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 List <IndexFileDist[]> KNearestNeighborSequentialScan(int k, List <double[]> tsList)
{
CostCounter counter = new CostCounter(0, 0);
if (k > NumTimeSeries)
{
Console.WriteLine("K > number of time series, setting K to number of time series.");
k = NumTimeSeries;
}
List <IntervalHeap <IndexFileDist> > neighbors =
new List <IntervalHeap <IndexFileDist> >(tsList.Count);
for (int l = 0; l < tsList.Count; l++)
{
neighbors.Add(new IntervalHeap <IndexFileDist>(k + 1));
}
Console.Write("Retreiving All Index Files:");
string[] indexFiles = Directory.GetFiles(Globals.IndexRootDir,
"*.*.txt", SearchOption.AllDirectories);
Console.WriteLine(" {0} files.", indexFiles.Length);
int frac = indexFiles.Length / 10;
int srchFiles = 0;
int srchTs = 0;
int pos = 0;
int length = 0;
byte[] temp;
SaxData tmp;
double[] data;
int line;
double dist;
BinaryReader r;
foreach (string f in indexFiles)
{
// disp update
if (srchFiles % (frac == 0 ? 1 : frac) == 0)
{
Console.Write("\r{0}", srchFiles);
}
srchFiles++;
counter.IO++;
using (FileStream sr = new FileStream(f, FileMode.Open, FileAccess.Read))
{
r = new BinaryReader(sr);
pos = 0;
length = (int)r.BaseStream.Length; // get the file lenght
line = 0;
while (pos < length)
{
srchTs++;
temp = r.ReadBytes(SaxData.ByteLength(typeof(DATAFORMAT)));
tmp = SaxData.Parse <DATAFORMAT>(temp);
data = tmp.dl.GetTimeSeries();
for (int query = 0; query < tsList.Count; query++) // compute distance to each query
{
dist = Util.EuclideanDistance(data, tsList[query]);
neighbors[query].Add(new IndexFileDist(f, line + 1, dist));
if (neighbors[query].Count > k) //
{
neighbors[query].DeleteMax();
}
}
counter.distance += tsList.Count;
line++;
pos = pos + SaxData.ByteLength(typeof(DATAFORMAT));
}
r.Close();
sr.Close();
}
}
Console.WriteLine();
Console.WriteLine("{0} files {1} entries searched.", srchFiles, srchTs);
List <IndexFileDist[]> result = new List <IndexFileDist[]>(tsList.Count);
for (int l = 0; l < tsList.Count; l++)
{
result.Add(new IndexFileDist[k]);
}
for (int t = 0; t < tsList.Count; t++)
{
for (int i = 0; i < k; i++)
{
result[t][i] = neighbors[t].DeleteMin();
}
}
return(result);
}
public static void SearchQualityExperiment()
{
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);
// avg over queries
const int NUM_QUERIES = 100;
List <double[]> queries = new List <double[]>(NUM_QUERIES);
for (int i = 0; i < NUM_QUERIES; i++)
{
queries.Add(Util.RandomWalk(Globals.TimeSeriesLength));
}
// measured metrics
double approxSearchDist = 0;
double approxSearchNodeDist = 0;
double approxSearchNodeSize = 0;
CostCounter exactSearchCosts = new CostCounter();
for (int i = 0; i < queries.Count; ++i)
{
// exact search
IndexFileDist eRes;
exactSearchCosts += si.ExactSearch(queries[i], out eRes);
// approximate search
TermEntry approxNode = si.ApproximateSearch(queries[i]);
double mDist = double.MaxValue;
List <RawDataFormat> nodeEntries = si.ReturnDataFormatFromTermEntry(approxNode);
double sumDists = 0;
foreach (RawDataFormat rd in nodeEntries)
{
double dist = Util.EuclideanDistance(queries[i], rd.GetTimeSeries());
sumDists += dist;
if (dist < mDist)
{
mDist = dist;
}
}
approxSearchDist += mDist;
approxSearchNodeDist += sumDists / nodeEntries.Count;
approxSearchNodeSize += nodeEntries.Count;
}
approxSearchDist /= queries.Count;
approxSearchNodeDist /= queries.Count;
approxSearchNodeSize /= queries.Count;
using (StreamWriter sw = new StreamWriter(Path.Combine(ROOT_DIR, "searchQuality.txt")))
{
string baseFormat = string.Format("{0}:NumTs_{1}:Th_{2}:Wl_{3}:NewPolicy", NUM_TIMESERIES, Globals.IndexNumMaxEntries, Globals.TimeSeriesLength, Globals.NewSplitPolicy);
sw.WriteLine(baseFormat);
sw.WriteLine("ExactSearchNumIO {0}", exactSearchCosts.IO / (double)queries.Count);
sw.WriteLine("ExactSearchNumCalcuations {0}", exactSearchCosts.distance / (double)queries.Count);
sw.WriteLine("ApproxSearchDistance {0}", approxSearchDist);
sw.WriteLine("ApproxSearchAverageNodeDistance {0}", approxSearchNodeDist);
sw.WriteLine("ApproxSearchAverageNodeSize {0}", approxSearchNodeSize);
sw.WriteLine("ValidationString ");
foreach (double[] query in queries)
{
sw.Write("{0} ", query[1]);
}
sw.WriteLine();
}
}