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Polynomial: no longer clone and normalize at creation

ridge-regression
Christoph Ruegg 8 years ago
parent
70795dbcb8
commit
5eb1924988
2 changed files with 86 additions and 80 deletions
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  1. 70
      src/Numerics.Tests/PolynomialTests.cs
  2. 96
      src/Numerics/Polynomial.cs

70
src/Numerics.Tests/PolynomialTests.cs
View File

@ -218,25 +218,25 @@ namespace MathNet.Numerics.UnitTests
Assert.Throws(typeof(DivideByZeroException), () =>
{
var p1 = new Polynomial(1.0d);
var p2 = new Polynomial(new double[0]);
var p2 = new Polynomial();
GC.KeepAlive(Polynomial.DivideRemainder(p1, p2));
});
Assert.DoesNotThrow(() =>
{
var p1 = new Polynomial(new double[0]);
var p1 = new Polynomial();
var p2 = new Polynomial(1.0d);
GC.KeepAlive(Polynomial.DivideRemainder(p1, p2));
});
Assert.Throws(typeof(DivideByZeroException), () =>
{
var p1 = new Polynomial(new double[0]);
var p2 = new Polynomial(new double[0]);
var p1 = new Polynomial();
var p2 = new Polynomial();
GC.KeepAlive(Polynomial.DivideRemainder(p1, p2));
});
Assert.Throws(typeof(DivideByZeroException), () =>
{
var p1 = new Polynomial(1.0d);
var p2 = new Polynomial(0.0d);
var p2 = new Polynomial();
GC.KeepAlive(Polynomial.DivideRemainder(p1, p2));
});
}
@ -250,7 +250,7 @@ namespace MathNet.Numerics.UnitTests
TestEqual(new double[] { 1.0 }, tpl1.Item1);
TestEqual(new double[0], tpl1.Item2);
var p12 = new Polynomial(new double[] { 2.0d, 2.0d });
var p12 = new Polynomial(2.0d, 2.0d);
var p22 = new Polynomial(2.0d);
var tpl2 = Polynomial.DivideRemainder(p12, p22);
TestEqual(new double[] { 1.0, 1.0 }, tpl2.Item1);
@ -292,7 +292,7 @@ namespace MathNet.Numerics.UnitTests
Assert.AreEqual(0, r.Length, "length mismatch");
// 0 = 1 + 2*x -> single root at -1/2
var p2 = new Polynomial(new double[] { 1, 2 });
var p2 = new Polynomial(1, 2);
var r2 = p2.Roots();
Assert.AreEqual(1, r2.Length, "length mismatch");
Assert.AreEqual(-0.5, r2.FirstOrDefault().Real, tol);
@ -304,27 +304,44 @@ namespace MathNet.Numerics.UnitTests
var x_2 = new double[] { -1.0, 1.0 };
var expected_2 = new List<Complex>();
expected_2.Add(new Complex(1.0, 0.0));
TestEqual(x_2, expected_2);
TestRootsEqual(x_2, expected_2);
var x_3 = new double[] { -1.0, 0.0, 1.0 };
var expected_3 = new List<Complex>();
expected_3.Add(new Complex(1.0, 0.0));
expected_3.Add(new Complex(-1.0, 0.0));
TestEqual(x_3, expected_3);
TestRootsEqual(x_3, expected_3);
var x_4 = new double[] { -1.0, -0.33333333333333337, 0.33333333333333326, 1.0 };
var expected_4 = new List<Complex>();
expected_4.Add(new Complex(0.9999999999999996, 0.0));
