A class for representing a general multi-point constraint equation. More...

#include <mpc.hh>

Classes
struct	DOF
	A struct for representing one term (DOF number and associated coefficient) in a MPC equation. More...

class	Less
	Comparison predicate for MPCs. More...

Public Member Functions
	MPC (int n, int d, double c=double(0))
	Constructor creating a constraint for a specified slave DOF with no master DOFs. More...

void	addMaster (int n, int d, double c=double(1), double tol=double(1.0e-8))
	Adds a master DOF to the constraint equation. More...

void	updateMaster (size_t pos, double c)
	Updates the coefficient of the pos'th master DOF. More...

void	removeMaster (size_t pos)
	Removes the pos'th master DOF from the constraint equation. More...

void	addOffset (double offset)
	Increments the c0 coefficient by a given offset. More...

void	setSlaveCoeff (double c0)
	Assigns a new c0 coefficient to the constraint equation. More...

const DOF &	getSlave () const
	Returns a reference to the slave DOF. More...

const DOF &	getMaster (size_t i) const
	Returns a reference to the i'th master DOF. More...

size_t	getNoMaster () const
	Returns the number of master DOFs. More...

Public Attributes
int	iceq
	Global constraint equation identifier. More...

Friends
std::ostream &	operator<< (std::ostream &s, const MPC &mpc)
	Global stream operator printing a constraint equation. More...

Detailed Description

A class for representing a general multi-point constraint equation.

A multi-point constraint (MPC) equation is used to introduce additional coupling between the degrees of freedom (DOF) in a FE grid.

An MPC equation is in general a linear coupling of one (slave) dof to a set of master dofs, and may be expressed as

$s = c_0 + c_1 m_1 + c_2 m_2 + \ldots + c_n m_n$

where

denotes the slave dof
is the value of the slave dof when all master dofs are zero, or when there are no masters in the equation (prescribed dof).
is a master dof
is a constant scaling coefficient associated with the i'th master
n denotes the total number of master dofs in the equation

When n = 0, the above equation represents a fixed ( $c_0=0$ ) or prescribed ( $c_0\ne0$ ) dof.

One or more of the master dofs may also be a slave in another constraint equation (chained constrains). In this case the two equations are combined to eliminate the master dof that is constrained. This is done while preprocessing the model by the resolveMPCchains function.

Constructor & Destructor Documentation

Opm::Elasticity::MPC::MPC	(	int	n,
		int	d,
		double	c = `double(0)`
	)

inline

Constructor creating a constraint for a specified slave DOF with no master DOFs.

Parameters

[in]	n	The node number of the slave DOF (1...NNOD)
[in]	d	The local DOF number of the slave DOF (1...3)
[in]	c	The actual value that this slave DOF is constrained to when there are no master DOFs, or all master DOFs are zero

References iceq.

Member Function Documentation

void Opm::Elasticity::MPC::addMaster	(	int	n,
		int	d,
		double	c = `double(1)`,
		double	tol = `double(1.0e-8)`
	)

inline

Adds a master DOF to the constraint equation.

Parameters

[in]	n	The node number of the master DOF (1...NNOD)
[in]	d	The local DOF number of the master DOF (1...3)
[in]	c	The coefficient that this master should be scaled with
[in]	tol	Tolerance for comparison with zero, if the coefficient c is zero, the master DOF is not added