xref: /openbsd-src/gnu/usr.bin/perl/cpan/Math-BigInt/t/biglog.t (revision d13be5d47e4149db2549a9828e244d59dbc43f15)
1#!/usr/bin/perl -w
2
3# Test blog function (and bpow, since it uses blog), as well as bexp().
4
5# It is too slow to be simple included in bigfltpm.inc, where it would get
6# executed 3 times. One time would be under BareCalc, which shouldn't make any
7# difference since there is no CALC->_log() function, and one time under a
8# subclass, which *should* work.
9
10# But it is better to test the numerical functionality, instead of not testing
11# it at all (which did lead to wrong answers for 0 < $x < 1 in blog() in
12# versions up to v1.63, and for bsqrt($x) when $x << 1 for instance).
13
14use Test::More;
15use strict;
16
17BEGIN
18  {
19  $| = 1;
20  # to locate the testing files
21  my $location = $0; $location =~ s/biglog.t//i;
22  if ($ENV{PERL_CORE})
23    {
24    # testing with the core distribution
25    @INC = qw(../lib);
26    }
27  unshift @INC, '../lib';
28  if (-d 't')
29    {
30    chdir 't';
31    require File::Spec;
32    unshift @INC, File::Spec->catdir(File::Spec->updir, $location);
33    }
34  else
35    {
36    unshift @INC, $location;
37    }
38  print "# INC = @INC\n";
39
40  plan tests => 70;
41  }
42
43use Math::BigFloat;
44use Math::BigInt;
45
46my $cl = "Math::BigInt";
47
48#############################################################################
49# test log($n) in BigInt (broken until 1.80)
50
51is ($cl->new(2)->blog(), '0', "blog(2)");
52is ($cl->new(288)->blog(), '5',"blog(288)");
53is ($cl->new(2000)->blog(), '7', "blog(2000)");
54
55#############################################################################
56# test exp($n) in BigInt
57
58is ($cl->new(1)->bexp(), '2', "bexp(1)");
59is ($cl->new(2)->bexp(), '7',"bexp(2)");
60is ($cl->new(3)->bexp(), '20', "bexp(3)");
61
62#############################################################################
63#############################################################################
64# BigFloat tests
65
66#############################################################################
67# test log(2, N) where N > 67 (broken until 1.82)
68
69$cl = "Math::BigFloat";
70
71# These tests can take quite a while, but are nec. Maybe protect them with
72# some alarm()?
73
74# this triggers the calculation and caching of ln(2):
75ok ($cl->new(5)->blog(undef,71),
76'1.6094379124341003746007593332261876395256013542685177219126478914741790');
77
78# if the cache was correct, we should get this result, fast:
79ok ($cl->new(2)->blog(undef,71),
80'0.69314718055994530941723212145817656807550013436025525412068000949339362');
81
82ok ($cl->new(10)->blog(undef,71),
83'2.3025850929940456840179914546843642076011014886287729760333279009675726');
84
85ok ($cl->new(21)->blog(undef,71),
86'3.0445224377234229965005979803657054342845752874046106401940844835750742');
87
88#############################################################################
89
90# These tests are now really fast, since they collapse to blog(10), basically
91# Don't attempt to run them with older versions. You are warned.
92
93# $x < 0 => NaN
94ok ($cl->new(-2)->blog(), 'NaN');
95ok ($cl->new(-1)->blog(), 'NaN');
96ok ($cl->new(-10)->blog(), 'NaN');
97ok ($cl->new(-2,2)->blog(), 'NaN');
98
99my $ten = $cl->new(10)->blog();
100
101# 10 is cached (up to 75 digits)
102ok ($cl->new(10)->blog(), '2.302585092994045684017991454684364207601');
103
104# 0.1 is using the cached value for log(10), too
105
106ok ($cl->new(0.1)->blog(), -$ten);
107ok ($cl->new(0.01)->blog(), -$ten * 2);
108ok ($cl->new(0.001)->blog(), -$ten * 3);
109ok ($cl->new(0.0001)->blog(), -$ten * 4);
110
111# also cached
112ok ($cl->new(2)->blog(), '0.6931471805599453094172321214581765680755');
113ok ($cl->new(4)->blog(), $cl->new(2)->blog * 2);
114
115# These are still slow, so do them only to 10 digits
116
117ok ($cl->new('0.2')->blog(undef,10), '-1.609437912');
118ok ($cl->new('0.3')->blog(undef,10), '-1.203972804');
