do you submit a bug report anyway since this is in every compiler and tr1
examples abound? many people like me think you are supposed to be using tr1
and that c++11 is just another side standard, not something that encompasses...
it's still a bug, even if you choose to ignore it, and it still affects
people. possibly a lot of people due to the Internet's varying page ages.
>________________________________
> From: Ruben Van Boxem <[email protected]>
>To: [email protected]
>Sent: Thursday, March 15, 2012 12:47 AM
>Subject: Re: [Mingw-w64-public] problem with <random>'s uniform_int?
>
>
>Op 15 mrt. 2012 03:31 schreef "K. Frank" <[email protected]> het volgende:
>>
>> Hello Jim and Kai and Ruben and Friends!
>>
>> I see something similar to Jim's bug in <tr1/random>, but
>> not in <random>.
>>
>> On Wed, Mar 14, 2012 at 2:22 AM, Jim Michaels <[email protected]> wrote:
>> > /*
>> > Author: Jim Michaels
>> > ...
>> > #include <tr1/random>
>> > ...
>> > //problem: this hovers way too long around
>> > /*
>> > sample output:
>> > 18446744072913795932
>> > 18446744073304931054
>> > 18446744073000918905
>> > 18446744073575839711
>> > 18446744073337503749
>> > ...
>>
>> First, Jim's observation does look like a bug to me. I don't see anything
>> in his code that looks wrong (but I often overlook things).
>>
>> Also, when I run a similar test program, I see a similar problem when I
>> use <tr1/random>:
>>
>> 00000000003499211612
>> 00000000000581869302
>> 00000000003890346734
>> 00000000003586334585
>> 00000000000545404204
>>
>> but not when I use <random>.
>>
>> 15028999435905310454
>> 16708911996216745849
>> 02342493223442167775
>> 16848810653347327969
>> 11664969248402573611
>>
>> (One speculation on the difference between Jim's bug observation
>> and mine: Maybe the high-order word isn't getting set by uniform_int,
>> and for some reason Jim is getting garbage in the high-order word,
>> while I am getting zero.)
>>
>> My complete program and output follow, below.
>>
>> Note, I am using one of Ruben's std::thread-enabled 4.7.0 64-bit
>> builds.
>>
>> I suppose that there is a bug, but if I'm right that it's only in
>> <tr1/random>, I'm not sure how much we care. Maybe the
>> bug fix should be to junk tr1. I don't have much appetite for
>> investigating tr1 any further as c++11's <random> seems to
>> be working correctly in this regard.
>If the real <random> header does work correctly, this is indeed also my stance
>on the subject. Tr1 is old, c++11's real headers, which are available
>everywhere you could wish for, replace and improve every bit of functionality
>provided by tr1. Stop using tr1.
>Thanks for the test,
>Ruben
>>
>> > ...
>> > Jim Michaels
>> > ...
>>
>> Thanks for bringing this up, and Happy Hacking!
>>
>> K. Frank
>>
>> --- program details ---
>>
>> C:\random_test>type uniform_test.cpp
>> #include <iostream>
>> #include <random>
>> #include <tr1/random>
>>
>> int main () {
>> std::cout << "<random>..." << std::endl;
>> std::mt19937 mte;
>> std::uniform_int_distribution<unsigned long long> ull_dist {0ULL,
>> 0xffffffffffffffffULL};
>>
>> for (unsigned i = 0; i < 10; i++) {
>> std::cout.fill('0');
>> std::cout.width(20);
>> std::cout << ull_dist (mte) << std::endl;
>> }
>>
>> std::cout << "<tr1/random>..." << std::endl;
>> std::tr1::mt19937 mte2;
>> std::tr1::uniform_int<unsigned long long> ull_dist2 {0ULL,
>> 0xffffffffffffffffULL};
>>
>> for (unsigned i = 0; i < 10; i++) {
>> std::cout.fill('0');
>> std::cout.width(20);
>> std::cout << ull_dist2 (mte2) << std::endl;
>> }
>>
>> return 0;
>> }
>>
>> C:\random_test>g++ --version
>> g++ (GCC) 4.7.0 20110829 (experimental)
>> Copyright (C) 2011 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions. There is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>>
>>
>> C:\random_test>g++ -std=c++0x -o uniform_test uniform_test.cpp
>>
>> C:\random_test>uniform_test
>> <random>...
>> 15028999435905310454
>> 16708911996216745849
>> 02342493223442167775
>> 16848810653347327969
>> 11664969248402573611
>> 01799302827895858725
>> 05137385360522333466
>> 10088183424363624464
>> 17662883439475955428
>> 17799051847008967418
>> <tr1/random>...
>> 00000000003499211612
>> 00000000000581869302
>> 00000000003890346734
>> 00000000003586334585
>> 00000000000545404204
>> 00000000004161255391
>> 00000000003922919429
>> 00000000000949333985
>> 00000000002715962298
>> 00000000001323567403
>>
>> C:\random_test>
>>
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