Constructor Detail

• IterativeLinearSolverEvent

  public IterativeLinearSolverEvent(Object source,
                            int iterations)

  Creates a new instance of this class.

  Parameters:

  source - the iterative algorithm on which the event initially occurred

  iterations - the number of iterations performed at the time this event is created

Method Detail

• getRightHandSideVector

  public abstract RealVector getRightHandSideVector()

  Returns the current right-hand side of the linear system to be solved. This method should return an unmodifiable view, or a deep copy of the actual right-hand side vector, in order not to compromise subsequent iterations of the source IterativeLinearSolver.

  Returns:

  the right-hand side vector, b

• getNormOfResidual

  public abstract double getNormOfResidual()

  Returns the norm of the residual. The returned value is not required to be exact. Instead, the norm of the so-called updated residual (if available) should be returned. For example, the conjugate gradient method computes a sequence of residuals, the norm of which is cheap to compute. However, due to accumulation of round-off errors, this residual might differ from the true residual after some iterations. See e.g. A. Greenbaum and Z. Strakos, Predicting the Behavior of Finite Precision Lanzos and Conjugate Gradient Computations, Technical Report 538, Department of Computer Science, New York University, 1991 (available here).

  Returns:

  the norm of the residual, ||r||

• getResidual

  public RealVector getResidual()

  Returns the residual. This is an optional operation, as all iterative linear solvers do not provide cheap estimate of the updated residual vector, in which case

  • this method should throw a MathUnsupportedOperationException,
  • providesResidual() returns false.

  The default implementation throws a MathUnsupportedOperationException. If this method is overriden, then providesResidual() should be overriden as well.

  Returns:

  the updated residual, r

• getSolution

  public abstract RealVector getSolution()

  Returns the current estimate of the solution to the linear system to be solved. This method should return an unmodifiable view, or a deep copy of the actual current solution, in order not to compromise subsequent iterations of the source IterativeLinearSolver.

  Returns:

  the solution, x

• providesResidual

  public boolean providesResidual()

  Returns true if getResidual() is supported. The default implementation returns false.

  Returns:

  false if getResidual() throws a MathUnsupportedOperationException