Gerhard Niklasch on Tue, 3 Jul 2001 11:05:17 +0200 (MEST) |
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Re: Polynomial/Series Precision |
In response to: > Message-ID: <Pine.LNX.4.33.0107030248160.11392-100000@math.Princeton.EDU> > Date: Tue, 3 Jul 2001 02:59:54 -0400 (EDT) > From: "Jonathan P. Hanke" <jonhanke@Math.Princeton.EDU> > > It's very possible that this is a silly question, but I was having some > trouble working with large exponents in polynomials. In particular, I > would like to work with powers larger than x^65532, but when I try I > recieve a "*** degree overflow" error. With a 32-bit gp executable, we only have 16 bits to represent an exponent - or more precisely, since the representation doesn't take sparseness into account, we only have 16 bits to represent the length of the vector of coefficients (including a few words for internal administrative business). Thus x^(2^16) cannot be represented in the internal format, giving rise to the degree overflow message. A 64-bit executable (on platforms which support this) will get around this limitation, but will still consume enormous amounts of memory when handling polynomials of this size (and spend rather a lot of time in doing so). > I have tried changing the seriesprecision with \ps and default, but it > doesn't help the error. (Polynomials aren't series -- the seriesprecision determines at which term a power series will be truncated by default. This applies e.g. when you enter cos(x) and look at the resulting series output.) Hope this helps, Gerhard