileAccess.Read))
{
BinaryReader r = new BinaryReader(sr);
pos = 0;
length = (int)r.BaseStream.Length;
val = new ushort[wlen];
dd = new double[ts.Length];
while (pos < length)
{
temp = r.ReadBytes(SaxData.ByteLength(typeof(DATAFORMAT)));
SaxData tmp = SaxData.Parse <DATAFORMAT>(temp);
pos = pos + SaxData.ByteLength(typeof(DATAFORMAT));
double[] fileTs = Util.NormalizationHandler(tmp.dl.GetTimeSeries());
// repo.ReturnData(Util.IndexFlineToDataLocation(line)));
double dist = Util.EuclideanDistance(fileTs, ts);
IndexFileDist retEntry = new IndexFileDist(file, lineNum, dist);
if (best == null)
{
best = retEntry;
}
else
{
if (best.Value.distance > dist)
{
best = retEntry;
}
}
lineNum++;
}
r.Close();
sr.Close();
}
return(best.Value);
}
/// <summary>
/// Builds an index with randomly generated time series
/// </summary>
public static void BaseIndex()
{
DateTime startTime = DateTime.Now;
// index construction
Index <RawDataFormat> si = new Index <RawDataFormat>(0, new IndexOptions("root"));
DataLoader dl = new GeneratedRawDataLoader(si, Globals.TimeSeriesLength, NUM_TIMESERIES, SEED);
InsertTimeSeries(dl);
Console.WriteLine();
Console.WriteLine("Sequential Disk Accesses: " + DiskCost.seqcost);
Console.WriteLine("Random Disk Accesses: " + DiskCost.rancost);
Console.WriteLine("Read Disk Accesses: " + DiskCost.readcost);
Console.WriteLine("Saved cost in buffer: " + DiskCost.savedcost);
Console.WriteLine();
Index <RawDataFormat> .Save(Globals.IndexRootDir, si);
Index <RawDataFormat> si2 = Index <RawDataFormat> .Load(Globals.IndexRootDir);
DateTime endConstructionTime = DateTime.Now;
Console.WriteLine("Index Construction Time: {0}", endConstructionTime - startTime);
// generate some test queries
const int NUM_QUERIES = 10;
List <double[]> queries = new List <double[]>(NUM_QUERIES);
for (int i = 0; i < NUM_QUERIES; i++)
{
queries.Add(Util.RandomWalk(Globals.TimeSeriesLength));
}
// full sequential scan
Console.WriteLine("Performing full sequential scan.");
Console.WriteLine("--------------------------------");
List <IndexFileDist[]> nnInfo = si.KNearestNeighborSequentialScan(10, queries);
Console.WriteLine();
// query results
Console.WriteLine("Performing exact and approximate search.");
Console.WriteLine("----------------------------------------");
int counter = 0;
for (int i = 0; i < NUM_QUERIES; i++)
{
IndexFileDist exactResult;
si.ExactSearch(queries[i], out exactResult);
IndexFileDist approxResult = Index <RawDataFormat> .MinFileEucDist(queries[i],
si.ApproximateSearch(queries[i]).FileName);
Assert.IsTrue(exactResult == nnInfo[i][0]);
if (approxResult == exactResult)
{
counter++;
Console.WriteLine(approxResult);
}
}
Console.WriteLine("{0} approximate results == exact results.", counter);
Console.WriteLine();
}
