HepTool::Evaluator Class Reference
[Evaluator]

Evaluator of arithmetic expressions with an extendable dictionary. More...

#include <Evaluator.h>

List of all members.

Public Types

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
}
 List of possible statuses. More...


Public Member Functions

 Evaluator ()
 Constructor.

 ~Evaluator ()
 Destructor.

double evaluate (const char *expression)
 Evaluates the arithmetic expression given as character string.

int status () const
 Returns status of the last operation with the evaluator.

int error_position () const
 Returns position in the input string where the problem occured.

void print_error () const
 Prints error message if status() is an ERROR.

void setVariable (const char *name, double value)
 Adds to the dictionary a variable with given value.

void setVariable (const char *name, const char *expression)
 Adds to the dictionary a variable with an arithmetic expression assigned to it.

void setFunction (const char *name, double(*fun)())
 Adds to the dictionary a function without parameters.

void setFunction (const char *name, double(*fun)(double))
 Adds to the dictionary a function with one parameter.

void setFunction (const char *name, double(*fun)(double, double))
 Adds to the dictionary a function with two parameters.

void setFunction (const char *name, double(*fun)(double, double, double))
 Adds to the dictionary a function with three parameters.

void setFunction (const char *name, double(*fun)(double, double, double, double))
 Adds to the dictionary a function with four parameters.

void setFunction (const char *name, double(*fun)(double, double, double, double, double))
 Adds to the dictionary a function with five parameters.

bool findVariable (const char *name) const
 Finds the variable in the dictionary.

bool findFunction (const char *name, int npar) const
 Finds the function in the dictionary.

void removeVariable (const char *name)
 Removes the variable from the dictionary.

void removeFunction (const char *name, int npar)
 Removes the function from the dictionary.

void clear ()
 Clear all settings.

void setStdMath ()
 Sets standard mathematical functions and constants.

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.


Detailed Description

Evaluator of arithmetic expressions with an extendable dictionary.

Example:

   #include "CLHEP/Evaluator/Evaluator.h"
   HepTool::Evaluator eval;
   eval.setStdMath();
   double res = eval.evaluate("sin(30*degree)");
   if (eval.status() != HepTool::Evaluator::OK) eval.print_error();

Author:
Evgeni Chernyaev <Evgueni.Tcherniaev@cern.ch>


Member Enumeration Documentation

anonymous enum
 

List of possible statuses.

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

See also:
status

error_position

print_error

Enumeration values:
OK  Everything OK.
WARNING_EXISTING_VARIABLE  Redefinition of existing variable.
WARNING_EXISTING_FUNCTION  Redefinition of existing function.
WARNING_BLANK_STRING  Empty input string.
ERROR_NOT_A_NAME  Not allowed sysmbol in the name of variable or function.
ERROR_SYNTAX_ERROR  Systax error.
ERROR_UNPAIRED_PARENTHESIS  Unpaired parenthesis.
ERROR_UNEXPECTED_SYMBOL  Unexpected sysbol.
ERROR_UNKNOWN_VARIABLE  Non-existing variable.
ERROR_UNKNOWN_FUNCTION  Non-existing function.
ERROR_EMPTY_PARAMETER  Function call has empty parameter.
ERROR_CALCULATION_ERROR  Error during calculation.


Member Function Documentation

double HepTool::Evaluator::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 (==, !=, >, >=, <, <=, &&, ||).

Parameters:
expression input expression.
Returns:
result of the evaluation.
See also:
status

error_position

print_error

bool HepTool::Evaluator::findFunction const char *  name,
int  npar
const
 

Finds the function in the dictionary.

Parameters:
name name of the function to be unset.
npar number of parameters of the function.
Returns:
true if such a function exists, false otherwise.

bool HepTool::Evaluator::findVariable const char *  name  )  const
 

Finds the variable in the dictionary.

Parameters:
name name of the variable.
Returns:
true if such a variable exists, false otherwise.

void HepTool::Evaluator::removeFunction const char *  name,
int  npar
 

Removes the function from the dictionary.

Parameters:
name name of the function to be unset.
npar number of parameters of the function.

void HepTool::Evaluator::removeVariable const char *  name  ) 
 

Removes the variable from the dictionary.

Parameters:
name name of the variable.

void HepTool::Evaluator::setFunction const char *  name,
double(*  fun)(double, double, double, double, double)
 

Adds to the dictionary a function with five parameters.

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

Parameters:
name function name.
fun pointer to the real function in the user code.

void HepTool::Evaluator::setFunction const char *  name,
double(*  fun)(double, double, double, double)
 

Adds to the dictionary a function with four parameters.

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

Parameters:
name function name.
fun pointer to the real function in the user code.

void HepTool::Evaluator::setFunction const char *  name,
double(*  fun)(double, double, double)
 

Adds to the dictionary a function with three parameters.

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

Parameters:
name function name.
fun pointer to the real function in the user code.

void HepTool::Evaluator::setFunction const char *  name,
double(*  fun)(double, double)
 

Adds to the dictionary a function with two parameters.

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

Parameters:
name function name.
fun pointer to the real function in the user code.

void HepTool::Evaluator::setFunction const char *  name,
double(*  fun)(double)
 

Adds to the dictionary a function with one parameter.

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

Parameters:
name function name.
fun pointer to the real function in the user code.

void HepTool::Evaluator::setFunction const char *  name,
double(*  fun)()
 

Adds to the dictionary a function without parameters.

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

Parameters:
name function name.
fun pointer to the real function in the user code.

void HepTool::Evaluator::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.)

void HepTool::Evaluator::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.

Parameters:
name name of the variable.
expression arithmetic expression.

void HepTool::Evaluator::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.

Parameters:
name name of the variable.
value value assigned to the variable.


The documentation for this class was generated from the following file:
Class Library for High Energy Physics (version 1.8)