cusp::relaxation::jacobi< ValueType, MemorySpace > Class Template Reference

#include <jacobi.h>

Inheritance diagram for cusp::relaxation::jacobi< ValueType, MemorySpace >:

Public Methods
	jacobi (void)
template<typename MatrixType >
	jacobi (const MatrixType &A, ValueType omega=1.0)
template<typename MemorySpace2 >
	jacobi (const jacobi< ValueType, MemorySpace2 > &A)
template<typename MatrixType , typename VectorType1 , typename VectorType2 >
void	operator() (const MatrixType &A, const VectorType1 &b, VectorType2 &x)
template<typename MatrixType , typename VectorType1 , typename VectorType2 >
void	operator() (const MatrixType &A, const VectorType1 &b, VectorType2 &x, const ValueType omega)
Public Methods inherited from cusp::linear_operator< ValueType, MemorySpace, IndexType >
	linear_operator (void)
	linear_operator (IndexType num_rows, IndexType num_cols)
	linear_operator (IndexType num_rows, IndexType num_cols, IndexType num_entries)

Detailed description

template<typename ValueType, typename MemorySpace>
class cusp::relaxation::jacobi< ValueType, MemorySpace >

Represents a Jacobi relaxation scheme.

Template Parameters

ValueType	value_type of the array
MemorySpace	memory space of the array (cusp::host_memory or cusp::device_memory)

Overview

Extracts the matrix diagonal and performs weighted Jacobi relaxation

Example

#include <cusp/array1d.h>
#include <cusp/csr_matrix.h>
#include <cusp/monitor.h>
 
#include <cusp/blas/blas.h>
#include <cusp/linear_operator.h>
#include <cusp/gallery/poisson.h>
 
// include cusp Jacobi header file
#include <cusp/relaxation/jacobi.h>
 
int main()
{
   // Construct 5-pt Poisson example
   cusp::csr_matrix<int, float, cusp::device_memory> A;
   cusp::gallery::poisson5pt(A, 5, 5);
 
   // Initialize data
   cusp::array1d<float, cusp::device_memory> x(A.num_rows, 0);
   cusp::array1d<float, cusp::device_memory> b(A.num_rows, 1);
 
   // Allocate temporaries
   cusp::array1d<float, cusp::device_memory> r(A.num_rows);
 
   // Construct Jacobi relaxation class
   cusp::relaxation::jacobi<float, cusp::device_memory> M(A);
 
   // Compute initial residual
   cusp::multiply(A, x, r);
   cusp::blas::axpy(b, r, float(-1));
 
   // Construct monitor with stopping criteria of 100 iterations or 1e-4 residual error
   cusp::monitor<float> monitor(b, 100, 1e-4, 0, true);
 
   // Iteratively solve system
   while (!monitor.finished(r))
   {
       M(A, b, x);
       cusp::multiply(A, x, r);
       cusp::blas::axpy(b, r, float(-1));
       ++monitor;
   }
 }

Definition at line 95 of file jacobi.h.

Constructor & Destructor Documentation

jacobi() [1/3]

template<typename ValueType , typename MemorySpace >

cusp::relaxation::jacobi< ValueType, MemorySpace >::jacobi ( void  )

inline

This constructor creates an empty jacobi smoother.

Definition at line 107 of file jacobi.h.

jacobi() [2/3]

template<typename ValueType , typename MemorySpace >

template<typename MatrixType >

cusp::relaxation::jacobi< ValueType, MemorySpace >::jacobi	(	const MatrixType &	A,
		ValueType	omega = 1.0
	)

This constructor creates a jacobi smoother using a given matrix and sweeping strategy (FORWARD, BACKWARD, SYMMETRIC).

Template Parameters

MatrixType

Type of input matrix used to create this jacobi smoother.

Parameters

A	Input matrix used to create smoother.
omega	Damping factor used in Jacobi smoother.

jacobi() [3/3]

template<typename ValueType , typename MemorySpace >

template<typename MemorySpace2 >

cusp::relaxation::jacobi< ValueType, MemorySpace >::jacobi ( const jacobi< ValueType, MemorySpace2 > &  A )

inline

Copy constructor for jacobi smoother.

Template Parameters

MemorySpace2

Memory space of input jacobi smoother.

Parameters

A	Input jacobi smoother.

Definition at line 128 of file jacobi.h.

Member Function Documentation

operator()() [1/2]

template<typename ValueType , typename MemorySpace >

template<typename MatrixType , typename VectorType1 , typename VectorType2 >

void cusp::relaxation::jacobi< ValueType, MemorySpace >::operator()	(	const MatrixType &	A,
		const VectorType1 &	b,
		VectorType2 &	x
	)

Perform Jacobi relaxation using default omega damping factor specified during construction of this jacobi smoother

Template Parameters

MatrixType	Type of input matrix.
VectorType1	Type of input right-hand side vector.
VectorType2	Type of input approximate solution vector.

Parameters

A	matrix of the linear system
x	approximate solution of the linear system
b	right-hand side of the linear system

operator()() [2/2]

template<typename ValueType , typename MemorySpace >

template<typename MatrixType , typename VectorType1 , typename VectorType2 >

void cusp::relaxation::jacobi< ValueType, MemorySpace >::operator()	(	const MatrixType &	A,
		const VectorType1 &	b,
		VectorType2 &	x,
		const ValueType	omega
	)

Perform Jacobi relaxation using specified omega damping factor.

Template Parameters

MatrixType	Type of input matrix.
VectorType1	Type of input right-hand side vector.
VectorType2	Type of input approximate solution vector.

Parameters

A	matrix of the linear system
x	approximate solution of the linear system
b	right-hand side of the linear system
omega	Damping factor used in Jacobi smoother.