1Math::NumSeq::MephistoWUasletrz(C3o)ntributed Perl DocumMeanttha:t:iNounmSeq::MephistoWaltz(3)
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6 Math::NumSeq::MephistoWaltz -- Mephisto waltz sequence
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9 use Math::NumSeq::MephistoWaltz;
10 my $seq = Math::NumSeq::MephistoWaltz->new;
11 my ($i, $value) = $seq->next;
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14 The Mephisto waltz sequence, being the mod 2 count of ternary digit 2s
15 in i.
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17 0,0,1, 0,0,1, 1,1,0, ...
18 starting i=0
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20 i=0 has no 2s so value=0, and likewise i=1 value=0. Then i=2 has one 2
21 so value=1.
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23 The sequence can also be expressed as starting with 0 and repeatedly
24 expanding
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26 0 -> 0,0,1
27 1 -> 1,1,0
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29 So
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31 0
32 0,0,1
33 0,0,1, 0,0,1, 1,1,0,
34 0,0,1, 0,0,1, 1,1,0, 0,0,1, 0,0,1, 1,1,0, 1,1,0, 1,1,0, 0,0,1
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36 | original | | copy | | inverse |
37 +-----------------+ +-----------------+ +-----------------+
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39 The effect of the expansion is keep the first third the same, append a
40 copy of it, and append an inverse of it 0<->1.
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43 See "FUNCTIONS" in Math::NumSeq for behaviour common to all sequence
44 classes.
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46 "$seq = Math::NumSeq::MephistoWaltz->new ()"
47 Create and return a new sequence object.
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49 Random Access
50 "$value = $seq->ith($i)"
51 Return the $i'th MephistoWaltz value, being the count mod 2 of the
52 ternary digit 2s in $i.
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54 "$bool = $seq->pred($value)"
55 Return true if $value occurs in the sequence, which simply means 0
56 or 1.
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59 The calculation can be made in a power-of-3 base like 9, 27, 81, etc
60 instead of just 3. For example in base 9 digits 2, 5, 6, 7 have a one
61 (mod 2) ternary 2. These base 9 digits correspond to the 1s in the
62 initial sequence 0,0,1, 0,0,1, 1,1,0 shown above.
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65 Math::NumSeq, Math::NumSeq::DigitSumModulo
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68 <http://user42.tuxfamily.org/math-numseq/index.html>
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71 Copyright 2011, 2012, 2013, 2014, 2016 Kevin Ryde
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73 Math-NumSeq is free software; you can redistribute it and/or modify it
74 under the terms of the GNU General Public License as published by the
75 Free Software Foundation; either version 3, or (at your option) any
76 later version.
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78 Math-NumSeq is distributed in the hope that it will be useful, but
79 WITHOUT ANY WARRANTY; without even the implied warranty of
80 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
81 General Public License for more details.
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83 You should have received a copy of the GNU General Public License along
84 with Math-NumSeq. If not, see <http://www.gnu.org/licenses/>.
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88perl v5.30.0 2019-08-05 Math::NumSeq::MephistoWaltz(3)