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Topic: PolynomialQuotient slow
Replies: 3   Last Post: Jan 7, 2013 12:35 AM

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 Roman Pearce Posts: 121 Registered: 1/25/05
PolynomialQuotient slow
Posted: Dec 31, 2012 7:45 PM

Something seems wrong here with the performance of PolynomialQuotient. Is there blowup because the leading coefficient in x is a polynomial? Also it seems slower in Mathematica 9 versus v8.

d = 5
f = Expand[ ((1+x)*(1+y)*(1+z))^d + 1 ];
g = Expand[ ((1-x)*(1-y)*(1-z))^d + 1 ];
AbsoluteTiming[ p = Expand[ f g ]; ]
AbsoluteTiming[ q = PolynomialQuotient[p, f, x]; ]
AbsoluteTiming[ P = Factor[ p ]; ]

What is the preferred method for (exact) division of polynomials? On this example I tried Cancel[ p/f ] and it works fine, but on other problems it is faster to use PolynomialQuotient. Suggestions?

Date Subject Author
12/31/12 Roman Pearce
1/2/13 Daniel Lichtblau
1/5/13 Roman Pearce
1/7/13 Daniel Lichtblau