public void EvalTest()
{
// Expected values calculated using Wolfram Alpha https://www.wolframalpha.com/
var f = new Polynomial(new double[] { 1, 2, 3 });
double fVal = f.EvaluateAt(1);
Assert.AreEqual(6, fVal, 0.1);
fVal = f.EvaluateAt(2);
Assert.AreEqual(17, fVal, 0.1);
fVal = f.EvaluateAt(3.415);
Assert.AreEqual(42.8167, fVal, 0.1);
fVal = f.EvaluateAt(-50.543);
Assert.AreEqual(7563.7, fVal, 0.1);
f = new Polynomial(new double[] { 83.23, 99.0, -92.23, 12, 13, 190 });
fVal = f.EvaluateAt(-9.345);
Assert.AreEqual(-1.3460527721401352e7, fVal, 0.0001);
fVal = f.EvaluateAt(0.0493);
Assert.AreEqual(87.8881, fVal, 0.0001);
}
public void MultiplicationTest()
{
// (1 + x + x^2)(2 + 3x) = (2 + 5x + 5x^2 + 3x^3)
var f = new Polynomial(new double[] { 1, 1, 1 });
var g = new Polynomial(new double[] { 2, 3 });
Polynomial result = f * g;
Assert.AreEqual(3, result.Degree);
Assert.AreEqual(2, result.Coefficients[0]);
Assert.AreEqual(5, result.Coefficients[1]);
Assert.AreEqual(5, result.Coefficients[2]);
Assert.AreEqual(3, result.Coefficients[3]);
// Degree 5: (2 + 4x^3 - 93x^5)
f = new Polynomial(new double[] { 2, 0, 0, 4, 0, -93 });
// Degree 17: (42x + 2.1x^17)
var gCoefficients = new double[18];
gCoefficients[1] = 42;
gCoefficients[17] = 2.1;
g = new Polynomial(gCoefficients);
// This should result in a degree 22 polynomial
// Expecting: -195.3 x^22 + 8.4 x^20 + 4.2 x^17 - 3906 x^6 + 168 x^4 + 84 x
result = f * g;
Assert.AreEqual(22, result.Degree);
Assert.AreEqual(-195.3, result.Coefficients[22]);
Assert.AreEqual(0, result.Coefficients[21]);
Assert.AreEqual(8.4, result.Coefficients[20]);
Assert.AreEqual(4.2, result.Coefficients[17]);
Assert.AreEqual(-3906, result.Coefficients[6]);
Assert.AreEqual(168, result.Coefficients[4]);
Assert.AreEqual(84, result.Coefficients[1]);
Assert.AreEqual(0, result.Coefficients[0]);
double val = result.EvaluateAt(0.5);
Assert.AreEqual(-8.53126, val, 0.0001);
Console.WriteLine(result);
}
