math_GaussSingleIntegration _int
( *static_cast<math_Function*>( const_cast<FunctionExpr*> (this) ), a, b, 20 );
if( _int.IsDone() )
math_GaussSingleIntegration _int
( *static_cast<math_Function*>( const_cast<FunctionExpr*> (this) ), a, b, 20 );
if( _int.IsDone() )