Math::NumSeq::JugglerSteps -- steps in the juggler sqrt sequence
use Math::NumSeq::JugglerSteps; my $seq = Math::NumSeq::JugglerSteps->new; my ($i, $value) = $seq->next;
This is the number of steps it takes to reach 1 by the Juggler sqrt sequence,
n -> / floor(n^(1/2)) if n even \ floor(n^(3/2)) if n odd
So it's a sqrt if n even, or sqrt(n^3) if odd, rounding downwards each time. For example i=17 goes 17 -> sqrt(17^3)=70 -> sqrt(70)=8 -> sqrt(8)=2 -> sqrt(2)=1, for a count of 4 steps.
The intermediate values in the calculation can become quite large.
Math::BigInt is used if necessary. There's some secret experimental caching in a temp file, for a small speedup.
See "FUNCTIONS" in Math::NumSeq for the behaviour common to all path classes.
$seq = Math::NumSeq::JugglerSteps->new ()
$seq = Math::NumSeq::JugglerSteps->new (step_type => 'both', juggler_type => '1/2-3/2')
Create and return a new sequence object.
step_typeparameter (a string) selects between
"up" upward steps sqrt(n^3) "down" downward steps sqrt(n) "both" both up and down, which is the default
juggler_typeparameter (a string) selects among variations on the powering
n even n odd "1/2-3/2" sqrt(n) and sqrt(n^3) "2/3-3/2" cbrt(n^2) and sqrt(n^3) "3/4-4/3" n^(3/4) and n^(4/3)
$value = $seq->ith($i)
Return the number of steps to take
$idown to 1.
$bool = $seq->pred($value)
Return true if
$valueoccurs as a step count. This is simply
$value >= 0.
Copyright 2010, 2011 Kevin Ryde
Math-NumSeq is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.
Math-NumSeq is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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