Suresh,
On Tue, Dec 11, 2007 at 09:47:58AM -0800, Suresh Jeevanandam wrote:
>
> Dear all,
>
> Let's say I have an expression:
> 1/(a+b)
>
> I want to be able to simplify this to 1/a if we know that a is much,
> much greater than b. Is there a way to achieve this already in sympy.
> If not, I think this would be a nice feature for engineering people
> who would always be making some approximations and get intuitions from
> the simplified expressions :)
An example related to your question:
In [2]: e = 1/(x+y)
In [3]: e
Out[3]:
1
-----
x + y
In [4]: e.series(y, 1)
Out[4]:
1
- + O(y)
x
You can do it more carefully:
if y << x <==> t = y/x << 1, so
In [5]: t = Symbol('t')
In [6]: et = e.subs(y, t*x)
In [7]: et
Out[7]:
1
-------
x + t*x
In [8]: ets = et.series(t, 1)
In [9]: ets
Out[9]:
1
- + O(t)
x
In [10]: ets.subs(t, y/x)
Out[10]:
1
- + O(y/x, x, y)
x
Is that what you need?
--
Всего хорошего, Кирилл.
http://landau.phys.spbu.ru/~kirr/aiv/
--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---
