On Aug 19, 2009, at 1:59 PM, William Stein wrote:
> > > MATHEMATICA: > In[1]:= u := 1 + k; u > Out[1]= 1 + k > In[2]:= k := 1; > In[3]:= u > Out[3]= 2 > > MAPLE: >> u := 1+k; > u := 1 + k >> u; > 1 + k >> k := 1; > k := 1 >> u; > 2 > > Wow, that's pretty interesting. So Maple and Mathematica also have > the (bizarre) semantics the user wants, but no other language I > tested does, including Maxima. > > This would thus be a very useful thing to add to the Sage tutorial, as > users coming over from Maple and Mathematica *should* expect this > weird semantic, since it is what they learned and are used to. We > should have exactly this example to illustrate this subtle point. > > <flamebait> The computer scientist in me just can't believe Maple and > Mathematica are designed that way. It's just sad. </flamebait> Note that it depends upon how you define u in Maple, if you instead define u as u = 1 + k you'll get the same result as the others. So, you can have either result. In one, you've defined an expression where u is the reference to it, and the other is an equation. In Maple, if you update a variable in an expression, it will be changed in all expressions that use that variable (once they're evaluated). However, it won't change references to the variable in equations. Cheers, Tim. --- Tim Lahey PhD Candidate, Systems Design Engineering University of Waterloo http://www.linkedin.com/in/timlahey --~--~---------~--~----~------------~-------~--~----~ To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
