/// <summary>Serves as unit test for <see cref="PraxisOptimizer"/> with respect to a quadratic test function with several constraints.
/// </summary>
public void FindMinimum_QuadraticTestFunction2WithConstraints_AnalyticResult()
{
/* Constraints:
* x_0 + x_1 + x_2 >= 6,
* -x_0 - x_1 + 2* x_2 >= 2,
* x_0, x_1, x_2 >= 0,
* */
var optimizer = new PraxisOptimizer(CreateStubRandomNumberStream(), PraxisOptimizerAbortCondition.Create(requiredNumberOfAcceptedPoints: 100), MultiDimOptimizerConstraintProvider.QuadraticPenalty);
var boxConstraint = optimizer.Constraint.Create(MultiDimRegion.Interval.Create(3, new[] { 0.0, 0.0, 0.0 }, new[] { Double.NaN, Double.NaN, Double.NaN }));
var inequalityConstraint = optimizer.Constraint.Create(new MultiDimRegion.LinearInequality(new DenseMatrix(3, 2, new[] { 1.0, 1.0, 1.0, -1.0, -1.0, 2.0 }), new[] { 6.0, 2.0 }));
var algorithm = optimizer.Create(boxConstraint, inequalityConstraint);
var A = new DenseMatrix(3, 3, new[] { 2.0, 1.0, 0.0, 1.0, 4.0, 2.0, 0.0, 2.0, 4.0 });
var b = new[] { 4.0, 6.0, 12.0 };
algorithm.Function = optimizer.Function.Create(3, x => 0.5 * DenseMatrix.GetBilinearForm(A, x) + BLAS.Level1.ddot(3, x, b));
var actualArgMin = new[] { 3.3333, 0.0001, 2.66 };
double actualMinimum;
var state = algorithm.FindMinimum(actualArgMin, out actualMinimum);
var expectedArgMin = new[] { 3 + 1.0 / 3.0, 0.0, 2 + 2.0 / 3.0 };
var expectedMinimum = 70.666666666666666;
Assert.That(actualMinimum, Is.EqualTo(expectedMinimum).Within(1E-7), String.Format("State: {0}; actual Minimum: {1}; expected Minimum: {2}; actual argMin: [{3}; {4}]; expected argMin: [{5}; {6}].", state, actualMinimum, expectedMinimum, actualArgMin[0], actualArgMin[1], expectedArgMin[0], expectedArgMin[1]));
Assert.That(actualArgMin, Is.EqualTo(expectedArgMin).AsCollection.Within(1E-7), String.Format("State: {0}; actual Minimum: {1}; expected Minimum: {2}; actual argMin: [{3}; {4}]; expected argMin: [{5}; {6}].", state, actualMinimum, expectedMinimum, actualArgMin[0], actualArgMin[1], expectedArgMin[0], expectedArgMin[1]));
}
public void FindMinimumGoldsteinPriceFunction_AnalyticResult(MultiDimOptimizerConstraintProvider constraintTransformation)
{
var randomNumberStream = CreateStubRandomNumberStream();
var optimizer = new PraxisOptimizer(randomNumberStream, PraxisOptimizer.StandardAbortCondition, constraintTransformation);
var constraint = optimizer.Constraint.Create(MultiDimRegion.Interval.Create(2, new[] { -2.0, -2.0 }, new[] { 2.0, 2.0 }));
var optimizerAlgorithm = optimizer.Create(constraint);
optimizerAlgorithm.Function = optimizer.Function.Create(2, z =>
{
var x = z[0];
var y = z[1];
return((1.0 + Math.Pow(x + y + 1.0, 2) * (19.0 - 14.0 * x + 3 * x * x - 14.0 * y + 6.0 * x * y + 3.0 * y * y)) * (30.0 + Math.Pow(2.0 * x - 3.0 * y, 2) * (18.0 - 32.0 * x + 12.0 * x * x + 48.0 * y - 36 * x * y + 27 * y * y)));
});
/* take an initial guess which is not extremly fare away from the argMin: */
var actualArgMin = new double[2];
actualArgMin[0] = 0.35;
actualArgMin[1] = -0.45; // Box-Constraint Transformation: sometimes one gets quite high arguments -/+ 3.13E19 arguments which yields to f(x) =\infinity and the algorithm fails
double actualMinimum;
