public void EDRaHeavilyBiasedReservoirOf100OutOf1000Elements()
{
ExponentiallyDecayingReservoir reservoir = new ExponentiallyDecayingReservoir(1000, 0.01);
for (int i = 0; i < 100; i++)
{
reservoir.Update(i);
}
reservoir.Size.Should().Be(100);
var snapshot = reservoir.Snapshot;
snapshot.Size.Should().Be(100);
snapshot.Values.Should().OnlyContain(v => 0 <= v && v < 100);
}
public void EDRlongPeriodsOfInactivityShouldNotCorruptSamplingState()
{
TestClock clock = new TestClock();
TestScheduler scheduler = new TestScheduler(clock);
ExponentiallyDecayingReservoir reservoir = new ExponentiallyDecayingReservoir(10, 0.015, clock, scheduler);
// add 1000 values at a rate of 10 values/second
for (int i = 0; i < 1000; i++)
{
reservoir.Update(1000 + i);
clock.Advance(TimeUnit.Milliseconds, 100);
}
reservoir.Snapshot.Size.Should().Be(10);
reservoir.Snapshot.Values.Should().OnlyContain(v => 1000 <= v && v < 2000);
// wait for 15 hours and add another value.
// this should trigger a rescale. Note that the number of samples will be reduced to 2
// because of the very small scaling factor that will make all existing priorities equal to
// zero after rescale.
clock.Advance(TimeUnit.Hours, 15);
reservoir.Update(2000);
var snapshot = reservoir.Snapshot;
snapshot.Size.Should().Be(2);
snapshot.Values.Should().OnlyContain(v => 1000 <= v && v < 3000);
// add 1000 values at a rate of 10 values/second
for (int i = 0; i < 1000; i++)
{
reservoir.Update(3000 + i);
clock.Advance(TimeUnit.Milliseconds, 100);
}
var finalSnapshot = reservoir.Snapshot;
finalSnapshot.Size.Should().Be(10);
// TODO: double check the Skip first value - sometimes first value is 2000 - which might or not be correct
finalSnapshot.Values.Skip(1).Should().OnlyContain(v => 3000 <= v && v < 4000);
}