#include <DGtal/io/readers/MPolynomialReader.h>

Inheritance diagram for DGtal::MPolynomialGrammar< Iterator >:

Public Member Functions
	MPolynomialGrammar ()

Data Fields
qi::rule< Iterator, detail::top_node(), ascii::space_type >	top
qi::rule< Iterator, detail::top_node(), ascii::space_type >	mulexpr
qi::rule< Iterator, detail::expr_node(), ascii::space_type >	subexpr
qi::rule< Iterator, detail::top_node(), ascii::space_type >	expexpr
qi::rule< Iterator, detail::monomial_node(), ascii::space_type >	monomial
qi::rule< Iterator, detail::power_node(), ascii::space_type >	variable
qi::rule< Iterator, detail::power_node(), ascii::space_type >	genvariable
qi::rule< Iterator, detail::power_node(), ascii::space_type >	litvariable

Detailed Description

template<typename Iterator>
struct DGtal::MPolynomialGrammar< Iterator >

Defines a grammar for parsing multi-variate polynomials. Based on boost::spirit. You should use a MPolynomialReader to make polynomials from input strings. Another way is to use the overloaded DGtal::operator>>(std::istream &,MPolynomial<n,TRing,TAlloc> &).

Definition at line 148 of file MPolynomialReader.h.

Constructor & Destructor Documentation

◆ MPolynomialGrammar()

template<typename Iterator>

DGtal::MPolynomialGrammar< Iterator >::MPolynomialGrammar ( )

inline

Definition at line 151 of file MPolynomialReader.h.

      : MPolynomialGrammar::base_type(top)
    {
      using qi::eps;
      using qi::lit;
      using qi::int_;
      using qi::_val;
      using qi::_1;
      using qi::double_;
      using phoenix::at_c;
      using phoenix::push_back;
 
      top = // An expression is an additive or subtractive expression
        mulexpr [push_back(at_c<1>(_val), _1)] 
        >> *( ( lit('+') [ push_back(at_c<0>(_val), '+') ] 
                >> mulexpr [push_back(at_c<1>(_val), _1)]  )
              | ( ( lit('-') [ push_back(at_c<0>(_val), '-') ] 
                    >> mulexpr [push_back(at_c<1>(_val), _1)]  ) ) );
      
      mulexpr = // Each mul expression may be a product of sub-expressions
        subexpr [push_back(at_c<1>(_val), _1)] 
        >> *( ( lit('*') [ push_back(at_c<0>(_val), '*') ]
                >> mulexpr [push_back(at_c<1>(_val), _1)] ) );
 
      subexpr =  // a sub-expression is a monomial or some ( ) or some ( )^k
        monomial 
        | expexpr;
 
      expexpr = // ( expr ) or ( expr )^k
        lit('(') [ push_back(at_c<0>(_val), '^') ] 
        >> top [ push_back(at_c<1>(_val), _1) ]
        >> lit(')') 
        >> ( ( lit('^') >> int_ [ at_c<2>(_val) = _1 ] )
             | eps [ at_c<2>(_val) = 1 ]  ) ;
        
      monomial =   // coef.power(s)*, or power(s)+
        ( double_ [at_c<0>(_val) = _1] 
          >> *( genvariable [push_back(at_c<1>(_val), _1)] ) )
        | +( genvariable [push_back(at_c<1>(_val), _1)] 
             >> eps [at_c<0>(_val) = 1] );
 
      genvariable = // may be some X_k^m or x^m, y^m ...
        litvariable | variable;
      variable = // X_0 X_1 ... X_0^4 X_1^2 X_3^0 ...
        lit('X') >> lit('_') 
                 >> int_ [at_c<0>(_val) = _1]
                 >> ( ( lit('^') >> int_ [at_c<1>(_val) = _1] ) // X_k^e
                      | eps [at_c<1>(_val) = 1] // X_k
                      );
      litvariable = // x y z t x^4 y^5 z^2 ...
        ( lit('x') [at_c<0>(_val) = 0]
          | lit('y') [at_c<0>(_val) = 1] 
          | lit('z') [at_c<0>(_val) = 2] 
          | lit('t') [at_c<0>(_val) = 3] )
        >> ( ( lit('^') >> int_ [at_c<1>(_val) = _1] ) // x^3 z^4
             | eps [at_c<1>(_val) = 1] // x y z
             );
 
    }