Math::PlanePath::Base::Digits(3pm)

1Math::PlanePath::Base::UDsiegritCso(n3t)ributed Perl DocMuamtehn:t:aPtliaonnePath::Base::Digits(3)
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NAME

6       Math::PlanePath::Base::Digits -- helpers for digit based paths
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SYNOPSIS

9        use Math::PlanePath::Base::Digits 'digit_split_lowtohigh';
10        foreach my $digit (digit_split_lowtohigh ($n, 16)) {
11        }
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DESCRIPTION

14       This is a few generic helper functions for paths based on digits or
15       powering.
16
17       They're designed to work on plain Perl integers and floats and there's
18       some special case support for "Math::BigInt".
19

EXPORTS

21       Nothing is exported by default but each function below can be as in the
22       usual Exporter style,
23
24           use Math::PlanePath::Base::Digits 'round_down_pow';
25
26       (But not "parameter_info_radix2()", for the reason described below.)
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FUNCTIONS

29   Generic
30       "($power, $exponent) = round_up_pow ($n, $radix)"
31       "($power, $exponent) = round_down_pow ($n, $radix)"
32           Return the power of $radix equal to or either higher or lower than
33           $n.  For example
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35              ($pow, $exp) = round_down_pow (260, 2);
36              # $pow==512  # the next higher power
37              # $exp==9    # the exponent in that power
38              # 2**9=512 is next above 260
39
40              ($pow, $exp) = round_down_pow (260, 2);
41              # $pow==256  # the next lower power
42              # $exp==8    # the exponent in that power
43              # 2**8=256 is next below 260
44
45       "@digits = digit_split_lowtohigh ($n, $radix)"
46       "@bits = bit_split_lowtohigh ($n)"
47           Return a list of digits from $n in base $radix, or in binary.  For
48           example,
49
50              @digits = digit_split_lowtohigh (12345, 10);
51              # @digits = (5,4,3,2,1)   # decimal digits low to high
52
53           If "$n==0" then the return is an empty list.  The current code
54           expects "$n >= 0".
55
56           "lowtohigh" in the name tries to make it clear which way the digits
57           are returned.  "reverse()" can be used to get high to low instead
58           (see "reverse" in perlfunc).
59
60           "bit_split_lowtohigh()" is the same as "digit_split_lowtohigh()"
61           called with radix=2.
62
63       "$n = digit_join_lowtohigh ($arrayref, $radix)"
64       "$n = digit_join_lowtohigh ($arrayref, $radix, $zero)"
65           Return a value made by joining digits from $arrayref in base
66           $radix.  For example,
67
68              @digits = (5,4,3,2,1)   # decimal digits low to high
69              $n = digit_split_lowtohigh (\@digits, 10);
70              # $n == 12345
71
72           Optional $zero can be a 0 of an overloaded number type such as
73           "Math::BigInt" to give a returned $n of that type.
74
75   Subclassing
76       "$aref = parameter_info_array()"
77           Return an arrayref of a "radix" parameter, default 2.  This is
78           designed to be imported into a PlanePath subclass as its
79           "parameter_info_array()" method.
80
81               package Math::PlanePath::MySubclass;
82               use Math::PlanePath::Base::Digits 'parameter_info_array';
83
84           The arrayref is
85
86               [ { name      => 'radix',
87                   share_key => 'radix_2',
88                   display   => 'Radix',
89                   type      => 'integer',
90                   minimum   => 2,
91                   default   => 2,
92                   width     => 3,
93                   description => 'Radix (number base).',
94                 }
95               ]
96
97       "$href = Math::PlanePath::Base::Digits::parameter_info_radix2()"
98           Return the single "radix" parameter hashref from the info above.
99           This can be used when a subclass wants the radix parameter and
100           other parameters too,
101
102               package Math::PlanePath::MySubclass;
103               use constant parameter_info_array =>
104                 [
105                  { name            => 'something_else',
106                    type            => 'integer',
107                    default         => '123',
108                  },
109                  Math::PlanePath::Base::Digits::parameter_info_radix2(),
110                 ];
111
112           If the "description" part should be more specific or more detailed
113           then it could be overridden with for example
114
115              { %{Math::PlanePath::Base::Digits::parameter_info_radix2()},
116                description => 'Radix, for both something and something.',
117              },
118
119           This function is not exportable since it's meant for a one-off call
120           in an initializer and so no need to import it for repeated use.
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HOME PAGE

128       <http://user42.tuxfamily.org/math-planepath/index.html>
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LICENSE

131       Copyright 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 Kevin Ryde
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133       This file is part of Math-PlanePath.
134
135       Math-PlanePath is free software; you can redistribute it and/or modify
136       it under the terms of the GNU General Public License as published by
137       the Free Software Foundation; either version 3, or (at your option) any
138       later version.
139
140       Math-PlanePath is distributed in the hope that it will be useful, but
141       WITHOUT ANY WARRANTY; without even the implied warranty of
142       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
143       General Public License for more details.
144
145       You should have received a copy of the GNU General Public License along
146       with Math-PlanePath.  If not, see <http://www.gnu.org/licenses/>.
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150perl v5.28.0                      2017-12-03  Math::PlanePath::Base::Digits(3)