#10532: Faster multiplication for multivariate power series
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Reporter: niles | Owner: malb
Type: enhancement | Status: needs_info
Priority: major | Milestone:
Component: commutative algebra | Keywords: multivariate power series
multiplication Karatsuba
Author: pernici | Upstream: N/A
Reviewer: Niles Johnson | Merged:
Work_issues: |
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Comment(by pernici):
In the message above I claimed that patch (1) uses do_mul_trunc_generic;
this is not true for RR, in which case it falls back to _mul_generic,
the classical multiplication;
this is the reason for which (1) is much slower than the K=infinity
case for RR, calling do_trunc_classical.
Since the truncated classical multiplication
do_trunc_classical computes
the same terms as the classical multiplication, apart from those
which are then truncated away, it is fine for non-exact fields.
The conclusion of the previous message stands:
I think that (2) with K=infinity (or a large integer to avoid
using infinity) is the best choice.
lftabera wrote:
>If K=infinity is needed to obtain good performance then either we are
doing something wrong or truncated karatsuba should be eliminated in favor
of the classical truncated algorithm.
Right, it can call directly the classical truncated algorithm, but the
K=infinity case
calls the classical truncated algorithm almost immediately, so
I think that the overhead of calling it is negligible anyway.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10532#comment:5>
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