Re: [Boost-bugs] [Boost C++ Libraries] #10364: Release 1.56 broke random::uniform_real_distribution

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #10364: Release 1.56 broke random::uniform_real_distribution
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2016-02-16 03:03:15

#10364: Release 1.56 broke random::uniform_real_distribution
-------------------------------+---------------------------
  Reporter:  mouse008@…        |      Owner:  no-maintainer
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  random
   Version:  Boost 1.56.0      |   Severity:  Regression
Resolution:                    |   Keywords:
-------------------------------+---------------------------

Comment (by Mouse <mouse008@…>):

 Further checking shows that `uniform_real_distribution<> uc(-20.0, 20.0);`
 works (compiles and runs fine). `uniform_real_distribution<mpf_float_50>
 ur(-20.0, 20.0);` fails to compile (see attached output of compile
 attempt: `b-r6b.out`).

 This compiles and runs OK:

 {{{
 #include <iostream>
 #include <boost/multiprecision/gmp.hpp>
 #include <boost/multiprecision/random.hpp>

 using namespace boost::multiprecision;
 using namespace boost::random;

 int main() {

         unsigned long long myseed = 0x12345670;
         mt19937 rgen(myseed);
         uniform_real_distribution<> uc(-20.0, 20.0);

         std::cout << std::hex
         // << std::showbase
         ;

         //
         // Generate some values:
         //
         std::cout << std::setprecision(50);
         for(unsigned i = 0; i < 20; ++i)
                 std::cout << std::setw(2) << (i+1) << ": "
                           << std::setw(20)
                           << uc(rgen)
                           << std::endl;
         std::cout << std::endl;
 }
 }}}
 giving this output:

 {{{
 $ ./b-r6a
  1: 17.07083447836339473724365234375
  2: 18.59527722932398319244384765625
  3: 17.2086485661566257476806640625
  4: -7.10314041934907436370849609375
  5: 12.02050872147083282470703125
  6: 16.396274752914905548095703125
  7: 18.85700456798076629638671875
  8: 0.078481473028659820556640625
  9: 4.03215981088578701019287109375
  a: 3.56800344772636890411376953125
  b: 4.79332183487713336944580078125
  c: 0.429534278810024261474609375
  d: 13.35449189879000186920166015625
  e: -6.27208642661571502685546875
  f: 13.10226154513657093048095703125
 10: -8.06778541766107082366943359375
 11: 6.47328031249344348907470703125
 12: -9.097188748419284820556640625
 13: 16.7489224486052989959716796875
 14: 18.96312631666660308837890625
 }}}

 This does not compile (see the attached output):

 {{{
 #include <iostream>
 #include <boost/multiprecision/gmp.hpp>
 #include <boost/multiprecision/random.hpp>

 using namespace boost::multiprecision;
 using namespace boost::random;

 int main() {

         unsigned long long myseed = 0x12345670;
         mt19937 rgen(myseed);
         independent_bits_engine<mt19937, 100, mpf_float_50> gen3(rgen);
         uniform_real_distribution<mpf_float_50> ur(-20.0, 20.0);

         std::cout << std::hex
         // << std::showbase
         ;

         //
         // Generate some values:
         //
         std::cout << std::setprecision(50);
         for(unsigned i = 0; i < 20; ++i)
                 std::cout << std::setw(2) << (i+1) << ": "
                           << std::setw(20)
                           << ur(gen3) << "  "
                           << ur(rgen)
                           << std::endl;
         std::cout << std::endl;
 }
 }}}

 Unfortunately I cannot test the proposed commit because I'm not building
 Boost myself (any more). I have to wait until the fix percolates down to
 the distributions, and Macports picks it up. :-(

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10364#comment:4>
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