[BUG] ResidualStopCriterion fails if iterative solver is solved for zero vector.

[wo80]

mathnet-numerics/src/Numerics/LinearAlgebra/Solvers/ResidualStopCriterion.cs

Line 198 in d96a65f

if (residualNorm < stopCriterion)

The comparision should actually be "less or equal". The following code will throw a NumericalBreakdownException:

var A = new DenseMatrix(2, 2, new double[] { 1, 2, 3, 4 });
var b = new DenseVector(2); // zero vector!
var x = new DenseVector(2);

var iterator = new Iterator<double>(new ResidualStopCriterion<double>(1e-5));
var solver = new BiCgStab();

solver.Solve(A, b, x, iterator, null);

[cdrnet]

Thank you!