// as described in Hasegawa, Genetic Programming - New Approaches and Successful Applications
PROBLEM DMAX
CODE <<
>>

INIT <<
>>

NONTERMINALS
  Expr<<out double v>>.
  Add3<<out double v>>.
  Mul3<<out double v>>.

TERMINALS
  X1. X2.

RULES
  Expr<<out double v>> =
    Mul3<<out v>>
    | Add3<<out v>>
    | X1                                                   SEM << v = 0.95; >>
    | X2                                                   SEM << v = -1; >>
  .

  Mul3<<out double v>> =                                   LOCAL << double v1, v2, v3; >>
     Expr<<out v1>> Expr<<out v2>> Expr<<out v3>>          SEM << v = v1 * v2 * v3; >>
  .

  Add3<<out double v>> =                                   LOCAL << double v1, v2, v3; >>
     Expr<<out v1>> Expr<<out v2>> Expr<<out v3>>          SEM << v = v1 + v2 + v3; >>
  .
  
MAXIMIZE
  << 
    double v;
    Expr(out v);
    return v;
  >>
END SymbRegKoza.