var state = optimizerAlgorithm.FindMinimum(actualArgMin, out actualMinimum);
var expectedMinimum = 3.0;
Assert.That(actualMinimum, Is.EqualTo(expectedMinimum).Within(1E-2), "Minimum");
var expectedArgMin = new[] { 0.0, -1.0 };
Assert.That(actualArgMin, Is.EqualTo(expectedArgMin).AsCollection.Within(1E-1));
}
public void FindMinimum_QuadraticTestFunctionWithConstraints_AnalyticResult()
{
var optimizer = new PraxisOptimizer(CreateStubRandomNumberStream(), PraxisOptimizer.StandardAbortCondition, MultiDimOptimizerConstraintProvider.QuadraticPenalty);
/* Constraints:
* x_0 + x_1 = 3,
* x_0 >= 0,
* x_1 >= 0,
* x_0 + x_2 >= 2 */
var boxConstraint = optimizer.Constraint.Create(MultiDimRegion.Interval.Create(2, new[] { 0.0, 0.0 }, new[] { Double.NaN, Double.NaN }));
var equalityConstraint = optimizer.Constraint.Create(new MultiDimRegion.LinearEquality(new DenseMatrix(2, 1, new[] { 1.0, 1.0 }), new[] { 3.0 }));
var inequalityConstraint = optimizer.Constraint.Create(new MultiDimRegion.LinearInequality(new DenseMatrix(2, 1, new[] { 1.0, 1.0 }), new[] { 2.0 }));
var algorithm = optimizer.Create(boxConstraint, equalityConstraint, inequalityConstraint);
var A = new DenseMatrix(2, 2, new[] { 4.0, -2.0, -2.0, 4 - 0 }); // = (4 & -2 \\ -2 & 4)
var b = new[] { 6.0, 0.0 };
algorithm.Function = optimizer.Function.Create(2, x => 0.5 * DenseMatrix.GetBilinearForm(A, x) + BLAS.Level1.ddot(2, x, b));
var actualArgMin = new[] { 1.5, 1.5 }; // is a feasible point
double actualMinimum;
var state = algorithm.FindMinimum(actualArgMin, out actualMinimum);
var expectedArgMin = new[] { 1.0, 2.0 };
var expectedMinimum = 12.0;
Assert.That(actualMinimum, Is.EqualTo(expectedMinimum).Within(1E-7), String.Format("State: {0}; actual Minimum: {1}; expected Minimum: {2}; actual argMin: [{3}; {4}]; expected argMin: [{5}; {6}].", state, actualMinimum, expectedMinimum, actualArgMin[0], actualArgMin[1], expectedArgMin[0], expectedArgMin[1]));
Assert.That(actualArgMin, Is.EqualTo(expectedArgMin).AsCollection.Within(1E-7), String.Format("State: {0}; actual Minimum: {1}; expected Minimum: {2}; actual argMin: [{3}; {4}]; expected argMin: [{5}; {6}].", state, actualMinimum, expectedMinimum, actualArgMin[0], actualArgMin[1], expectedArgMin[0], expectedArgMin[1]));
}
public void FindMinimum_RosenbrockTestFunction_AnalyticResult(
[Values(2, 4, 5, 7)]
int d)
{
var randomNumberStream = CreateStubRandomNumberStream();
var optimizer = new PraxisOptimizer(randomNumberStream);
var optimizerAlgorithm = optimizer.Create(d);
optimizerAlgorithm.Function = optimizer.Function.Create(d, x =>
{
double y = 0.0;
for (int k = 0; k < d - 1; k++)
{
y += 100 * Math.Pow(x[k + 1] - x[k] * x[k], 2) + Math.Pow(x[k] - 1.0, 2);
}
return(y);
});
/* take an initial guess which is not extremly fare away from the argMin: */
var actualArgMin = new double[d];
for (int k = 0; k < d; k++)
{
actualArgMin[k] = Math.Min(k, 2.75) * Math.Pow(-1, k);
}
double actualMinimum;
var state = optimizerAlgorithm.FindMinimum(actualArgMin, out actualMinimum);
var expectedMinimum = 0.0;
Assert.That(actualMinimum, Is.EqualTo(expectedMinimum).Within(1E-2), "Minimum");
var expectedArgMin = Enumerable.Repeat(1.0, d).ToArray();
Assert.That(actualArgMin, Is.EqualTo(expectedArgMin).AsCollection.Within(1E-1));
}