private double[] gradient(double[] w)
{
double[] y = Outputs;
double p = Epsilon;
sizeI = 0;
for (int i = 0; i < y.Length; i++)
{
double d = z[i] - y[i];
// generate index set I
if (d < -p)
{
z[sizeI] = C[i] * (d + p);
I[sizeI] = i;
sizeI++;
}
else if (d > p)
{
z[sizeI] = C[i] * (d - p);
I[sizeI] = i;
sizeI++;
}
}
LinearNewtonMethod.subXTv(Kernel, Inputs, biasIndex, I, sizeI, z, g);
for (int i = 0; i < w.Length; i++)
{
g[i] = w[i] + 2 * g[i];
}
return(g);
}
private double objective(double[] w)
{
double[] y = Outputs;
double p = Epsilon;
LinearNewtonMethod.Xv(Kernel, Inputs, biasIndex, w, z);
double f = 0;
for (int i = 0; i < w.Length; i++)
{
f += w[i] * w[i];
}
f /= 2;
for (int i = 0; i < y.Length; i++)
{
double d = z[i] - y[i];
if (d < -p)
{
f += C[i] * (d + p) * (d + p);
}
else if (d > p)
{
f += C[i] * (d - p) * (d - p);
}
}
return(f);
}
private double[] hessian(double[] s)
{
LinearNewtonMethod.subXv(Kernel, Inputs, biasIndex, I, sizeI, s, wa);
for (int i = 0; i < sizeI; i++)
{
wa[i] = C[I[i]] * wa[i];
}
LinearNewtonMethod.subXTv(Kernel, Inputs, biasIndex, I, sizeI, wa, h);
for (int i = 0; i < s.Length; i++)
{
h[i] = s[i] + 2 * h[i];
}
return(h);
}
public void LearnTest()
{
double[][] inputs =
{
new double[] { -1, -1 },
new double[] { -1, 1 },
new double[] { 1, -1 },
new double[] { 1, 1 }
};
int[] xor =
{
-1,
1,
1,
-1
};
var kernel = new Polynomial(2, 0.0);
double[][] augmented = new double[inputs.Length][];
for (int i = 0; i < inputs.Length; i++)
augmented[i] = kernel.Transform(inputs[i]);
SupportVectorMachine machine = new SupportVectorMachine(augmented[0].Length);
// Create the Least Squares Support Vector Machine teacher
var learn = new LinearNewtonMethod(machine, augmented, xor);
// Run the learning algorithm
double error = learn.Run();
Assert.AreEqual(0, error);
int[] output = augmented.Apply(p => Math.Sign(machine.Compute(p)));
for (int i = 0; i < output.Length; i++)
Assert.AreEqual(System.Math.Sign(xor[i]), System.Math.Sign(output[i]));
}
public void ComputeTest5()
{
var dataset = SequentialMinimalOptimizationTest.yinyang;
var inputs = dataset.Submatrix(null, 0, 1).ToArray();
var labels = dataset.GetColumn(2).ToInt32();
var kernel = new Polynomial(2, 0);
{
var machine = new KernelSupportVectorMachine(kernel, inputs[0].Length);
var smo = new SequentialMinimalOptimization(machine, inputs, labels);
smo.UseComplexityHeuristic = true;
double error = smo.Run();
Assert.AreEqual(0.2, error);
Assert.AreEqual(0.11714451552090824, smo.Complexity);
int[] actual = new int[labels.Length];
for (int i = 0; i < actual.Length; i++)
actual[i] = Math.Sign(machine.Compute(inputs[i]));
ConfusionMatrix matrix = new ConfusionMatrix(actual, labels);
Assert.AreEqual(20, matrix.FalseNegatives);
Assert.AreEqual(0, matrix.FalsePositives);
Assert.AreEqual(30, matrix.TruePositives);
Assert.AreEqual(50, matrix.TrueNegatives);
}
{
Accord.Math.Tools.SetupGenerator(0);
var projection = inputs.Apply(kernel.Transform);
