computing the degree of polynomails

[Rishabh Kumar]

hello,

myself Rishabh , i am currently pursuing my M.Sc in applied mathematics from IIT roorkee. i have been following the discussions on mailing list for quite some time. I would like to contribute to the open source software and become a part of Gsoc 2014 as i found sympy module very interesting and effective.

To start with, I have cloned your git repository and have started inspecting the code. while using sympy i found that sympy is not able to compute the degree of polynomials and expressions such as (x+y+z)**10000 in real time and the process has to be terminated. I wish to suggest a new way to compute the degree of the polynomials using recurrences . Should I start preparing a pull request or submit a patch ?

hoping for an early response and your faithful guidance .....

-Rishabh kumar 

[Sergey Kirpichev]

On Saturday, February 15, 2014 2:58:07 PM UTC+4, Rishabh Kumar wrote:

while using sympy i found that sympy is not able to compute the degree of polynomials and expressions such as (x+y+z)**10000 in real time and the process has to be terminated. I wish to suggest a new way to compute the degree of the polynomials using recurrences . Should I start preparing a pull request or submit a patch ?

Yes, please try to do.  Please also search our bugtracker, as there is something about this problem (and several attempts to solve it, AFAIK).

[Harsh Gupta]

See, https://code.google.com/p/sympy/issues/detail?id=3223.

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Harsh

[Rishabh Kumar]

there are 2 functions to compute the degree of the polynomials : degree() and total_degree(). 

when we use them:

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>>> poly(x**3+y**5+z).degree()              #wrong

3

>>> poly(x**3+y**5+z).total_degree()          #correct

5

>>>poly(y**6*x**3+y**5+z).degree()       #wrong

3

>>> poly(y**6*x**3+y**5+z).total_degree()      #correct

9

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mentors please clarify their significance. I am finding it a bit ambiguous.

[Aaron Meurer]

There is also a bug for this somewhere too, I think. The reason is
that degree takes the degree in the first variable, which, since you
didn't specify the variables, is chosen automatically to be x.

Aaron Meurer

[Rishabh Kumar]

while working on the patch , i came across the works of Monagen , Pearce and van hoeji and their work with polynomials. i believe that would be better if we work on that . It may revamp the polys module.