Re^2: is rand random enough to simulate dice rolls?

Fantastic kcott,

Here the win32 version of the oneliner, with added info about perl and OS:

perl -e "my $iters = 100_000; my $runs = 6; for my $sides (qw{1 2 3 4 
+6 8 10 20 100}) { printf '%-5s', qq(D$sides:); for (1 ..$runs) { my $
+tot = 0; for (1 .. $iters) { $tot += int(rand $sides)+1; } print ' ',
+ $tot/$iters; } print qq(\n); } print qq(Perl $^V $^O\n)"
[download]

And here are mine test results, all tests done in win10 and various strawberry protable:

# perl 5.26 64bit
D1:   1 1 1 1 1 1
D2:   1.49728 1.49979 1.49854 1.49977 1.50298 1.49972
D3:   2.00109 1.99922 1.99705 2.00131 2.00066 1.99933
D4:   2.49997 2.49926 2.49824 2.50176 2.49721 2.50158
D6:   3.49789 3.4945 3.50307 3.49706 3.49873 3.49967
D8:   4.50906 4.50074 4.49878 4.49863 4.49699 4.49534
D10:  5.50115 5.49664 5.49682 5.4829 5.48539 5.50885
D20:  10.48781 10.51603 10.53692 10.48499 10.4977 10.47859
D100: 50.43999 50.51722 50.4861 50.56783 50.49071 50.46732
Perl v5.26.0 MSWin32

# perl 5.20 64bit
D1:   1 1 1 1 1 1
D2:   1.50002 1.50098 1.50027 1.50081 1.50254 1.49815
D3:   1.9922 1.99659 1.99707 1.99924 1.99908 1.99999
D4:   2.49771 2.49966 2.50482 2.49946 2.49785 2.4987
D6:   3.50342 3.50138 3.4978 3.49477 3.50353 3.50182
D8:   4.49888 4.50591 4.50095 4.48605 4.49364 4.49382
D10:  5.50832 5.49959 5.49786 5.50018 5.49388 5.50274
D20:  10.49467 10.5032 10.48564 10.52528 10.45654 10.49782
D100: 50.60325 50.57722 50.53147 50.46864 50.53958 50.30884
Perl v5.20.3 MSWin32

#perl 5.22 64bit
D1:   1 1 1 1 1 1
D2:   1.4988 1.50017 1.50026 1.49912 1.50178 1.49942
D3:   2.00206 2.0024 2.00078 2.00151 1.99834 2.00194
D4:   2.50002 2.49894 2.49548 2.49825 2.50101 2.49567
D6:   3.49631 3.49881 3.49596 3.50121 3.50469 3.50556
D8:   4.50097 4.49576 4.50741 4.49163 4.50218 4.50035
D10:  5.48775 5.49495 5.49863 5.51452 5.50426 5.49525
D20:  10.49001 10.51559 10.46902 10.50395 10.47399 10.51619
D100: 50.4696 50.58086 50.56925 50.53794 50.45582 50.55695
Perl v5.22.3 MSWin32

#perl 5.24 64bit
D1:   1 1 1 1 1 1
D2:   1.50176 1.50093 1.50375 1.49886 1.49829 1.4978
D3:   1.99889 1.99722 2.00216 2.00232 1.99973 2.0025
D4:   2.50295 2.50345 2.50489 2.4964 2.49571 2.49994
D6:   3.50793 3.49375 3.49834 3.50353 3.49543 3.50472
D8:   4.48382 4.50156 4.50724 4.49537 4.50094 4.50467
D10:  5.50561 5.49698 5.50331 5.50191 5.51183 5.49333
D20:  10.51188 10.49523 10.51253 10.52995 10.52965 10.50506
D100: 50.4417 50.37094 50.4741 50.62746 50.53223 50.55502
Perl v5.24.2 MSWin32

#perl 5.26 64bit
D1:   1 1 1 1 1 1
D2:   1.49995 1.50071 1.49846 1.49906 1.49984 1.49977
D3:   2.00044 1.99638 1.9986 2.00209 2.00057 2.00021
D4:   2.50587 2.50951 2.49899 2.5003 2.50401 2.49556
D6:   3.49642 3.49724 3.50929 3.49369 3.49324 3.50481
D8:   4.48084 4.49379 4.50828 4.50079 4.50653 4.50257
D10:  5.49304 5.50007 5.51128 5.51153 5.49389 5.49713
D20:  10.46065 10.49741 10.49662 10.50199 10.5104 10.50549
D100: 50.48183 50.38416 50.41408 50.47176 50.30296 50.53482
Perl v5.26.0 MSWin32

#perl 5.26 64bit PDL version
D1:   1 1 1 1 1 1
D2:   1.49836 1.50338 1.4989 1.50025 1.49961 1.49982
D3:   1.9985 2.00365 2.00221 1.99604 2.00141 1.99762
D4:   2.5029 2.50257 2.49807 2.5005 2.49348 2.49663
D6:   3.50266 3.50063 3.50627 3.48774 3.5096 3.50361
D8:   4.504 4.48456 4.49345 4.50077 4.50083 4.50001
D10:  5.50843 5.50186 5.49619 5.50336 5.49785 5.50342
D20:  10.50045 10.44466 10.5242 10.50923 10.50356 10.51332
D100: 50.39945 50.51811 50.47581 50.44648 50.4911 50.47012
Perl v5.26.2 MSWin32
[download]

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

Comment on Re^2: is rand random enough to simulate dice rolls? Select or Download Code

Replies are listed 'Best First'.
Re^3: is rand random enough to simulate dice rolls? by etj (Priest) on Apr 18, 2022 at 19:44 UTC
I saw this post while looking up old PDL nodes, and you mentioned PDL there. PDL as of 2.062 uses a "better" (and thread-safe, for potential massive performance gainz) pseudo-random number generator, xoroshiro256plus (see link for thorough statistical analysis of it and competing algorithms) rather than the often-weak and usually non-thread-safe system `rand()` that Perl uses.	[reply] [d/l]
Re^3: is rand random enough to simulate dice rolls? by shmem (Chancellor) on Jan 04, 2021 at 08:55 UTC
And here are mine test results, all tests done in win10 and various strawberry protable: And your conclusion is? It looks to me like all those perls are pretty well behaved, including my old ones (see above). perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'	[reply]
Re^4: is rand random enough to simulate dice rolls? by Discipulus (Canon) on Jan 04, 2021 at 11:50 UTC
Hello shmem, > And your conclusion is? It looks to me like all those perls are pretty well behaved, including my old ones Yes it seems so. My conclusion was in Re^2: is rand random enough to simulate dice rolls?: as haukex and other said is unwise to break a test for something related to a core function which might have problems in preistoric installations. A big warning, as above, is more than nothing in case of test failure. L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l]