Hi all, Has anyone tried to add *units-of-measurement checking* to GiNaC? I have some nice unit-checking code here as part of the freesteam project, http://pye.dyndns.org/freesteam/docs/class_units.html This class prevents things like "1 * bar + 3 * kg", and also ensures validity of things like "Density rho = 5 * kg / (2 * metre2)" This units class could conceivably be extended to pass through expressions rather than simple numerical results, but operations like differentiation might need to become units-savvy I suspect. Does anyone have any comments on the advisability / feasibility of trying to do this, or have any references I should follow up relating to other people attempting this? Cheers JP -- John Pye School of Mechanical and Manufacturing Engineering The University of New South Wales Sydney NSW 2052 Australia t +61 2 9385 5127 f +61 2 9663 1222 mailto:john.pye_AT_student_DOT_unsw.edu.au http://pye.dyndns.org/