NOX::Petsc::Group Class Reference

Concrete implementation of NOX::Abstract::Group for Petsc. More...

#include <NOX_Petsc_Group.H>

Inheritance diagram for NOX::Petsc::Group:

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Collaboration diagram for NOX::Petsc::Group:
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List of all members.

Public Member Functions

 Group (Interface &i, Vec &x, Mat &J)
 Constructor.
 Group (const Group &source, CopyType type=DeepCopy)
 Copy constructor. If type is DeepCopy, takes ownership of valid shared Jacobian.
virtual ~Group ()
 Destructor.
virtual Abstract::Groupoperator= (const NOX::Abstract::Group &source)
 Copies the source group into this group.
virtual Abstract::Groupoperator= (const Group &source)
 See above.
virtual Teuchos::RefCountPtr<
NOX::Abstract::Group
clone (CopyType type=DeepCopy) const
"Compute" functions.
virtual void setX (const Vector &y)
virtual void setX (const Abstract::Vector &y)
 See above.
virtual void computeX (const Group &grp, const Vector &d, double step)
virtual void computeX (const Abstract::Group &grp, const Abstract::Vector &d, double step)
 See above.
virtual Abstract::Group::ReturnType computeF ()
 Compute and store F(x).
virtual Abstract::Group::ReturnType computeJacobian ()
 Compute and store Jacobian.
virtual Abstract::Group::ReturnType computeGradient ()
 Compute and store gradient.
virtual Abstract::Group::ReturnType computeNewton (Teuchos::ParameterList &params)
 Compute the Newton direction, using parameters for the linear solve.
Jacobian operations.
Operations using the Jacobian matrix. These may not be defined in matrix-free scenarios.

virtual Abstract::Group::ReturnType applyJacobian (const Vector &input, Vector &result) const
virtual Abstract::Group::ReturnType applyJacobian (const Abstract::Vector &input, Abstract::Vector &result) const
 See above.
virtual Abstract::Group::ReturnType applyJacobianTranspose (const Vector &input, Vector &result) const
virtual Abstract::Group::ReturnType applyJacobianTranspose (const Abstract::Vector &input, Abstract::Vector &result) const
 See above.
virtual Abstract::Group::ReturnType applyRightPreconditioning (const Vector &input, Vector &result) const
 Preconditions a vector using one of the available methods in Petsc.
virtual Abstract::Group::ReturnType applyRightPreconditioning (Teuchos::ParameterList &, const Abstract::Vector &input, Abstract::Vector &result) const
 See above.
"Is" functions
Checks to see if various objects have been computed. Returns true if the corresponding "compute" function has been called since the last update to the solution vector (via instantiation or computeX).

virtual bool isF () const
 Return true if F is valid.
virtual bool isJacobian () const
 Return true if the Jacobian is valid.
virtual bool isGradient () const
 Return true if the gradient is valid.
virtual bool isNewton () const
 Return true if the Newton direction is valid.
virtual bool isPreconditioner () const
"Get" functions
Note that these function do not check whether or not the vectors are valid. Must use the "Is" functions for that purpose.

virtual const Abstract::VectorgetX () const
 Return solution vector.
virtual const Abstract::VectorgetF () const
 Return F(x).
virtual double getNormF () const
 Return 2-norm of F(x).
virtual const Abstract::VectorgetGradient () const
 Return gradient.
virtual const Abstract::VectorgetNewton () const
 Return Newton direction.

Protected Member Functions

virtual void resetIsValid ()
 resets the isValid flags to false

Protected Attributes

double normRHS
 Norm of RHS.
SharedJacobiansharedJacobianPtr
 Pointer to shared Jacobian matrix.
SharedJacobiansharedJacobian
 Reference to shared Jacobian matrix.
string jacType
 Specification of Jacobian Type.
InterfaceuserInterface
 Reference to the user supplied interface functions.
Vectors
Vector xVector
 Solution vector.
Vector RHSVector
 Right-hand-side vector (function evaluation).
Vector gradVector
 Gradient vector (steepest descent vector).
Vector NewtonVector
 Newton direction vector.
IsValid flags
True if the current solution is up-to-date with respect to the currect xVector.

bool isValidRHS
bool isValidJacobian
bool isValidGrad
bool isValidNewton
bool isValidPreconditioner

Detailed Description

Concrete implementation of NOX::Abstract::Group for Petsc.