expected_4.Add(new Complex(-0.6666666666666666, 0.7453559924999296));
expected_4.Add(new Complex(-0.6666666666666666, -0.7453559924999296));
TestEqual(x_4, expected_4);
TestRootsEqual(x_4, expected_4);
}
static void TestRootsEqual(double[] x, List<Complex> eIn)
{
var tol = 1e-10;
var r0 = new Polynomial(x).Roots().ToList();
var e = eIn.OrderBy(v => v.Real).ToArray();
var r = r0.OrderBy(v => v.Real).ToArray();
Assert.IsNotNull(r);
Assert.AreEqual(e.Length, r.Length, "Length mismatch");
for (int k = 0; k < r.Length; k++)
{
var msg = String.Format("At k={0}", k);
Assert.AreEqual(e[k].Real, r[k].Real, tol, msg);
Assert.AreEqual(e[k].Imaginary, r[k].Imaginary, tol, msg);
}
}
[Test]
public void DataContractSerializationTest()
{
Polynomial expected = new Polynomial(new [] { 1.0d, 2.0d, 0.0d, 3.0d });
expected.VariableName = "z";
Polynomial expected = new Polynomial(1.0d, 2.0d, 0.0d, 3.0d) { VariableName = "z" };
var serializer = new DataContractSerializer(typeof(Polynomial));
var stream = new MemoryStream();
@ -339,27 +356,9 @@ namespace MathNet.Numerics.UnitTests
Assert.That(actual, Is.Not.SameAs(expected));
}
static void TestEqual(double[] x, List<Complex> eIn)
{
var tol = 1e-10;
var r0 = new Polynomial(x).Roots().ToList();
var e = eIn.OrderBy(v => v.Real).ToArray();
var r = r0.OrderBy(v => v.Real).ToArray();
Assert.IsNotNull(r);
Assert.AreEqual(e.Length, r.Length, "length mismatch");
for (int k = 0; k < r.Length; k++)
{
var msg = String.Format("At k={0}", k);
Assert.AreEqual(e[k].Real, r[k].Real, tol, msg);
Assert.AreEqual(e[k].Imaginary, r[k].Imaginary, tol, msg);
}
}
static void TestEqual(double[] p_tar, double[] p_res, string msg = null)
{
Assert.AreEqual(p_tar.Length, p_res.Length, "length mismatch");
Assert.AreEqual(p_tar.Length, p_res.Length, "Length mismatch");
for (int k = 0; k < p_res.Length; k++)
{
Assert.AreEqual(p_tar[k], p_res[k], msg);
@ -368,18 +367,17 @@ namespace MathNet.Numerics.UnitTests
static void TestEqual(double[] p_tar, Polynomial p_res, string msg = null)
{
Assert.AreEqual(p_tar.Length, p_res.Coefficients.Length, "length mismatch");
for (int k = 0; k < p_res.Coefficients.Length; k++)
Assert.AreEqual(p_tar.Length, p_res.Degree + 1, "Degree mismatch");
for (int k = 0; k <= p_res.Degree; k++)
{
Assert.AreEqual(p_tar[k], p_res.Coefficients[k], msg);
}
}
static void TestEqual(Polynomial p_tar, Polynomial p_res, string msg = null)
{
Assert.AreEqual(p_tar.Coefficients.Length, p_res.Coefficients.Length, "length mismatch");
for (int k = 0; k < p_res.Coefficients.Length; k++)
Assert.AreEqual(p_tar.Degree, p_res.Degree, "Degree mismatch");
for (int k = 0; k <= p_res.Degree; k++)
{
Assert.AreEqual(p_tar.Coefficients[k], p_res.Coefficients[k], msg);
}

