Op 16 mrt. 2012 07:17 schreef "Jim Michaels" <[email protected]> het
volgende:
>
> 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...
C++11 is not "just another side standard. TR1 its the in-between thing
here. Did you try msvs2008's <tr1/random>? This bug might be a bug in the
tr1 description. Did you even try ideone for this? If it's present there,
chances are GCC or libstdc++ do nothing wrong, and instead tr1 is to blame.
Use c++11, seriously. But note not all compilers or compiler versions
implement everything. If your platforms don't have compiler or library
support for what you need, and if tr1 doesn't offer what you need, use
boost. It has everything you could wish for.
Ruben
>
> 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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