Math::BigRat(3pm)

1Math::BigRat(3pm)      Perl Programmers Reference Guide      Math::BigRat(3pm)
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NAME

6       Math::BigRat - Arbitrary big rational numbers
7

SYNOPSIS

9               use Math::BigRat;
10
11               my $x = Math::BigRat->new('3/7'); $x += '5/9';
12
13               print $x->bstr(),"\n";
14               print $x ** 2,"\n";
15
16               my $y = Math::BigRat->new('inf');
17               print "$y ", ($y->is_inf ? 'is' : 'is not') , " infinity\n";
18
19               my $z = Math::BigRat->new(144); $z->bsqrt();
20

DESCRIPTION

22       Math::BigRat complements Math::BigInt and Math::BigFloat by providing
23       support for arbitrary big rational numbers.
24
25       MATH LIBRARY
26
27       Math with the numbers is done (by default) by a module called
28       Math::BigInt::Calc. This is equivalent to saying:
29
30               use Math::BigRat lib => 'Calc';
31
32       You can change this by using:
33
34               use Math::BigRat lib => 'BitVect';
35
36       The following would first try to find Math::BigInt::Foo, then
37       Math::BigInt::Bar, and when this also fails, revert to Math::Big‐
38       Int::Calc:
39
40               use Math::BigRat lib => 'Foo,Math::BigInt::Bar';
41
42       Calc.pm uses as internal format an array of elements of some decimal
43       base (usually 1e7, but this might be different for some systems) with
44       the least significant digit first, while BitVect.pm uses a bit vector
45       of base 2, most significant bit first. Other modules might use even
46       different means of representing the numbers. See the respective module
47       documentation for further details.
48
49       Currently the following replacement libraries exist, search for them at
50       CPAN:
51
52               Math::BigInt::BitVect
53               Math::BigInt::GMP
54               Math::BigInt::Pari
55               Math::BigInt::FastCalc
56

