public async Task ComputeCompanyStatistics()
{
numOfDrivers = await _driverRepository.CountAsync();
IEnumerable <Leg> legs = await _legRepository.ListAsync();
pickups = legs.Select(leg => leg.NumOfPassengersPickedUp).Sum();
milesDriven = legs.Select(leg => leg.Distance).Sum();
if (await _legRepository.CountAsync() > 0)
{
averagePickupDelay = legs.Select(leg =>
leg.StartTime.Subtract(leg.PickupRequestTime.GetValueOrDefault(leg.StartTime)).TotalMinutes).Average();
}
totalFares = legs.Select(leg => leg.Fare * leg.NumOfPassengersAboard).Sum();
totalCosts = legs.Select(leg => leg.GetTotalFuelCost()).Sum();
netProfit = totalFares - totalCosts;
}
public async Task <IEnumerable <Leg> > Get()
{
return(await _legRepository.ListAsync());
}
/// <summary>
/// Train on number of clusters using gap statistic
/// </summary>
private async Task ComputeK(int maxK = 100, int B = 10, int driverID = 0, DateTime?startDate = null, DateTime?endDate = null)
{
double[] Wk = new double[maxK];
double[][] Wref_kb = new double[maxK][];
double[] Gap = new double[maxK];
double[] sd = new double[maxK];
KMeansClusterCollection[] clusterCollections = new KMeansClusterCollection[maxK];
// obtain dataset
IEnumerable <Leg> legs = driverID == 0 ? await _legRepository.ListAsync()
: await _legRepository.ListForDriverAsync(driverID);
if (startDate == null)
{
startDate = DateTime.MinValue;
}
if (endDate == null)
{
endDate = DateTime.MaxValue;
}
legs = legs.Where(leg => leg.StartTime.CompareTo(startDate) >= 0 && leg.StartTime.CompareTo(endDate) < 0);
double[][] dataset = GetDataset(legs);
// first cluster the dataset varying K
for (int k = 1; k <= maxK; k++)
{
KMeans kMeans = new KMeans(k)
{
// distance function for geographic coordinates
Distance = new GeographicDistance()
};
clusterCollections[k - 1] = kMeans.Learn(dataset);
double[][][] clusterData = ClusterPoints(dataset, k, clusterCollections[k - 1]);
// sum of pairwise distances
Wk[k - 1] = ComputeWk(clusterData, clusterCollections[k - 1]);
}
// then generate the reference data sets
double[] lowerBounds = new double[4];
double[] boxDimensions = new double[4];
for (int i = 0; i < 4; i++)
{
lowerBounds[i] = dataset.Select(l => l[i]).Min();
boxDimensions[i] = dataset.Select(l => l[i]).Max() - lowerBounds[i];
}
CorrectLongitudeBounds(lowerBounds, boxDimensions, 1);
CorrectLongitudeBounds(lowerBounds, boxDimensions, 3);
Random random = new Random();
for (int k = 1; k <= maxK; k++)
{
Wref_kb[k - 1] = new double[B];
for (int c = 0; c < B; c++)
{
double[][] refDataset = new double[dataset.Length][];
for (int i = 0; i < refDataset.Length; i++)
{
double[] dataPoint = new double[4];
for (int j = 0; j < 4; j++)
{
dataPoint[j] = random.NextDouble() * boxDimensions[j] + lowerBounds[j];
if ((j == 1 || j == 3) && dataPoint[j] > 180)
{
dataPoint[j] -= 360;
}
}
refDataset[i] = dataPoint;
}
// cluster reference dataset
KMeans refKmeans = new KMeans(k);
refKmeans.Distance = new GeographicDistance();
KMeansClusterCollection refClusters = refKmeans.Learn(refDataset);
// points in each cluster
double[][][] refClusterData = ClusterPoints(refDataset, k, refClusters);
// compute pairwise distance sum for refDataset
Wref_kb[k - 1][c] = ComputeWk(refClusterData, refClusters);
}
// compute gap statistic
double l_avg = Wref_kb[k - 1].Select(x => Log(x)).Average();
Gap[k - 1] = l_avg - Log(Wk[k - 1]);
sd[k - 1] = Sqrt(Wref_kb[k - 1].Select(x => (Log(x) - l_avg) * (Log(x) - l_avg)).Average());
// decide optimal k
if (k > 1 && Gap[k - 2] >= Gap[k - 1] - sd[k - 1])
{
ClusterCollection = clusterCollections[k - 2];
NumberOfClustersLastChanged = DateTime.Now;
return;
}
}
}
public async Task LearnFromDates(DateTime from, DateTime to)
{
int maxPickups = await GetMaxNumberOfPickups();
// train clustering algorithm
await _locationClustering.RetrainAsync(from, to);
// initialize storage arrays
int pickupElementSize = await GetMaxNumberOfPickups() + 1;
