[PPL-devel] GenSys.cc: lines 247 and following

[Roberto Bagnara]

Enea Zaffanella wrote:
> 	Patched the method insert(const Generator&), which was doing nasty things
> 	when trying to insert a generator into an empty generator system that
> 	was declared to be NNC.

These lines now read as follows:

       // The generator system is NOT necessarily closed:
       // copy the generator, adding the missing dimensions
       // and the epsilon coefficient.
       // NOTE: computing `gs_size = num_columns()' would provide
       //       a wrong result if the matrix has no rows.
       size_t new_size = (g.space_dimension() > space_dimension())
			 ? g.space_dimension() + 2
			 : space_dimension() + 2;
       Generator tmp_g(g, new_size);
       // If it was a point, set the epsilon coordinate to 1
       // (i.e., set the coefficient equal to the divisor).
       // Note: normalization is preserved.
       if (tmp_g[0] != 0)
	tmp_g[new_size - 1] = tmp_g[0];
       tmp_g.set_not_necessarily_closed();
       // Inserting the new generator.
       Matrix::insert(tmp_g);

There is an inconsistent comment about a variable no longer
being used (`gs_size') and a possibly repeated evaluation
of g.space_dimension().  I suggest replacing the three lines
above with something like

       size_t new_size = 2 + std::max(g.space_dimension(), space_dimension());

-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it