private static void RunSingleIteration(TimekeepingDictionary <StudentPair> tkDict)
{
// Generate a list of all students
List <int> allStudentIds = Enumerable.Range(1, checked (RowCount * ColumnCount)).ToList();
// Randomly place them throughout the classroom
int[,] studentPlacements = new int[RowCount, ColumnCount];
for (int i = 0; i < RowCount; i++)
{
for (int j = 0; j < ColumnCount; j++)
{
studentPlacements[i, j] = allStudentIds.ChooseAndRemoveRandom();
}
}
Debug.Assert(allStudentIds.Count == 0, "Should've placed all students.");
// Now calculate exposure levels
TimeSpan adjacentExposure = TimeSpan.FromTicks((long)(IterationTime.Ticks * AdjacentExposureFactor));
TimeSpan diagonalExposure = TimeSpan.FromTicks((long)(IterationTime.Ticks * DiagonalExposureFactor));
// Calculate exposure left-right
for (int i = 0; i < RowCount - 1; i++)
{
for (int j = 0; j < ColumnCount; j++)
{
tkDict.AddTime(new StudentPair(studentPlacements[i, j], studentPlacements[i + 1, j]), adjacentExposure);
}
}
// Calculate exposure up-down
for (int i = 0; i < RowCount; i++)
{
for (int j = 0; j < ColumnCount - 1; j++)
{
tkDict.AddTime(new StudentPair(studentPlacements[i, j], studentPlacements[i, j + 1]), adjacentExposure);
}
}
// Calculate exposure diagonally
for (int i = 0; i < RowCount - 1; i++)
{
for (int j = 0; j < ColumnCount - 1; j++)
{
tkDict.AddTime(new StudentPair(studentPlacements[i, j], studentPlacements[i + 1, j + 1]), diagonalExposure);
tkDict.AddTime(new StudentPair(studentPlacements[i + 1, j], studentPlacements[i, j + 1]), diagonalExposure);
}
}
}
/// <summary>
/// Runs the simulation, returning the number of students who were over-exposed
/// to a particular student (for simplicity, student id #1).
/// </summary>
public static int RunSimulationForOneStudent()
{
// Run the simulation (several iterations)
TimekeepingDictionary <StudentPair> tkDict = new TimekeepingDictionary <StudentPair>();
for (int i = 0; i < IterationCount; i++)
{
RunSingleIteration(tkDict);
}
// Find each pair who exceeded "risky" exposure level, and count the
// number of pairs which involve student #1.
return(tkDict
.Where(entry => entry.Value >= ExposureRiskThreshold)
.Where(entry => entry.Key.GetStudentIds().Contains(1))
.Select(entry => entry.Key)
.Distinct()
.Count());
}
/// <summary>
/// Runs the simulation, returning the number of students (not student pairs)
/// whose total exposure to any other single student exceeds the specified
/// CDC risk leel.
/// </summary>
public static int RunSimulationForAllStudents(out bool wasTrackedStudentOverexposed)
{
// Run the simulation (several iterations)
TimekeepingDictionary <StudentPair> tkDict = new TimekeepingDictionary <StudentPair>();
for (int i = 0; i < IterationCount; i++)
{
RunSingleIteration(tkDict);
}
// Now count the number of students who exceeded risky exposure level
HashSet <int> idsOfStudentsAtRisk = tkDict
.Where(entry => entry.Value >= ExposureRiskThreshold)
.SelectMany(entry => entry.Key.GetStudentIds())
.ToHashSet();
// Assuming we're tracking a single student (say, student id #1),
// out a value stating whether this particular student was overexposed
// to any other student.
wasTrackedStudentOverexposed = idsOfStudentsAtRisk.Contains(1);
return(idsOfStudentsAtRisk.Count);
}
