Method prod

inst/include/Rcpp/Dimension.h:59–61

	        return (int) dims.size() ;
	    }
	    inline R_xlen_t prod() const {
	        return std::accumulate( dims.begin(), dims.end(), static_cast<R_xlen_t>(1), std::multiplies<R_xlen_t>() );
	    }

	    inline reference operator[](int i){
	        if( i < 0 || i>=static_cast<int>(dims.size()) ) throw std::range_error("index out of bounds") ;