simon-git: spigot (master): Simon Tatham

[Commits to Tartarus CVS repository.]

TL;DR:
  52364e0 Use spigot_algebraic as a special case in pow().

Repository:     git://git.tartarus.org/simon/spigot.git
On the web:     http://tartarus.org/~simon-git/gitweb/?p=spigot.git
Branch updated: master
Committer:      Simon Tatham <anakin at pobox.com>
Date:           2014-12-27 11:51:48

commit 52364e08da65e517a2508d5ca9f80431b4c51ff7
web diff http://tartarus.org/~simon-git/gitweb/?p=spigot.git;a=commitdiff;h=52364e08da65e517a2508d5ca9f80431b4c51ff7;hp=8689b2bf89c6e02bff3db86da30bcbe37c034c76
Author: Simon Tatham <anakin at pobox.com>
Date:   Sat Dec 27 11:45:21 2014 +0000

    Use spigot_algebraic as a special case in pow().
    
    It's considerably faster to compute, say, 2^(7/12) by finding the
    positive root of x^12 = 2^7 than by the fully general exp/log system.
    We already had a special case for raising rationals to integer powers;
    now that's extended to cover raising rationals to _rational_ powers.
    
    I've limited the size of numerator and denominator in the power to
    something fairly arbitrary. One of these days I should probably go
    back and do the timing to decide what those figures _ought_ to be.

 exp.cpp |   39 +++++++++++++++++++++++++----------
 test.sh |   70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+), 11 deletions(-)