So the difference is that it numbers the symbol for you, i.e., you pass a Symbol instead of a name?
I think if you think it would be useful, we should just put constantsimp in the main namespace, and perhaps choose the best API with regards to this. Aaron Meurer On Mon, Sep 12, 2011 at 2:51 PM, Chris Smith <[email protected]> wrote: > `def constantsimp(expr, independentsymbol, endnumber, startnumber=1, > symbolname='C'):` It is looking to absorb constants into the the > numbered symbols. proportional_form combines everything except x. I > suppose one could use a renumbering scheme to assign a numbered symbol > to all non-x symbols and then run it through constantsimp. hmmm - that > didn't occur to me earlier (more below). > > ```python >>>> constantsimp(x+C0+y,x,1) # I think this is a bug > C0 + x + y > ``` > > ```python >>>> proportional_form(x+C0+y,x) > C0 + x > ``` > > For comparison purposes, I am defining a function that will call > constantsimp after replacing all non-x symbols with numbered symbols: > > ```python >>>> def proportional_form(eq,x,s=Symbol('C')): > ... eq=eq.subs([(sy, Symbol(s.name+str(i))) for i,sy in > enumerate(eq.atoms(Symbol)) if sy!=x]) > ... return constantsimp(eq,x,5,symbolname=s.name) > ... >>>> proportional_form(y + z, x) > C1 >>>> proportional_form(Integral(x, (x, 1, 2)), x, C) > Integral(x, (x, 1, 2)) >>>> # should have been C0 <==================== difference > ... >>>> proportional_form(x**2*y*exp(x+z) + x*y + x*z, x, C) > C1*x + C2*x**2*exp(x) >>>> proportional_form(x**2*y*exp(x+z) + x*y + x*z, x, k) > k1*x + k2*x**2*exp(x) >>>> proportional_form(3 + y*x + x*z, x, C) > C1*x + 3 >>>> # or 3->C0 <==============================trivial difference > ... >>>> proportional_form(3 + y*x + x*z + x**2*z, x, C) > C1*x + C2*x**2 + 3 >>>> proportional_form(x - y, x, C) > C1 + x >>>> proportional_form(-x + y, x, C) > C1 - x >>>> proportional_form(-2*x + y, x, C) > C1 - 2*x >>>> # or 2-> C0 <======================= ditto > ``` > > Perhaps instead of adding another routine, a wrapper that does the > symbol replacement could be made and the few remaining bugs in > constantsimp sorted out. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
