private static float[] GenerateX(float a, float b, float step)
{
int pointCount = ChebyshevApproximation.CalculateRank(a, b, step);
var result = new float[pointCount];
for (int i = 0; i < pointCount; i++)
{
result[i] = a + i * step;
}
return(result);
}
public void Approximate()
{
float a = -2.0f;
float b = 2.0f;
float step = 0.5f;
int rank = ChebyshevApproximation.CalculateRank(a, b, step);
var polynom = ChebyshevApproximation.Approximate(a, b, rank, myFunc);
List <float> results = new List <float>();
var xApprox = GenerateX(a, b, 0.0001f);
for (float i = a; i <= b; i += 0.0001f)
{
float x = ChebyshevApproximation.Squish(i, a, b);
results.Add(ChebyshevApproximation.Evaluate(polynom, x));
}
Assert.That(polynom.Length == rank + 1);
}
public void CompareTableAndFunc()
{
float a = -2.0f;
float b = 2.0f;
float step = 0.5f;
int rank = ChebyshevApproximation.CalculateRank(a, b, step);
var xValues = GenerateX(a, b, step);
var yValues = new float[rank];
for (int i = 0; i < rank; i++)
{
yValues[i] = (float)myFunc(xValues[i]);
}
var expectedCoefficients = new Matrix(ChebyshevApproximation.Approximate(a, b, rank - 1, myFunc));
var actualCoefficients = new Matrix(ChebyshevApproximation.Approximate(xValues, yValues, xValues.Length - 1));
Assert.That(actualCoefficients.NearEquals(expectedCoefficients, (float)Math.PI + 0.2f), $"Expected: {expectedCoefficients.ToString()}, actual {actualCoefficients.ToString()}");
}
private void DrawMSE_Func()
{
var rank = ChebyshevApproximation.CalculateRank(a, b, step);
var xValues = new Libs.Matrix(ChebyshevApproximation.GenerateX(a, b, step));
var yValues = new Libs.Matrix(new float[rank, 1]);
for (int j = 0; j < yValues.Height; j++)
{
yValues[j, 0] = (float)ApproximatedFunction(xValues[0, j]);
}
var coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 1);
MnkK1Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 2);
MnkK2Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 3);
MnkK3Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 4);
MnkK4Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 5);
MnkK5Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 6);
MnkK6Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 7);
MnkK7Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 8);
MnkK8Plotter.ItemsSource = GeneratePoints(coefs);
coefs = MeanSquaredErrorApproximation.Approximate(xValues, yValues, 9);
MnkK9Plotter.ItemsSource = GeneratePoints(coefs);
}