Hi! When compiling GiNaC with -DDO_GINAC_ASSERT, exam_clifford.cpp fails the test suite because clifford.cpp:105, assertion `is_a<varidx>(mu)' is violated. The function clifford_moebius_map constructs a clifford unit with an idx, not a varidx, if G is a matrix. The code in question was written by Vladimir in 2006. From a physicists point of view, I thought that it doesn't make sense to construct a clifford object with an idx instead of a varidx. But then, what's clifford_moebius_map doing? On the other hand, I also noticed that the tutorial does include examples of clifford objects with idx indices in section "A generic Clifford algebra". Strange. If someone with more insight could shed a light on this I could finish my recent quest to make GiNaC pass its test suite even when compiled with -DDO_GINAC_ASSERT. That would be great. Cheers -richy. -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>