var machine = new SupportVectorMachine(projection[0].Length);
var smo = new LinearNewtonMethod(machine, projection, labels);
smo.UseComplexityHeuristic = true;
double error = smo.Run();
Assert.AreEqual(0.18, error);
Assert.AreEqual(0.11714451552090821, smo.Complexity, 1e-15);
int[] actual = new int[labels.Length];
for (int i = 0; i < actual.Length; i++)
actual[i] = Math.Sign(machine.Compute(projection[i]));
ConfusionMatrix matrix = new ConfusionMatrix(actual, labels);
Assert.AreEqual(17, matrix.FalseNegatives);
Assert.AreEqual(1, matrix.FalsePositives);
Assert.AreEqual(33, matrix.TruePositives);
Assert.AreEqual(49, matrix.TrueNegatives);
}
}
public static void train_one(Problem prob, Parameters param, out double[] w, double Cp, double Cn)
{
double[][] inputs = prob.Inputs;
int[] labels = prob.Outputs.Apply(x => x >= 0 ? 1 : -1);
double eps = param.Tolerance;
int pos = 0;
for (int i = 0; i < labels.Length; i++)
if (labels[i] >= 0) pos++;
int neg = prob.Outputs.Length - pos;
double primal_solver_tol = eps * Math.Max(Math.Min(pos, neg), 1.0) / prob.Inputs.Length;
SupportVectorMachine svm = new SupportVectorMachine(prob.Dimensions);
ISupportVectorMachineLearning teacher = null;
switch (param.Solver)
{
case LibSvmSolverType.L2RegularizedLogisticRegression:
// l2r_lr_fun
teacher = new ProbabilisticNewtonMethod(svm, inputs, labels)
{
PositiveWeight = Cp,
NegativeWeight = Cn,
Tolerance = primal_solver_tol
}; break;
case LibSvmSolverType.L2RegularizedL2LossSvc:
// fun_obj=new l2r_l2_svc_fun(prob, C);
teacher = new LinearNewtonMethod(svm, inputs, labels)
{
PositiveWeight = Cp,
NegativeWeight = Cn,
Tolerance = primal_solver_tol
}; break;
case LibSvmSolverType.L2RegularizedL2LossSvcDual:
// solve_l2r_l1l2_svc(prob, w, eps, Cp, Cn, L2R_L2LOSS_SVC_DUAL);
teacher = new LinearCoordinateDescent(svm, inputs, labels)
{
Loss = Loss.L2,
PositiveWeight = Cp,
NegativeWeight = Cn,
}; break;
case LibSvmSolverType.L2RegularizedL1LossSvcDual:
// solve_l2r_l1l2_svc(prob, w, eps, Cp, Cn, L2R_L1LOSS_SVC_DUAL);
teacher = new LinearCoordinateDescent(svm, inputs, labels)
{
Loss = Loss.L1,
PositiveWeight = Cp,
NegativeWeight = Cn,
}; break;
case LibSvmSolverType.L1RegularizedLogisticRegression:
// solve_l1r_lr(&prob_col, w, primal_solver_tol, Cp, Cn);
teacher = new ProbabilisticCoordinateDescent(svm, inputs, labels)
{
PositiveWeight = Cp,
NegativeWeight = Cn,
Tolerance = primal_solver_tol
}; break;
case LibSvmSolverType.L2RegularizedLogisticRegressionDual:
// solve_l2r_lr_dual(prob, w, eps, Cp, Cn);
teacher = new ProbabilisticDualCoordinateDescent(svm, inputs, labels)
{
PositiveWeight = Cp,
NegativeWeight = Cn,
Tolerance = primal_solver_tol,
}; break;
}
Trace.WriteLine("Training " + param.Solver);
// run the learning algorithm
var sw = Stopwatch.StartNew();
double error = teacher.Run();
sw.Stop();
// save the solution
w = svm.ToWeights();
Trace.WriteLine(String.Format("Finished {0}: {1} in {2}",
param.Solver, error, sw.Elapsed));
}
