Minotaur::Function Class Reference

#include <Function.h>

Public Member Functions
	Function ()
	Default constructor.
	Function (LinearFunctionPtr lf)
	Construct a function using only a linear function.
	Function (LinearFunctionPtr lf, QuadraticFunctionPtr qf)
	Function (LinearFunctionPtr lf, NonlinearFunctionPtr nlf)
	Construct a function using a linear function and a nonlinear function.
	Function (LinearFunctionPtr lf, QuadraticFunctionPtr qf, NonlinearFunctionPtr nlf)
	Function (NonlinearFunctionPtr nlf)
	Construct a function using only a nonlinear function.
virtual	~Function ()
	Destroy.
virtual FunctionPtr	cloneWithVars (VariableConstIterator vbeg, int *err) const
virtual FunctionPtr	cloneWithVarsPermute (VariableConstIterator vbeg, UIntVector variableaddress, int *err) const
	similar to above function, but for shuffling variables
virtual double	eval (const DoubleVector &x, int *error) const
virtual double	eval (const double *x, int *error) const
	Evaluate the function at a given point x.
virtual void	prepJac ()
virtual void	evalGradient (const double *x, double *grad_f, int *error) const
virtual void	fillJac (const double *x, double *values, int *error)
virtual UInt	getNumNzInHess ()
virtual bool	hasVar (VariablePtr var) const
virtual FunctionType	getType ()
bool	isLinearIn (ConstVariablePtr v)
	Check if function is linear in a variable. More...
virtual FunctionType	getVarFunType (ConstVariablePtr v)
virtual LinearFunctionPtr	getLinearFunction () const
	Return the linear part of the function.
virtual QuadraticFunctionPtr	getQuadraticFunction () const
	Return the quadratic part of the function.
virtual NonlinearFunctionPtr	getNonlinearFunction () const
	Return the nonlinear part of the function.
VarSetConstIterator	varsBegin ()
	Return a begin-iterator for the variables that are in this function.
VarSetConstIterator	varsEnd ()
	Return an end-iterator for the variables that are in this function.
virtual UInt	getNumVars () const
	Return the number of variables that are in this function.
virtual void	evalHessian (const double mult, const double *x, const size_t *offset, double *values, int *error)
virtual void	evalHessian (double mult, const double *x, const LTHessStor *stor, double *values, int *error)
virtual void	fillHessOffset (size_t *offset, size_t &pos, std::set< ConstVariablePair, CompareVariablePair > &v_pairs)
	Fill in the values of offset, starting from position pos.
virtual void	fillHessStor (LTHessStor *stor)
virtual void	finalHessStor (const LTHessStor *stor)
virtual void	changeLf (LinearFunctionPtr lf)
	Change the linear function part.
virtual void	changeNlf (NonlinearFunctionPtr nlf)
	Change the nonlinear function part.
virtual void	subst (VariablePtr out, VariablePtr in, double rat)
	Substitute a variable with another.
virtual void	operator*= (const double c)
QuadraticFunctionPtr	removeQuadratic ()
LinearFunctionPtr	removeLinear ()
NonlinearFunctionPtr	removeNonlinear ()
void	add (ConstLinearFunctionPtr lPtr)
void	removeVar (VariablePtr v, double val)
double	getFixVarOffset (VariablePtr v, double val)
virtual void	write (std::ostream &out) const
	Express the function and send the output to the output stream "out".

Protected Attributes
FunctionType	type_
	The type of the function.
VariableSet	vars_
	The variables that occur in this function.

Friends
std::ostream &	operator<< (std::ostream &out, const Function &f)
	Express the function and send the output to the output stream "out".

Detailed Description

The class Function is meant to model functions that are used to specify constraints and objectives in a problem. A function can have three or more components: linear, quadratic and nonlinear. Each of these types is implemented as a separate class. A Function thus keeps a pointer to each of these components and has methods to consolidate methods of these components. For instance, a function evaluation will just call these evaluation routines of the components and add them together. If any of the individual components of a function (linear, quadratic, nonlinear) are modified, one should delete the existing function and create a new one as some of the data-structures may not get updated with the changes.

Constructor & Destructor Documentation

Function() [1/2]

Function::Function	(	LinearFunctionPtr	lf,
		QuadraticFunctionPtr	qf
	)

Construct a function using a linear function and a quadratic function.

Function() [2/2]

Function::Function	(	LinearFunctionPtr	lf,
		QuadraticFunctionPtr	qf,
		NonlinearFunctionPtr	nlf
	)

Construct a function using a linear function, a quadratic function and a nonlinear function.

Member Function Documentation

add()

void Function::add

(

ConstLinearFunctionPtr

lPtr

)

Add a linear function. If the function already has a linear function, the new function is algebraically added, otherwise the new function is cloned.

cloneWithVars()

FunctionPtr Function::cloneWithVars ( VariableConstIterator  vbeg, int *  err  ) const

virtual

Make a clone using new variables. vbeg points to the variable id 0. vbeg+k points to variable id k, where k>=0.

eval()

double Function::eval ( const DoubleVector &  x, int *  error  ) const

virtual

Evaluate the function at a given point x. error must be zero if no errors were encountered.

evalGradient()

void Function::evalGradient ( const double *  x, double *  grad_f, int *  error  ) const

virtual

Evaluate Gradient at the given point x and fill in the array grad_f.

evalHessian()

void Function::evalHessian ( const double  mult, const double *  x, const size_t *  offset, double *  values, int *  error  )

virtual

Evaluate the hessian at a given point 'x'. Multiply the evaluated values by the lagrangean multiplier 'mult' and add the given matrix to the existing values in 'values'

getNumNzInHess()

UInt Function::getNumNzInHess ( )

virtual

Get number of terms in the hessian of the function. We only count terms that are nonzero in the lower-triangular half (including the diagonal) of the hessian matrix.

getType()

FunctionType Function::getType ( )

virtual

Return the type of a function: linear, quadratic, nonlinear etc. If the return type is quadratic, we may still have a linear component.

hasVar()

bool Function::hasVar ( VariablePtr  var ) const

virtual

Return true if variable var is one of the arguments of this function. Return false otherwise.

isLinearIn()

bool Function::isLinearIn

(

ConstVariablePtr

v

)

Check if function is linear in a variable.

Parameters

[in]

v

The variable that we want to test.

Returns

True if this function is linear or constant in variable v.

operator*=()

void Function::operator*= ( const double  c )

virtual

Multiply with a constant. If c is zero, then function becomes empty. We make the components NULL in such a case

removeLinear()

LinearFunctionPtr Function::removeLinear

(

)

Remove the linear part of the function and return a pointer to the linear part.

removeNonlinear()

NonlinearFunctionPtr Function::removeNonlinear

(

)

Remove the nonlinear part of the function and return a pointer to the nonlinear part.

removeQuadratic()

QuadraticFunctionPtr Function::removeQuadratic

(

)

Remove the quadratic part of the function and return a pointer to the quadratic part.

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

• /home/amahajan/tmp/minotaur-test/src/base/Function.h
• /home/amahajan/tmp/minotaur-test/src/base/Function.cpp