class HCL_CG_d : public HCL_LinearSolver_d

HCL_CG_d implements the (unpreconditioned) conjugate gradients algorithm for solving a linear operator equation with a symmetric positive definite operator

Inheritance:

Public Methods

	HCL_CG_d ( char *fname = NULL, HCL_Recorder_d * rec = NULL) Constructor
Table&	Parameters () const Access to parameter table
virtual int	Solve ( const HCL_LinearOp_d & A, const HCL_Vector_d & b, HCL_Vector_d & x ) const Solve (approximately) the equation Ax=b for x
virtual ostream&	Write ( ostream & str ) const Prints description of the object

Public

	Input Parameters double Tol Stopping criteria int MaxItn Maximum number of iterations int DispFlag Display level
	Output parameters double ResidualNorm Norm of the residual error int TermCode Termination code

Inherited from HCL_LinearSolver_d:

Inherited from HCL_Base:

Public Methods

void IncCount() const

void DecCount() const

int Count() const

HCL_CG_d( char *fname = NULL, HCL_Recorder_d * rec = NULL)

Constructor.

Parameters:

fname - Parameter file name, or NULL
rec - Optional (pointer to) Recorder object

Table& Parameters() const

Access to parameter table. Algorithmic parameters can be accessed with Parameters().GetValue("NAME",val) or changed with Parameters().PutValue("NAME",val).

virtual int Solve( const HCL_LinearOp_d & A, const HCL_Vector_d & b, HCL_Vector_d & x ) const

Solve (approximately) the equation Ax=b for x

Returns:

The value of TermCode (see the Parameters section of this document.)

Parameters:

A - Linear operator
b - RHS vector
x - Initially, this must be a starting vector for the iteration. On exit, this contains the approximate solution

virtual ostream& Write( ostream & str ) const

Prints description of the object

Input Parameters

In a parameter file, the names may be prepended by "LinearSolver::", "LinearSolverCG::" or "CG::"

double Tol

Stopping criteria. The algorithm will terminate when the relative error is less than Tol. A value of 0.0 will imply a tolerance of 500*(machine epsilon).
Default = 1.0e-3

int MaxItn

Maximum number of iterations.
Default = 100

int DispFlag

Display level. This determines how much information should be displayed during the execution of the algorithm. Common values are:
0 - No output
1 - One-line summary output
2 - Detailed header and footer with timing information
3 - Per-iteration information

Default = 0

Output parameters

double ResidualNorm

Norm of the residual error

int TermCode

Termination code. Value is one of:

0 - Success
1 - Too many iterations taken

alphabetic index hierarchy of classes

this page has been generated automatically by doc++

(c)opyright by Malte Zöckler, Roland Wunderling
contact: doc++@zib.de