i was using one global variable to achieve this.
i have modified core->operation-> AssocOp with the version 0.6.5
and sympify('1 + 1',evaluate=False)) was working exactly fine returning
"1+1"
but recently i have shifted to version 0.7.1
Issue is now when i call sympify("2*x+3*x) , this is not even going in to
AssocOp class __new_ method.
and somehow it returns 5*x
could you please tell which class does sympify uses to evaluate Add.
i am kind of stucked here.On Mon, Oct 3, 2011 at 9:13 PM, Aaron Meurer <[email protected]> wrote: > Currently there is not, but I don't think it would be very difficult > to add the behavior in as a global parameter at least. If you want to > just make it an option to sympify (like sympify('1 + 1', > evaluate=False)), I don't know how difficult that would be, since the > parser would have to be modified, but it should be doable. But we > definitely would accept a patch that does so. Please open an issue for > it in any case. > > As for multiplying by something causing an unevaluated expression to > evaluate, I consider this to be a bug. It no longer does it in master > with 1 (because the constructor ignores the identity), but it will > still do it with any other number. > > Aaron Meurer > > On Sun, Oct 2, 2011 at 10:44 PM, gsagrawal <[email protected]> wrote: > > yes , i am facing the same problems. > > specially when you try to convert a string format user input into a valid > > sympy expression using simpify(expr) which internally calls Add and Mul > with > > default parameter (evaluate=true). is there any way to control this ? > > On Mon, Oct 3, 2011 at 2:44 AM, Gabor Takacs <[email protected]> > wrote: > >> > >> Hi, > >> > >> I experienced that sympy applies automatic evaluation at expression > >> creation by default > >> (the evaluate parameter is True in the constructors). > >> > >> Therefore, e.g. > >> - I**3 evaluates to -I > >> - Pow(I, 3, evaluate=False) evaluates to I**3, but > >> Pow(I, 3, evaluate=False) * 1 evaluates to -I > >> > >> Is it possible to change the default behaviour to "no automatic > >> evaluation at expression creation"? > >> (so that I**3 evaluates to I**3) > >> > >> Gabor > >> > >> -- > >> 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. > > > > -- > 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.
