gridripper::math::expr::Expr Class Reference

Evaluates mathematical expressions or functions. More...

#include <Expr.h>

Inheritance diagram for gridripper::math::expr::Expr:

List of all members.

Public Member Functions
	Expr (const string &s) throw (Error&)
	Construct a mathematical expression containing numbers only.
	Expr (const string &s, const tvector< StkOp * > &funcs, StkOpRepository *funcRep=NULL) throw (Error&)
	Construct a function from the specified string and variables.
const string &	getString () const
	Gets the expression as a string.
string	getProgramListString () const
	Gets the "program" as a printable string.
GReal_t	eval ()
	Evaluate the expression.
bool	isConstant () const
	Returns true if the expression is determined to be a constant.
bool	dependsOn (const StkOp &f) const
	Returns true if the expression contains the specified function.
bool	dependsOnVariables () const
	Returns true if the expression uses external variables.
void	replaceVar (const string &name, StkVar &var)
	Replaces all occurances of a variable with another one in the program.
void	evalStack (GReal_t *&stack) const
	Evaluates the stack.
StkOp **	getInternalProgram () const
	Gets the "program".
virtual string	getClassName () const
	Gets the class name.
Static Public Member Functions
static string::size_type	findExprEnd (const string &str, string::size_type i)
	Finds end of "x?y:z" after the colon.
Classes
class	Error
	Exception thrown by the Expr constructor in case of syntax error. More...

---

Detailed Description

Evaluates mathematical expressions or functions.

Example:

f(x) = x^0.5*atan(1)/sqrt(pi)

    StkVar vX("x");           // define variable
    StkConst xPi("pi", M_PI); // define a constant
    tvector<StkOp*> funcs;
    funcs.push_back(&vX);
    funcs.push_back(&xPi);
    try {
        Expr expr("x^0.5*atan(1)/sqrt(pi)", funcs); // create Expr
        vX.value = 5; // set value of variable
        cout << "f(5) = " << expr.eval() << endl;  // calculate f(5)
    } catch(Expr::Error& ex) {
        cerr << ex.what() << endl;
    }
 

Version:

GridRipper 0.5, 11/16/2008

Since:

GROMIT 0.2 (2001)

Author:

Peter Csizmadia

---

Constructor & Destructor Documentation

gridripper::math::expr::Expr::Expr

(

const string &

s

)

throw (Error&)

Construct a mathematical expression containing numbers only.

Parameters:

s

the expression

gridripper::math::expr::Expr::Expr	(	const string &	s,
		const tvector< StkOp * > &	funcs,
		StkOpRepository *	funcRep = NULL
	)			throw (Error&)

Construct a function from the specified string and variables.

Parameters:

	s	the expression
	funcs	extra functions and variables
	funcRep	function repository

---

Member Function Documentation

const string& gridripper::math::expr::Expr::getString

(

)

const [inline]

Gets the expression as a string.

Returns:

the expression

string gridripper::math::expr::Expr::getProgramListString

(

)

const

Gets the "program" as a printable string.

Useful for debugging.

Returns:

the program list

GReal_t gridripper::math::expr::Expr::eval

(

)

Evaluate the expression.

bool gridripper::math::expr::Expr::dependsOn

(

const StkOp &

f

)

const [virtual]

Returns true if the expression contains the specified function.

Subexpressions are also checked, recursively.

Reimplemented from gridripper::math::expr::StkFunc.

bool gridripper::math::expr::Expr::dependsOnVariables

(

)

const

Returns true if the expression uses external variables.

void gridripper::math::expr::Expr::replaceVar	(	const string &	name,
		StkVar &	var
	)

Replaces all occurances of a variable with another one in the program.

Parameters:

	name	the variable name
	var	the new variable

void gridripper::math::expr::Expr::evalStack

(

GReal_t *&

stack

)

const [virtual]

Evaluates the stack.

Parameters:

stack

the stack pointer

Implements gridripper::math::expr::StkFunc.

StkOp** gridripper::math::expr::Expr::getInternalProgram

(

)

const [inline]

Gets the "program".

Returns:

the array of stack operations

virtual string gridripper::math::expr::Expr::getClassName

(

)

const [inline, virtual]

Gets the class name.

Returns:

the class name

Reimplemented from gridripper::math::expr::StkFunc.

---

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

• gridripper/math/expr/Expr.h