private static void and()
{
// Create a simple binary AND
// classification problem:
double[][] problem =
{
// a b a + b
new double[] { 0, 0, 0 },
new double[] { 0, 1, 0 },
new double[] { 1, 0, 0 },
new double[] { 1, 1, 1 },
};
// Get the two first columns as the problem
// inputs and the last column as the output
// input columns
double[][] inputs = problem.GetColumns(0, 1);
// output column
int[] outputs = problem.GetColumn(2).ToInt32();
// Plot the problem on screen
ScatterplotBox.Show("AND", inputs, outputs).Hold();
// However, SVMs expect the output value to be
// either -1 or +1. As such, we have to convert
// it so the vector contains { -1, -1, -1, +1 }:
//
outputs = outputs.Apply(x => x == 0 ? -1 : 1);
// Create a new linear-SVM for two inputs (a and b)
SupportVectorMachine svm = new SupportVectorMachine(inputs: 2);
// Create a L2-regularized L2-loss support vector classification
var teacher = new LinearDualCoordinateDescent(svm, inputs, outputs)
{
Loss = Loss.L2,
Complexity = 1000,
Tolerance = 1e-5
};
// Learn the machine
double error = teacher.Run(computeError: true);
// Compute the machine's answers for the learned inputs
int[] answers = inputs.Apply(x => Math.Sign(svm.Compute(x)));
// Plot the results
ScatterplotBox.Show("SVM's answer", inputs, answers).Hold();
}
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 LinearDualCoordinateDescent(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;
double[][] inputs = dataset.Submatrix(null, 0, 1).ToJagged();
int[] 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 LinearDualCoordinateDescent(machine, projection, labels);
smo.UseComplexityHeuristic = true;
smo.Tolerance = 0.01;
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);
}
{
Accord.Math.Random.Generator.Seed = 0;
var projection = inputs.Apply(kernel.Transform);
var machine = new SupportVectorMachine(projection[0].Length);
var smo = new LinearDualCoordinateDescent(machine, projection, labels);
smo.UseComplexityHeuristic = true;
smo.Loss = Loss.L1;
double error = smo.Run();
Assert.AreEqual(0.2, 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(kernel.Transform(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);
}
}
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 LinearDualCoordinateDescent(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 LinearDualCoordinateDescent(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));
}
private static void xor()
{
// Create a simple binary XOR
// classification problem:
double[][] problem =
{
// a b a XOR b
new double[] { 0, 0, 0 },
new double[] { 0, 1, 1 },
new double[] { 1, 0, 1 },
new double[] { 1, 1, 0 },
};
// Get the two first columns as the problem
// inputs and the last column as the output
// input columns
double[][] inputs = problem.GetColumns(0, 1);
// output column
int[] outputs = problem.GetColumn(2).ToInt32();
// Plot the problem on screen
ScatterplotBox.Show("XOR", inputs, outputs).Hold();
// However, SVMs expect the output value to be
// either -1 or +1. As such, we have to convert
// it so the vector contains { -1, -1, -1, +1 }:
//
outputs = outputs.Apply(x => x == 0 ? -1 : 1);
// Create a new linear-SVM for two inputs (a and b)
SupportVectorMachine svm = new SupportVectorMachine(inputs: 2);
// Create a L2-regularized L2-loss support vector classification
var teacher = new LinearDualCoordinateDescent(svm, inputs, outputs)
{
Loss = Loss.L2,
Complexity = 1000,
Tolerance = 1e-5
};
// Learn the machine
double error = teacher.Run(computeError: true);
// Compute the machine's answers for the learned inputs
int[] answers = inputs.Apply(x => Math.Sign(svm.Compute(x)));
// Plot the results
ScatterplotBox.Show("SVM's answer", inputs, answers).Hold();
// Use an explicit kernel expansion to transform the
// non-linear classification problem into a linear one
//
// Create a quadratic kernel
Quadratic quadratic = new Quadratic(constant: 1);
// Project the inptus into a higher dimensionality space
double[][] expansion = inputs.Apply(quadratic.Transform);
// Create a new linear-SVM for the transformed input space
svm = new SupportVectorMachine(inputs: expansion[0].Length);
// Create the same learning algorithm in the expanded input space
teacher = new LinearDualCoordinateDescent(svm, expansion, outputs)
{
Loss = Loss.L2,
Complexity = 1000,
Tolerance = 1e-5
};
// Learn the machine
error = teacher.Run(computeError: true);
// Compute the machine's answers for the learned inputs
answers = expansion.Apply(x => Math.Sign(svm.Compute(x)));
// Plot the results
ScatterplotBox.Show("SVM's answer", inputs, answers).Hold();
}
private static void cancer()
{
// Create a new LibSVM sparse format data reader
// to read the Wisconsin's Breast Cancer dataset
//
var reader = new SparseReader("examples-sparse.txt");
int[] outputs; // Read the classification problem into dense memory
double[][] inputs = reader.ReadToEnd(sparse: false, labels: out outputs);
// The dataset has output labels as 4 and 2. We have to convert them
// into negative and positive labels so they can be properly processed.
//
outputs = outputs.Apply(x => x == 2 ? -1 : +1);
// Create a new linear-SVM for the problem dimensions
var svm = new SupportVectorMachine(inputs: reader.Dimensions);
// Create a learning algorithm for the problem's dimensions
var teacher = new LinearDualCoordinateDescent(svm, inputs, outputs)
{
Loss = Loss.L2,
Complexity = 1000,
Tolerance = 1e-5
};
// Learn the classification
double error = teacher.Run();
// Compute the machine's answers for the learned inputs
int[] answers = inputs.Apply(x => Math.Sign(svm.Compute(x)));
// Create a confusion matrix to show the machine's performance
var m = new ConfusionMatrix(predicted: answers, expected: outputs);
// Show it onscreen
DataGridBox.Show(new ConfusionMatrixView(m));
}