119ok ($cl->new('0.4')->blog(undef,10), '-0.9162907319');
120ok ($cl->new('0.5')->blog(undef,10), '-0.6931471806');
121ok ($cl->new('0.6')->blog(undef,10), '-0.5108256238');
122ok ($cl->new('0.7')->blog(undef,10), '-0.3566749439');
123ok ($cl->new('0.8')->blog(undef,10), '-0.2231435513');
124ok ($cl->new('0.9')->blog(undef,10), '-0.1053605157');
125
126ok ($cl->new('9')->blog(undef,10), '2.197224577');
127
128ok ($cl->new('10')->blog(10,10),   '1.000000000');
129ok ($cl->new('20')->blog(20,10),   '1.000000000');
130ok ($cl->new('100')->blog(100,10), '1.000000000');
131
132ok ($cl->new('100')->blog(10,10),  '2.000000000');	# 10 ** 2 == 100
133ok ($cl->new('400')->blog(20,10),  '2.000000000');	# 20 ** 2 == 400
134
135ok ($cl->new('4')->blog(2,10),  '2.000000000');		# 2 ** 2 == 4
136ok ($cl->new('16')->blog(2,10), '4.000000000');		# 2 ** 4 == 16
137
138ok ($cl->new('1.2')->bpow('0.3',10),  '1.056219968');
139ok ($cl->new('10')->bpow('0.6',10),   '3.981071706');
140
141# blog should handle bigint input
142is (Math::BigFloat::blog(Math::BigInt->new(100),10), 2, "blog(100)");
143
144#############################################################################
145# some integer results
146is ($cl->new(2)->bpow(32)->blog(2),  '32', "2 ** 32");
147is ($cl->new(3)->bpow(32)->blog(3),  '32', "3 ** 32");
148is ($cl->new(2)->bpow(65)->blog(2),  '65', "2 ** 65");
149
150my $x = Math::BigInt->new( '777' ) ** 256;
151my $base = Math::BigInt->new( '12345678901234' );
152is ($x->copy()->blog($base), 56, 'blog(777**256, 12345678901234)');
153
154$x = Math::BigInt->new( '777' ) ** 777;
155$base = Math::BigInt->new( '777' );
156is ($x->copy()->blog($base), 777, 'blog(777**777, 777)');
157
158#############################################################################
159# test for bug in bsqrt() not taking negative _e into account
160test_bpow ('200','0.5',10,      '14.14213562');
161test_bpow ('20','0.5',10,       '4.472135955');
162test_bpow ('2','0.5',10,        '1.414213562');
163test_bpow ('0.2','0.5',10,      '0.4472135955');
164test_bpow ('0.02','0.5',10,     '0.1414213562');
165test_bpow ('0.49','0.5',undef , '0.7');
166test_bpow ('0.49','0.5',10 ,    '0.7000000000');
167test_bpow ('0.002','0.5',10,    '0.04472135955');
168test_bpow ('0.0002','0.5',10,   '0.01414213562');
169test_bpow ('0.0049','0.5',undef,'0.07');
170test_bpow ('0.0049','0.5',10 ,  '0.07000000000');
171test_bpow ('0.000002','0.5',10, '0.001414213562');
172test_bpow ('0.021','0.5',10,    '0.1449137675');
173test_bpow ('1.2','0.5',10,      '1.095445115');
174test_bpow ('1.23','0.5',10,     '1.109053651');
175test_bpow ('12.3','0.5',10,     '3.507135583');
176
177test_bpow ('9.9','0.5',10,        '3.146426545');
178test_bpow ('9.86902225','0.5',10, '3.141500000');
179test_bpow ('9.86902225','0.5',undef, '3.1415');
180
181test_bpow ('0.2','0.41',10,   '0.5169187652');
182
183#############################################################################
184# test bexp() with cached results
185
186is ($cl->new(1)->bexp(), '2.718281828459045235360287471352662497757', 'bexp(1)');
187is ($cl->new(2)->bexp(40), $cl->new(1)->bexp(45)->bpow(2,40), 'bexp(2)');
188
189is ($cl->new("12.5")->bexp(61), $cl->new(1)->bexp(65)->bpow(12.5,61), 'bexp(12.5)');
190
191#############################################################################
192# test bexp() with big values (non-cached)
193
194is ($cl->new(1)->bexp(100),
195  '2.718281828459045235360287471352662497757247093699959574966967627724076630353547594571382178525166427',
196 'bexp(100)');
197
198is ($cl->new("12.5")->bexp(91), $cl->new(1)->bexp(95)->bpow(12.5,91),
199  'bexp(12.5) to 91 digits');
200
201# all done
2021;
203
204#############################################################################
205sub test_bpow
206  {
207  my ($x,$y,$scale,$result) = @_;
208
209  print "# Tried: $x->bpow($y,$scale);\n"
210   unless ok ($cl->new($x)->bpow($y,$scale),$result);
211  }
212
213
214