public static ILinkFunction Get(LinkFunctionType link)
{
ILinkFunction result = null;
switch (link)
{
case LinkFunctionType.Absolute: result = new AbsoluteLinkFunction(); break;
case LinkFunctionType.Cauchit: result = new CauchitLinkFunction(); break;
case LinkFunctionType.Identity: result = new IdentityLinkFunction(); break;
case LinkFunctionType.Inverse: result = new InverseLinkFunction(); break;
case LinkFunctionType.InverseSquared: result = new InverseSquaredLinkFunction(); break;
case LinkFunctionType.Logit: result = new LogitLinkFunction(); break;
case LinkFunctionType.Log: result = new LogLinkFunction(); break;
case LinkFunctionType.LogLog: result = new LogLogLinkFunction(); break;
case LinkFunctionType.Probit: result = new ProbitLinkFunction(); break;
case LinkFunctionType.Sin: result = new SinLinkFunction(); break;
case LinkFunctionType.Threshold: result = new ThresholdLinkFunction(); break;
}
return(result);
}
public void DerivativeTest()
{
double beta = 0.52;
double constant = 2.42;
double[] expected =
{
5.84785, 6.15998, 6.48877, 6.83512, 7.19995, 7.58425,
7.98906, 8.41549, 8.86467, 9.33783, 9.83624
};
LogLinkFunction target = new LogLinkFunction(beta, constant);
for (int i = 0; i < 11; i++)
{
double x = i / 10.0;
double y = target.Inverse(x);
double d1 = target.Derivative(x);
double d2 = target.Derivative2(y);
Assert.AreEqual(expected[i], d1, 1e-5);
Assert.AreEqual(expected[i], d2, 1e-5);
Assert.IsFalse(Double.IsNaN(d1));
Assert.IsFalse(Double.IsNaN(d2));
}
}
public void TestException()
{
var fn = new LogLinkFunction();
double[] x = { 1, 2 };
fn.Evaluate(x);
}
public void TestEvaluate()
{
var fn = new LogLinkFunction();
double[] x = { 2 };
double y = fn.Evaluate(x);
Assert.AreEqual(0.6931471805599453, y, AIFH.DefaultPrecision);
}
public void LogLinkFunctionConstructorTest2()
{
LogLinkFunction target = new LogLinkFunction();
Assert.AreEqual(1, target.B);
Assert.AreEqual(0, target.A);
for (int i = 0; i < 11; i++)
{
double x = i / 10.0;
double y = Math.Log(x);
Assert.AreEqual(y, target.Function(x), 1e-10);
Assert.AreEqual(x, target.Inverse(y), 1e-10);
}
}
public void LogLinkFunctionConstructorTest()
{
double beta = 0.52;
double constant = 2.42;
LogLinkFunction target = new LogLinkFunction(beta, constant);
Assert.AreEqual(beta, target.B);
Assert.AreEqual(constant, target.A);
for (int i = 0; i < 11; i++)
{
double x = i / 10.0;
double y = (Math.Log(x) - constant) / beta;
Assert.AreEqual(y, target.Function(x), 1e-10);
Assert.AreEqual(x, target.Inverse(y), 1e-10);
}
}
public void TestBasic()
{
var reg = new MultipleLinearRegression(1);
Assert.AreEqual(2, reg.LongTermMemory.Length);
var lnk = new LogLinkFunction();
reg.LinkFunction = lnk;
Assert.IsTrue(reg.LinkFunction == lnk);
reg.LongTermMemory[0] = 1;
reg.LongTermMemory[1] = 2;
double[] input = { 1.0 };
double[] output = reg.ComputeRegression(input);
Assert.AreEqual(1, output.Length);
Assert.AreEqual(1.0986122886681098, output[0], AIFH.DefaultPrecision);
}