METHODS

58       Any methods not listed here are dervied from Math::BigFloat (or
59       Math::BigInt), so make sure you check these two modules for further
60       information.
61
62       new()
63
64               $x = Math::BigRat->new('1/3');
65
66       Create a new Math::BigRat object. Input can come in various forms:
67
68               $x = Math::BigRat->new(123);                            # scalars
69               $x = Math::BigRat->new('inf');                          # infinity
70               $x = Math::BigRat->new('123.3');                        # float
71               $x = Math::BigRat->new('1/3');                          # simple string
72               $x = Math::BigRat->new('1 / 3');                        # spaced
73               $x = Math::BigRat->new('1 / 0.1');                      # w/ floats
74               $x = Math::BigRat->new(Math::BigInt->new(3));           # BigInt
75               $x = Math::BigRat->new(Math::BigFloat->new('3.1'));     # BigFloat
76               $x = Math::BigRat->new(Math::BigInt::Lite->new('2'));   # BigLite
77
78               # You can also give D and N as different objects:
79               $x = Math::BigRat->new(
80                       Math::BigInt->new(-123),
81                       Math::BigInt->new(7),
82                       );                      # => -123/7
83
84       numerator()
85
86               $n = $x->numerator();
87
88       Returns a copy of the numerator (the part above the line) as signed
89       BigInt.
90
91       denominator()
92
93               $d = $x->denominator();
94
95       Returns a copy of the denominator (the part under the line) as positive
96       BigInt.
97
98       parts()
99
100               ($n,$d) = $x->parts();
101
102       Return a list consisting of (signed) numerator and (unsigned) denomina‐
103       tor as BigInts.
104
105       as_int()
106
107               $x = Math::BigRat->new('13/7');
108               print $x->as_int(),"\n";                # '1'
109
110       Returns a copy of the object as BigInt, truncated to an integer.
111
112       "as_number()" is an alias for "as_int()".
113
114       as_hex()
115
116               $x = Math::BigRat->new('13');
117               print $x->as_hex(),"\n";                # '0xd'
118
119       Returns the BigRat as hexadecimal string. Works only for integers.
120
121       as_bin()
122
123               $x = Math::BigRat->new('13');
124               print $x->as_bin(),"\n";                # '0x1101'
125
126       Returns the BigRat as binary string. Works only for integers.
127
128       bfac()
129
130               $x->bfac();
131
132       Calculates the factorial of $x. For instance:
133
134               print Math::BigRat->new('3/1')->bfac(),"\n";    # 1*2*3
135               print Math::BigRat->new('5/1')->bfac(),"\n";    # 1*2*3*4*5
136
137       Works currently only for integers.
138
139       blog()
140
141       Is not yet implemented.
142
143       bround()/round()/bfround()
144
145       Are not yet implemented.
146
147       bmod()
148
149               use Math::BigRat;
150               my $x = Math::BigRat->new('7/4');
151               my $y = Math::BigRat->new('4/3');
152               print $x->bmod($y);
153
154       Set $x to the remainder of the division of $x by $y.
155
156       is_one()
157
158               print "$x is 1\n" if $x->is_one();
159
160       Return true if $x is exactly one, otherwise false.
161
162       is_zero()
163
164               print "$x is 0\n" if $x->is_zero();
165
166       Return true if $x is exactly zero, otherwise false.
167
168       is_pos()
169
170               print "$x is >= 0\n" if $x->is_positive();
171
172       Return true if $x is positive (greater than or equal to zero), other‐
173       wise false. Please note that '+inf' is also positive, while 'NaN' and
174       '-inf' aren't.
175
176       "is_positive()" is an alias for "is_pos()".
177
178       is_neg()
179
180               print "$x is < 0\n" if $x->is_negative();
181
182       Return true if $x is negative (smaller than zero), otherwise false.
183       Please note that '-inf' is also negative, while 'NaN' and '+inf'
184       aren't.
185
186       "is_negative()" is an alias for "is_neg()".
187
188       is_int()
189
190               print "$x is an integer\n" if $x->is_int();
191
192       Return true if $x has a denominator of 1 (e.g. no fraction parts), oth‐
193       erwise false. Please note that '-inf', 'inf' and 'NaN' aren't integer.
194
195       is_odd()
196
197               print "$x is odd\n" if $x->is_odd();
198
199       Return true if $x is odd, otherwise false.
200
201       is_even()
202
203               print "$x is even\n" if $x->is_even();
204
205       Return true if $x is even, otherwise false.
206
207       bceil()
208
209               $x->bceil();
210
211       Set $x to the next bigger integer value (e.g. truncate the number to
212       integer and then increment it by one).
213
214       bfloor()
215
216               $x->bfloor();
217
218       Truncate $x to an integer value.
219
220       bsqrt()
221
222               $x->bsqrt();
223
224       Calculate the square root of $x.
225
226       config
227
228               use Data::Dumper;
229
230               print Dumper ( Math::BigRat->config() );
231               print Math::BigRat->config()->{lib},"\n";
232
233       Returns a hash containing the configuration, e.g. the version number,
234       lib loaded etc. The following hash keys are currently filled in with
235       the appropriate information.
236
237               key             RO/RW   Description
238                                       Example
239               ============================================================
240               lib             RO      Name of the Math library
241                                       Math::BigInt::Calc
242               lib_version     RO      Version of 'lib'
243                                       0.30
244               class           RO      The class of config you just called
245                                       Math::BigRat
246               version         RO      version number of the class you used
247                                       0.10
248               upgrade         RW      To which class numbers are upgraded
249                                       undef
250               downgrade       RW      To which class numbers are downgraded
251                                       undef
252               precision       RW      Global precision
253                                       undef
254               accuracy        RW      Global accuracy
255                                       undef
256               round_mode      RW      Global round mode
257                                       even
258               div_scale       RW      Fallback acccuracy for div
259                                       40
260               trap_nan        RW      Trap creation of NaN (undef = no)
261                                       undef
262               trap_inf        RW      Trap creation of +inf/-inf (undef = no)
263                                       undef
264
265       By passing a reference to a hash you may set the configuration values.
266       This works only for values that a marked with a "RW" above, anything
267       else is read-only.
268

BUGS

270       Some things are not yet implemented, or only implemented half-way:
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272       inf handling (partial)
273       NaN handling (partial)
274       rounding (not implemented except for bceil/bfloor)
275       $x ** $y where $y is not an integer
276       bmod(), blog(), bmodinv() and bmodpow() (partial)
277

LICENSE

279       This program is free software; you may redistribute it and/or modify it
280       under the same terms as Perl itself.
281

AUTHORS

293       (C) by Tels <http://bloodgate.com/> 2001 - 2005.
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297perl v5.8.8                       2001-09-21                 Math::BigRat(3pm)