public void TestReadmeExample0()
{
int binCount = 3;
Tally <float> tally = new Tally <float>(binCount, x => (int)(x * binCount));
// Some where, this is called repeatedly.
// tally.Add(neuron.value);
// But let's supply some fake values for demonstration purposes.
tally.Add(0.2f);
tally.Add(0.1f);
tally.Add(0.4f);
tally.Add(0.5f);
// Finally we analyze it.
float[] p = tally.probability;
Assert.Equal(new [] { 2 / 4f, 2 / 4f, 0f }, p);
float H = ProbabilityDistribution.Entropy(p);
// Here's the entropy without any normalization.
Assert.Equal(0.7f, H, 1);
// Let's use a base of 2 so the entropy is in the units of bits.
float Hbits = ProbabilityDistribution.Entropy(p, 2);
Assert.Equal(1f, Hbits, 1);
// So this neuron's value carries one bit of information. It's either going
// into the first bin or the second bin at an equal probability and never
// going into the third bin.
}
static Tally GetTally(List <CalcExpression> p, bool numbersOnly)
{
var tally = new Tally(numbersOnly);
foreach (CalcExpression e in p)
{
tally.Add(e);
}
return(tally);
}
public void TestReadmeExample1()
{
int binCount = 4;
Tally <float, float> tally
= new Tally <float, float>(binCount, x => (int)(x * binCount),
binCount, y => (int)(y * binCount));
// Some where, this is called repeatedly.
// tally.Add(sensor.value, effector.value);
// But let's supply some fake values for demonstration purposes.
tally.Add(0.6f, 0.1f);
tally.Add(0.5f, 0.5f);
tally.Add(0.7f, 0.9f);
tally.Add(0.7f, 0.3f);
// Finally we analyze it.
float[] px = tally.probabilityX;
Assert.Equal(new [] { 0f, 0f, 1f, 0f }, px);
float[] py = tally.probabilityY;
Assert.Equal(new [] { 1 / 4f, 1 / 4f, 1 / 4f, 1 / 4f }, py);
float[,] pxy = tally.probabilityXY;
Assert.Equal(new [, ] {
{ 0f, 0f, 0f, 0f },
{ 0f, 0f, 0f, 0f },
{ 1 / 4f, 1 / 4f, 1 / 4f, 1 / 4f },
{ 0f, 0f, 0f, 0f },
}, pxy);
float Hsensor = ProbabilityDistribution.Entropy(px, 2);
float Heffector = ProbabilityDistribution.Entropy(py, 2);
// H(effector | sensor)
float Heffector_sensor = ProbabilityDistribution.ConditionalEntropyYX(pxy, px, 2);
Assert.Equal(0f, Hsensor, 1);
// So the sensor carries no information. It's going to the second bin always
// based on what's been seen.
Assert.Equal(2f, Heffector, 1);
// The effector carries 2 bits of information. It could show up in any of
// the bins with equal probability. It would take two bits to describe which bin.
Assert.Equal(2f, Heffector_sensor, 1);
// Given that we know the sensor, there's no reduction in randomness for the
// effector. In fact since H(effector) = H(effector|sensor) we now know that
// the sensor and effector are entirely independent of one another.
}
private TraceItem StartTrace(TraceKind kind, PatternElement source)
{
TraceItem traceElement = new TraceItem
{
Kind = kind,
PatternElement = source,
State = TraceState.InProgress
};
Items.Add(traceElement);
if (!Tally.TryGetValue(source, out TallyEntry entry))
{
entry = new TallyEntry
{
LastPosition = 0,
Count = 0
};
Tally.Add(source, entry);
}
if (entry.LastPosition != State.Enumerator.Index)
{
entry.Count = 0;
entry.LastPosition = State.Enumerator.Index;
}
entry.Count++;
if (entry.Count > CycleThreshold)
{
throw new Exception("Possible cycle detected!");
}
return(traceElement);
}
private static object Sum(List<Expression> p)
{
var tally = new Tally();
foreach (var e in p)
{
tally.Add(e);
}
return tally.Sum();
}