Member Function Documentation

Abstract::Group::ReturnType Group::applyRightPreconditioning const Vector input,
Vector result
const [virtual]
 

Preconditions a vector using one of the available methods in Petsc.

Currently, the preconditioning method corresponds to whatever is available in the user's Petsc installation and is specified in the local .petscrc file. For example, a direct solve can be accomplished by specifying -pc_type lu (serial only), whereas diagonal scaling can be achieved via -pc_type jacobi.

Abstract::Group::ReturnType Group::computeF  )  [virtual]
 

Compute and store F(x).

Note:
It's generally useful to also compute and store the 2-norm of F(x) at this point for later access by the getNormF() function.
Returns:

Implements NOX::Abstract::Group.

Abstract::Group::ReturnType Group::computeGradient  )  [virtual]
 

Compute and store gradient.

We can pose the nonlinear equation problem $F(x) = 0$ as an optimization problem as follows:

\[ \min f(x) \equiv \frac{1}{2} \|F(x)\|_2^2. \]

In that case, the gradient (of $f$) is defined as

\[ g \equiv J^T F. \]

Returns:

Reimplemented from NOX::Abstract::Group.

Abstract::Group::ReturnType Group::computeJacobian  )  [virtual]
 

Compute and store Jacobian.

Recall that

\[ F(x) = \left[ \begin{array}{c} F_1(x) \\ F_2(x) \\ \vdots \\ F_n(x) \\ \end{array} \right]. \]

The Jacobian is denoted by $J$ and defined by

\[ J_{ij} = \frac{\partial F_i}{\partial x_j} (x). \]

Note:
If this is a shared object, this group should taken ownership of the Jacobian before it computes it.
Returns:

Reimplemented from NOX::Abstract::Group.

Abstract::Group::ReturnType Group::computeNewton Teuchos::ParameterList params  )  [virtual]
 

Compute the Newton direction, using parameters for the linear solve.

The Newton direction is the solution, s, of

\[ J s = -F. \]

The parameters are from the "Linear %Solver" sublist of the "Direction" sublist that is passed to solver during construction.

The "Tolerance" parameter may be added/modified in the sublist of "Linear Solver" parameters that is passed into this function. The solution should be such that

\[ \frac{\| J s - (-F) \|_2}{\max \{ 1, \|F\|_2\} } < \mbox{Tolerance} \]

Returns:

Reimplemented from NOX::Abstract::Group.

double Group::getNormF  )  const [virtual]
 

Return 2-norm of F(x).

In other words,

\[ \sqrt{\sum_{i=1}^n F_i^2} \]

Implements NOX::Abstract::Group.

bool Group::isGradient  )  const [virtual]
 

Return true if the gradient is valid.

Note:
Default implementation in NOX::Abstract::Group returns false.

Reimplemented from NOX::Abstract::Group.

bool Group::isJacobian  )  const [virtual]
 

Return true if the Jacobian is valid.

Note:
Default implementation in NOX::Abstract::Group returns false.

Reimplemented from NOX::Abstract::Group.

bool Group::isNewton  )  const [virtual]
 

Return true if the Newton direction is valid.

Note:
Default implementation in NOX::Abstract::Group returns false.

Reimplemented from NOX::Abstract::Group.

Abstract::Group & Group::operator= const NOX::Abstract::Group source  )  [virtual]
 

Copies the source group into this group.

Note:
Any shared data owned by the source should have its ownership transfered to this group. This may result in a secret modification to the source object.

Implements NOX::Abstract::Group.


The documentation for this class was generated from the following files:
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