HepTool::Evaluator

HepTool::Evaluator is an evaluator of arithmetic expressions with an extendable dictionary.

Author

Declaration

#include "CLHEP/Evaluator/Evaluator.h"

namespace HepTool
class Evaluator

Public Member Functions

Constructor

Evaluator()

Copy constructor

Copy constructor is disabled.

Destructor

~Evaluator()

=

Assignment is disabled.

clear

void clear()

Clear all settings.

error_position

int error_position() const

Returns position in the input string where the problem occured.

evaluate

double evaluate(const char * expression)

Evaluates the arithmetic expression given as character string. The expression may consist of numbers, variables and functions separated by arithmetic (+, - , /, *, ^, **) and logical operators (==, !=, > >=, <, <=, &&, ||).

findFunction

HepBoolean findFunction(const char * name, int npar) const

Finds the function in the dictionary.

findVariable

HepBoolean findVariable(const char * name) const

Finds the variable in the dictionary.

print_error

void print_error() const

Prints error message if status() is an ERROR.

setFunction

void setFunction(const char * name, double (*fun)())

Adds to the dictionary the function without parameters.

If such a function already exist in the dictionary, then status will be set to WARNING_EXISTING_FUNCTION.

void setFunction(const char * name, double (*fun)(double))

Adds to the dictionary the function with one parameter.

If such a function already exist in the dictionary, then status will be set to WARNING_EXISTING_FUNCTION.

void setFunction(const char * name, double (*fun)(double,double))

Adds to the dictionary the function with two parameters.

If such a function already exist in the dictionary, then status will be set to WARNING_EXISTING_FUNCTION.

void setFunction(const char * name, double (*fun)(double,double,double))

Adds to the dictionary the function with three parameters.

If such a function already exist in the dictionary, then status will be set to WARNING_EXISTING_FUNCTION.

void setFunction(const char * name, double (*fun)(double,double,double,double))

Adds to the dictionary the function with four parameters.

If such a function already exist in the dictionary, then status will be set to WARNING_EXISTING_FUNCTION.

void setFunction(const char * name, double (*fun)(double,double,double,double,double))

Adds to the dictionary the function with five parameters.

If such a function already exist in the dictionary, then status will be set to WARNING_EXISTING_FUNCTION.

setStdMath

void setStdMath()

Sets standard mathematical functions and constants.

setSystemOfUnits

void setSystemOfUnits

(

double meter = 1.0,
double kilogram = 1.0,
double second = 1.0,
double ampere = 1.0,
double kelvin = 1.0,
double mole = 1.0,
double candela = 1.0

)

Sets system of units. Default is the SI system of units.

To set the CGS (Centimeter-Gram-Second) system of units one should call:

setSystemOfUnits(100., 1000., 1.0, 1.0, 1.0, 1.0, 1.0);

To set system of units accepted in the GEANT4 simulation toolkit one should call:

setSystemOfUnits(1.e+3, 1./1.60217733e-25, 1.e+9, 1./1.60217733e-10,1.0, 1.0, 1.0);

The basic units in GEANT4 are:

millimeter (millimeter = 1.)
nanosecond (nanosecond = 1.)
Mega electron Volt (MeV = 1.)
positron charge (eplus = 1.)
degree Kelvin (kelvin = 1.)
the amount of substance (mole = 1.)
luminous intensity (candela = 1.)
radian (radian = 1.)
steradian (steradian = 1.)

setVariable

void setVariable(const char * name, double value)

Adds to the dictionary a variable with given value.

If a variable with such a name already exist in the dictionary, then status will be set to WARNING_EXISTING_VARIABLE.

void setVariable(const char * name, const char * expression)

Adds to the dictionary a variable with an arithmetic expression assigned to it.

If a variable with such a name already exist in the dictionary, then status will be set to WARNING_EXISTING_VARIABLE.

status

int status() const

Returns status of the last operation with the evaluator. In case if status() is an ERROR the corresponding error message can be printed with print_error().

List of possible statuses:

enum

{

OK,

WARNING_EXISTING_VARIABLE,

WARNING_EXISTING_FUNCTION,

WARNING_BLANK_STRING,

ERROR_NOT_A_NAME,

ERROR_SYNTAX_ERROR,

ERROR_UNPAIRED_PARENTHESIS,

ERROR_UNEXPECTED_SYMBOL,

ERROR_UNKNOWN_VARIABLE,

ERROR_UNKNOWN_FUNCTION,

ERROR_EMPTY_PARAMETER,

ERROR_CALCULATION_ERROR

}

removeVariable

void removeVariable(const char * name)

Removes the variable from the dictionary.

removeFunction

void removeFunction(const char * name, int npar)

Removes the function from the dictionary.

Example