InitStorageArray(ref clusterFareClassRegressions, pickupElementSize - 1, NumberOfFareClassIntervals - 1);
InitStorageArray(ref clusterFareClassInputDensityKernels, pickupElementSize - 1, NumberOfFareClassIntervals);
InitStorageArray(ref clusterFareClassDistributionsUnivariate, pickupElementSize - 1, NumberOfFareClassIntervals);
InitStorageArray(ref clusterPickupFrequencies, pickupElementSize);
InitStorageArray(ref clusterPickupInputDensityKernels, pickupElementSize);
InitStorageArray(ref clusterPickupInputDensityKernelsUnivariate, pickupElementSize);
// for each cluster
for (int i = 0; i < _locationClustering.NumberOfClusters; i++)
{
// obtain data set
IEnumerable <Task <Pair <Leg, bool> > > decisionTasks = (await _legRepository.ListAsync())
.Where(leg => leg.StartTime.CompareTo(from) > 0 && leg.StartTime.CompareTo(to) < 0)
.Select(async(leg) =>
{
LegCoordinates coords = await _geocodingDbSync.GetLegCoordinatesAsync(leg.LegID);
double[] dp = (new decimal[] { coords.StartLatitude, coords.StartLongitude, coords.DestLatitude, coords.DestLongitude })
.Select(Convert.ToDouble).ToArray();
return(new Pair <Leg, bool>(leg, _locationClustering.ClusterCollection.Decide(dp) == i));
});
Pair <Leg, bool>[] decisions = await Task.WhenAll(decisionTasks);
// Data input values (pickup delay, travel time) in this cluster
IEnumerable <Leg> dataLegs = decisions.Where(pair => pair.Second).Select(pair => pair.First);
double[][] dataset = dataLegs
.Select(leg => new double[]
{
leg.PickupRequestTime.HasValue
? leg.StartTime.Subtract(leg.PickupRequestTime.Value).TotalMinutes
: 0,
leg.ArrivalTime.Subtract(leg.StartTime).TotalMinutes
}).ToArray();
// Fare classes in this cluster
int[] fareClasses = dataLegs
.Select(leg =>
{
for (int j = 0; j < FareClassIntervals.Count(); j++)
{
if (j < FareClassIntervals.Count() &&
Convert.ToDecimal(FareClassIntervals.ElementAt(j)) > leg.Fare)
{
return(j);
}
}
return(FareClassIntervals.Count());
}).ToArray();
// Pickup numbers in this cluster
int[] pickupNumbers = dataLegs.Select(leg => leg.NumOfPassengersPickedUp).ToArray();
// for each possible number of pickups
for (int n = 1; n <= maxPickups; n++)
{
double[][] dataSubset = dataset.Where((dp, k) => pickupNumbers[k] == n).ToArray();
int[] fareClassesSubset = fareClasses.Where((fc, k) => pickupNumbers[k] == n).ToArray();
if (dataSubset.Length == 0)
{
throw new ApplicationException("Insufficient data to make a reliable prediction");
}
// for each fare class interval boundary
for (int j = 0; j < NumberOfFareClassIntervals; j++)
{
// train logistic regression
if (j > 0 && clusterFareClassRegressions[i][n - 1][j - 1] == null)
{
clusterFareClassRegressions[i][n - 1][j - 1] = _logisticRegressionAnalysis
.Learn(dataSubset, fareClassesSubset.Select(fc => fc >= j ? 1.0 : 0.0).ToArray());
}
// train empirical density functions
if (fareClassesSubset.Count(fc => fc >= j) > 0.0)
{
double[][] dataSubsetSamples = dataSubset.Where((dp, k)
=> fareClassesSubset[k] >= j).ToArray();
MultivariateEmpiricalDistribution fareClassInputDistribution
= new MultivariateEmpiricalDistribution(dataSubsetSamples);
SetInputDistribution(fareClassInputDistribution, dataSubsetSamples,
out clusterFareClassInputDensityKernels[i][n - 1][j],
out clusterFareClassDistributionsUnivariate[i][n - 1][j]);
}
}
}
// compute pickup frequencies
for (int l = 0; l < pickupElementSize; l++)
{
clusterPickupFrequencies[i][l] = Convert.ToDouble(dataLegs.Count(leg => leg.NumOfPassengersPickedUp == l))
/ to.Subtract(from).TotalMinutes;
if (pickupNumbers.Any(pn => pn == l))
{
double[][] samples = dataset.Where((dp, k) => pickupNumbers[k] == l).ToArray();
MultivariateEmpiricalDistribution pickupInputDistribution
= new MultivariateEmpiricalDistribution(samples);
SetInputDistribution(pickupInputDistribution, samples,
out clusterPickupInputDensityKernels[i][l],
out clusterPickupInputDensityKernelsUnivariate[i][l]);
}
}
}
}
