public void TestSecondPartial(double[] arr, double[] expected)
{
Derivative = new Derivative(TypicalMultivariateFunction);
var vector = new Vector(arr);
var joinedResult = new double[4];
for (int i = 0; i < 2; i++)
{
for (int j = 0; j < 2; j++)
{
joinedResult[2 * i + j] = Derivative.GetSecondPartialDerivative(vector, i, j);
}
}
Assert.AreEqual(expected, joinedResult);
}