//JAVA TO C# CONVERTER TODO TASK: Most Java annotations will not have direct .NET equivalent attributes:
//ORIGINAL LINE: @Test public void penaltyMatrix1DTest()
public virtual void penaltyMatrix1DTest()
{
int n = 10;
DoubleMatrix p0 = PenaltyMatrixGenerator.getPenaltyMatrix(n, 0); //zeroth order
AssertMatrix.assertEqualsMatrix(DoubleMatrix.identity(n), p0, 1e-15);
//constant
DoubleArray x = DoubleArray.filled(n, 2.0);
DoubleMatrix p = PenaltyMatrixGenerator.getPenaltyMatrix(n, 2);
double r = MA.getInnerProduct(x, MA.multiply(p, x));
assertEquals(0.0, r);
DoubleArray x2 = DoubleArray.of(n, i => i);
r = MA.getInnerProduct(x2, MA.multiply(p, x2));
assertEquals(0.0, r);
DoubleArray x3 = DoubleArray.of(n, i => 0.4 + 0.4 * i + i * i);
r = MA.getInnerProduct(x3, MA.multiply(p, x3));
//The second order diff is 2; for 2nd order difference use 8 values (n-2), so expect 8 * 2^2 = 32
assertEquals(32.0, r, 1e-11);
p = PenaltyMatrixGenerator.getPenaltyMatrix(n, 3);
r = MA.getInnerProduct(x3, MA.multiply(p, x3));
assertEquals(0.0, r, 1e-13);
}