Hello,
On Mon, 29 Jun 2009 09:41:14 -0700 (PDT), ahabrard <amaury.habrard@lif.univ-mrs.fr> said: A> const unsigned tinfo=2; symbol x("x", A> return_types::noncommutative,&tinfo)
Which version of GiNaC you are using, 1.4 branch I suppose? This code is not working with the current 1.5 branch. Moreover I could not figure out how to make non-commutative symbols at the moment, probably a patch is required for this. What other developers think, shall we simply add a new class ncsymbol derived from symbol? A> Ginac stops with the following message: "Terminate called after A> throwing an instance of 'std::logic_error' A> what(): add::eval(): sum of non-commutative objects has A> non-zero numeric A> term Abort trap" GiNaC seems to forbid to make matrices out of non-commutative object in order to avoid complications with nested non-commutativities. If you know that you want you may need to derive a new class from matrices to handle it. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv@maths.leeds.ac.uk -- www: http://maths.leeds.ac.uk/~kisilv/