public void Predict()
{
EbisuModel m = new EbisuModel(2, 2, 2);
double p = Ebisu.PredictRecall(m, 2, true);
Assert.AreEqual(0.5, p, EPS, "1 + 1 should equal 2");
}
public void TestAgainstReference()
{
try
{
// All this boilerplate is just to load JSON
double maxTol = 5e-3;
string path = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), @"Ebisu/Ebisu_test.json");
string[] testData = File.ReadAllLines(path);
JArray expectedResult = (JArray)JsonConvert.DeserializeObject(testData[0]);
foreach (var child in expectedResult)
{
//subtest might be either
// a) ["update", [3.3, 4.4, 1.0], [0, 5, 0.1], {"post": [7.333641958415551, 8.949256654818793,
// 0.4148304099305316]}] or b) ["predict", [34.4, 34.4, 1.0], [5.5], {"mean": 0.026134289032202798}]
//
// In both cases, the first two elements are a string and an array of numbers. Then the remaining vary depend on
// what that string is. where the numbers are arbitrary. So here we go...
String operation = child[0].ToString();
JArray second = (JArray)child[1];
EbisuModel ebisu = new EbisuModel(double.Parse(second[2].ToString()), double.Parse(second[0].ToString()), double.Parse(second[1].ToString()));
if (operation.Equals("update"))
{
int successes = Convert.ToInt32(child[2][0].ToString());
int total = Convert.ToInt32(child[2][1].ToString());
double t = Convert.ToDouble(child[2][2].ToString());
JArray third = (JArray)child[3].Last.Last;//subtest.get(3).get("post");
EbisuModel expected = new EbisuModel(double.Parse(third[2].ToString()), double.Parse(third[0].ToString()), double.Parse(third[1].ToString()));
IEbisu actual = Ebisu.UpdateRecall(ebisu, successes, total, t);
Assert.AreEqual(expected.getAlpha(), actual.getAlpha(), maxTol);
Assert.AreEqual(expected.getBeta(), actual.getBeta(), maxTol);
Assert.AreEqual(expected.getTime(), actual.getTime(), maxTol);
}
else if (operation.Equals("predict"))
{
double t = Convert.ToDouble(child[2][0].ToString());
double expected = Convert.ToDouble(child[3].First.Last.ToString());
double actual = Ebisu.PredictRecall(ebisu, t, true);
Assert.AreEqual(expected, actual, maxTol);
}
else
{
throw new Exception("unknown operation");
}
}
}
catch (Exception ex)
{
ex.StackTrace.ToString();
Console.WriteLine("¡¡¡OOOPS SOMETHING BAD HAPPENED!!!");
Assert.IsTrue(false);
}
}
public void TestHalflife()
{
double hl = 20.0;
EbisuModel m = new EbisuModel(hl, 2, 2);
Assert.True(Math.Abs(Ebisu.ModelToPercentileDecay(m, .5, true) - hl) > 1e-2);
Assert.True(Relerr(Ebisu.ModelToPercentileDecay(m, .5, 1e-6), hl) < 1e-3);
//Assert.Throws<Exception>(() => Ebisu.ModelToPercentileDecay(m, 0.5, 1e-150));
}
/**
* Actual worker method that calculates the posterior memory model at the same
* time in the future as the prior, and rebalances as necessary.
*/
private static IEbisu UpdateRecall(IEbisu prior, int successes, int total, double tnow,
bool rebalance, double tback)
{
double alpha = prior.getAlpha();
double beta = prior.getBeta();
double t = prior.getTime();
double dt = tnow / t;
double et = tback / tnow;
double[] binomlns = Enumerable.Range(0, total - successes + 1).Select(i => LogBinom(total - successes, i)).ToArray();
double[] logs =
Enumerable.Range(0, 3)
.Select(m =>
{
List <Double> a =
Enumerable.Range(0, total - successes + 1)
.Select(i => binomlns[i] + LogBeta(beta, alpha + dt * (successes + i) + m * dt * et)).ToList();
//.boxed()
//.collect(Collectors.toList());
List <Double> b = Enumerable.Range(0, total - successes + 1)
.Select(i => Math.Pow(-1.0, i)).ToList();
//.boxed()
//.collect(Collectors.toList());
return(LogSumExp(a, b)[0]);
}).ToArray();
double logDenominator = logs[0];
double logMeanNum = logs[1];
double logM2Num = logs[2];
double mean = Math.Exp(logMeanNum - logDenominator);
double m2 = Math.Exp(logM2Num - logDenominator);
double meanSq = Math.Exp(2 * (logMeanNum - logDenominator));
double sig2 = m2 - meanSq;
if (mean <= 0)
{
throw new Exception("invalid mean found");
}
if (m2 <= 0)
{
throw new Exception("invalid second moment found");
}
if (sig2 <= 0)
{
throw new Exception("invalid variance found " +
String.Format("a=%g, b=%g, t=%g, k=%d, n=%d, tnow=%g, mean=%g, m2=%g, sig2=%g", alpha,
beta, t, successes, total, tnow, mean, m2, sig2));
}
List <Double> newAlphaBeta = MeanVarToBeta(mean, sig2);
EbisuModel proposed = new EbisuModel(tback, newAlphaBeta[0], newAlphaBeta[1]);
return(rebalance ? Rebalance(prior, successes, total, tnow, proposed) : proposed);
}
public void Update()
{
IEbisu m = new EbisuModel(2, 2, 2);
IEbisu success = Ebisu.UpdateRecall(m, 1, 1, 2.0);
IEbisu failure = Ebisu.UpdateRecall(m, 0, 1, 2.0);
Assert.AreEqual(3.0, success.getAlpha(), 500 * EPS, "success/alpha");
Assert.AreEqual(2.0, success.getBeta(), 500 * EPS, "success/beta");
Assert.AreEqual(2.0, failure.getAlpha(), 500 * EPS, "failure/alpha");
Assert.AreEqual(3.0, failure.getBeta(), 500 * EPS, "failure/beta");
}