96
src/Numerics/Polynomial.cs
View File

@ -23,6 +23,9 @@ namespace MathNet.Numerics
[Serializable]
[DataContract(Namespace = "urn:MathNet/Numerics")]
public class Polynomial : IFormattable, IEquatable<Polynomial>
#if !NETSTANDARD1_3
, ICloneable
#endif
{
/// <summary>
/// The coefficients of the polynomial in a
@ -79,11 +82,9 @@ namespace MathNet.Numerics
/// Example: {5, 0, 2} -> "p : x -> 5 + 0 x^1 + 2 x^2".
/// </summary>
/// <param name="coefficients">Polynomial coefficients as array</param>
public Polynomial(double[] coefficients)
public Polynomial(params double[] coefficients)
{
int degree = EvaluateDegree(coefficients);
Coefficients = new double[degree + 1];
Array.Copy(coefficients, Coefficients, Coefficients.Length);
Coefficients = coefficients;
}
/// <summary>
@ -117,22 +118,6 @@ namespace MathNet.Numerics
return new Polynomial(coefficients);
}
/// <summary>
/// This method returns the coefficients of the Polynomial as an array the "IsFlipped" property,
/// which is set during construction is taken into account automatically.
/// </summary>
/// <returns>The coefficients of the polynomial as an array</returns>
public double[] ToArray()
{
return Coefficients.ToArray();
}
public object Clone()
{
// TODO: this assumes the constructor does a copy
return new Polynomial(Coefficients);
}
#region Evaluation
/// <summary>
/// Evaluate a polynomial at point x.
@ -415,29 +400,23 @@ namespace MathNet.Numerics
/// <returns>Resulting Polynomial</returns>
public static Polynomial Multiply(Polynomial a, Polynomial b)
{
var aa = a.Clone() as Polynomial;
var bb = b.Clone() as Polynomial;
// do not cut trailing zeros, since it may corrupt the outcom, if the array is of form 1 + x^-1 + x^-2 + x^-3
//a.Trim();
//b.Trim();
var ad = a.Degree;
var bd = b.Degree;
double[] ac = a.Coefficients;
double[] bc = b.Coefficients;
double[] a1 = aa.Coefficients;
double[] b1 = bb.Coefficients;
double[] ret = new double[a1.Length + b1.Length];
var degree = ad + bd;
double[] result = new double[degree + 1];
for (int i = 0; i < a1.Length; i++)
for (int i = 0; i <= ad; i++)
{
for (int j = 0; j < b1.Length; j++)
for (int j = 0; j <= bd; j++)
{
ret[i + j] += a1[i] * b1[j];
result[i + j] += ac[i] * bc[j];
}
}
Polynomial result = new Polynomial(ret);
//ret_p.Trim();
return result;
return new Polynomial(result);
}
/// <summary>
@ -448,12 +427,15 @@ namespace MathNet.Numerics
/// <returns>Resulting Polynomial</returns>
public static Polynomial Multiply(Polynomial a, double k)
{
var aa = a.Clone() as Polynomial;
var ac = a.Coefficients;
for (int ii = 0; ii < aa.Coefficients.Length; ii++)
aa.Coefficients[ii] *= k;
var result = new double[a.Degree + 1];
for (int i = 0; i < result.Length; i++)
{
result[i] = ac[i] * k;
}
return aa;
return new Polynomial(result);
}
/// <summary>
@ -464,12 +446,15 @@ namespace MathNet.Numerics
/// <returns>Resulting Polynomial</returns>
public static Polynomial Divide(Polynomial a, double k)
{
var aa = a.Clone() as Polynomial;
var ac = a.Coefficients;
for (int ii = 0; ii < aa.Coefficients.Length; ii++)
aa.Coefficients[ii] /= k;
var result = new double[a.Degree + 1];
for (int i = 0; i < result.Length; i++)
{
result[i] = ac[i] / k;
}
return aa;
return new Polynomial(result);
}
/// <summary>
@ -968,5 +953,28 @@ namespace MathNet.Numerics
return hash;
}
#endregion
#region
public Polynomial Clone()
{
int degree = EvaluateDegree(Coefficients);
var coefficients = new double[degree + 1];
Array.Copy(Coefficients, coefficients, coefficients.Length);
return new Polynomial(coefficients);
}
#if !NETSTANDARD1_3
/// <summary>
/// Creates a new object that is a copy of the current instance.
/// </summary>
/// <returns>
/// A new object that is a copy of this instance.
/// </returns>
object ICloneable.Clone()
{
return Clone();
}
#endif
#endregion
}
}

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