22.03.2012 09:33, Sai Nikhil пишет: > currently if we are calculating the series for a function ( eg., > sin(x).series(x,x0=2,n=6) ) about a point "x0 = a" , where "a != 0" , > > then we are getting the expression of f(x+a) (i.e., > sin(x+2).series(x,x0=0,n=6)) about "x0 = 0" , as there is no proper support > for Order term Arithmetic in sympy . >
1. Frankly speaking, this is not the whole truth. Yes, there is a problem in the representing of asymptotic series near non-zero point, as there is no proper support for Order arithmetic, but the Order arithmetic depends on the rest expression. Order term must know (and therefore parse) many things of the rest expression, and it is not known what arithmetic is easer. 2. You can see where Order is used now, in simple x==0 case, by searchiong source lines for the "is_Order" string. In the main, the code in those lines tests this property of symbolic expression and deside how to handle with it further. In many places. The Order expression itself, as described as class and aimed to maintain common cases (as docstring says) , is placed in the "sympy/series/order.py" file. See also "sympy/series/tests/test_order.py" for examples. 3. Another difficulty, that now in SymPy (somehow) not only the power series are implement, but generalized, e.g. 1 + (log(x)*x) + (log(x)*x)**2 + ... 4. We have the two ways: * represent assymptotic series as unstructured expression, as it presents now in SymPy. In this case we must implement Order term extensively. But it is not qiet efficient, or even known how to deal with it in common cases. * represent assymptotic series as expression which has the structure, like polynomes keep coefficients only. So, as conclusion, I afraid to say that it is not easy issue. Alexey. > I want to improve the Order term Arithmetic (around a point that is not '0') > ... > > can you please give me the references for completing this ... > > > *-thanks,* > *Sai Nikhil .T <http://www.tsndiffopera.in>* > > * > * > *1* > -- 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.
