protected override async Task <double[]> EvaluateCellsBatchAsync(IRequestContext context, ComputationalContext computationalContext, IEnumerable <GeoCellTuple> cells)
{
await SaveObservationsAndDalanayDiagsForCells(context, computationalContext, cells);
VariogramModule.IVariogramFitter variogramFitter = new LMDotNetVariogramFitter.Fitter();
Dictionary <ITimeSegment, VariogramModule.IVariogram> variograms = new Dictionary <ITimeSegment, VariogramModule.IVariogram>();
Dictionary <ITimeSegment, IObservationsInformation> observations = (Dictionary <ITimeSegment, IObservationsInformation>)computationalContext["observations"];
LimitedConcurrencyLevelTaskScheduler lclts = new LimitedConcurrencyLevelTaskScheduler(Environment.ProcessorCount);
TaskFactory taskFactory = new TaskFactory(lclts);
var variogramTasks = observations.Select(pair => taskFactory.StartNew(() =>
{
ITimeSegment ts = pair.Key;
TraceVerbose(string.Format("Fitting variogram for {0} ({1} observations)", ts, pair.Value.Observations.Length));
Stopwatch sw1 = Stopwatch.StartNew();
var lats = pair.Value.Observations.Select(o => o.Latitude).ToArray();
var lons = pair.Value.Observations.Select(o => o.Longitude).ToArray();
var vals = pair.Value.Observations.Select(o => o.Value).ToArray();
var pointSet = new EmpVariogramBuilder.PointSet(lats, lons, vals);
var dist = FuncConvert.ToFSharpFunc(new Converter <Tuple <double, double>, FSharpFunc <Tuple <double, double>, double> >(t1 =>
FuncConvert.ToFSharpFunc(new Converter <Tuple <double, double>, double>(t2 => SphereMath.GetDistance(t1.Item1, t1.Item2, t2.Item1, t2.Item2)))));
var empVar = EmpVariogramBuilder.EmpiricalVariogramBuilder.BuildEmpiricalVariogram(pointSet, dist);
var fitted_variogram = variogramFitter.Fit(empVar);
VariogramModule.IVariogram effectiveVariogram = null;
sw1.Stop();
if (FSharpOption <VariogramModule.IDescribedVariogram> .get_IsSome(fitted_variogram))
{
effectiveVariogram = fitted_variogram.Value;
TraceVerbose(string.Format("Variogram fited for {0} ({1} observations) in {2}", ts, pair.Value.Observations.Length, sw1.Elapsed));
}
else
{
TraceWarning(string.Format("Variogram fitting failed for {0} ({1} observations) in {2}. Using fallback variogram", ts, pair.Value.Observations.Length, sw1.Elapsed));
effectiveVariogram = variogramFitter.GetFallback(empVar);
}
lock ("saving_variograms")
{
variograms.Add(ts, effectiveVariogram);
}
}));
TraceVerbose(string.Format("Starting calculations of linear weights for all cells"));
Stopwatch sw2 = Stopwatch.StartNew();
var weigths = CalcLinearWeights(computationalContext, cells);
sw2.Stop();
TraceVerbose(string.Format("calculations of linear weights for all cells ended in {0}", sw2.Elapsed));
TraceVerbose(string.Format("Waiting for all variograms to be computed"));
await Task.WhenAll(variogramTasks);
TraceVerbose(string.Format("All variograms are computed. Calculating variances and values"));
Stopwatch sw3 = Stopwatch.StartNew();
var resultValues = cells.Zip(weigths, (cell, weightTuple) =>
{
ITimeSegment ts = cell.Time;
var weight = weightTuple.Item2;
VariogramModule.IVariogram variogram = variograms[ts];
var observation = observations[ts].Observations;
Debug.Assert(Math.Abs(weight.Sum(w => w.Weight) - 1.0) < 1e-10);
double sill = variogram.Sill;
double cellLat = (cell.LatMax + cell.LatMin) * 0.5;
double cellLon = (cell.LonMax + cell.LonMin) * 0.5;
//var = cov(0)+ sum sum (w[i]*w[j]*cov(i,j))-2.0*sum(w[i]*cov(x,i))
double cov_at_0 = sill;
double acc = cov_at_0; //cov(0)
for (int i = 0; i < weight.Length; i++)
{
double w = weight[i].Weight;
int idx1 = weight[i].DataIndex;
double lat1 = observation[idx1].Latitude;
double lon1 = observation[idx1].Longitude;
for (int j = 0; j < i; j++)
{
int idx2 = weight[j].DataIndex;
double lat2 = observation[idx2].Latitude;
double lon2 = observation[idx2].Longitude;
double dist = SphereMath.GetDistance(lat1, lon1, lat2, lon2);
double cov = sill - variogram.GetGamma(dist);
acc += 2.0 * w * weight[j].Weight * cov;
}
acc += w * w * cov_at_0; //diagonal elements
double dist2 = SphereMath.GetDistance(lat1, lon1, cellLat, cellLon);
double cov2 = sill - variogram.GetGamma(dist2);
acc -= 2.0 * w * cov2;
}
return(Tuple.Create(cell, Math.Sqrt(acc), weight.Sum(w => observation[w.DataIndex].Value * w.Weight)));
}).ToArray();
sw3.Stop();
TraceVerbose(string.Format("All sigmas calulated in {0}", sw3.Elapsed));
computationalContext.Add("results", resultValues);
return(resultValues.Select(r => r.Item2).ToArray());
}
