[Boost-commit] svn:boost r73612 - in sandbox/big_number: boost/math/big_number libs/math/test

Subject: [Boost-commit] svn:boost r73612 - in sandbox/big_number: boost/math/big_number libs/math/test
From: john_at_[hidden]
Date: 2011-08-08 13:13:51

Author: johnmaddock
Date: 2011-08-08 13:13:50 EDT (Mon, 08 Aug 2011)
New Revision: 73612
URL: http://svn.boost.org/trac/boost/changeset/73612

Log:
Add ldexp and frexp.
Text files modified: 
   sandbox/big_number/boost/math/big_number/gmp.hpp      |    24 ++++++++++++++++++++++++                
   sandbox/big_number/libs/math/test/test_arithmetic.cpp |    15 +++++++++++++++                         
   2 files changed, 39 insertions(+), 0 deletions(-)

Modified: sandbox/big_number/boost/math/big_number/gmp.hpp
==============================================================================
--- sandbox/big_number/boost/math/big_number/gmp.hpp	(original)
+++ sandbox/big_number/boost/math/big_number/gmp.hpp	2011-08-08 13:13:50 EDT (Mon, 08 Aug 2011)
@@ -413,6 +413,30 @@
    mpf_trunc(result.backend().data(), val.backend().data());
    return result;
 }
+template <unsigned Digits10>
+big_number<gmp_real<Digits10> > ldexp(const big_number<gmp_real<Digits10> >& val, long e)
+{
+   big_number<gmp_real<Digits10> > result;
+   if(e > 0)
+      mpf_mul_2exp(result.backend().data(), val.backend().data(), e);
+   else if(e < 0)
+      mpf_div_2exp(result.backend().data(), val.backend().data(), -e);
+   return result;
+}
+template <unsigned Digits10>
+big_number<gmp_real<Digits10> > frexp(const big_number<gmp_real<Digits10> >& val, int* e)
+{
+   long v;
+   mpf_get_d_2exp(&v, val.backend().data());
+   *e = v;
+   return ldexp(val, -v);
+}
+template <unsigned Digits10>
+big_number<gmp_real<Digits10> > frexp(const big_number<gmp_real<Digits10> >& val, long* e)
+{
+   mpf_get_d_2exp(e, val.backend().data());
+   return ldexp(val, -*v);
+}
 
 struct gmp_int
 {

Modified: sandbox/big_number/libs/math/test/test_arithmetic.cpp
==============================================================================
--- sandbox/big_number/libs/math/test/test_arithmetic.cpp	(original)
+++ sandbox/big_number/libs/math/test/test_arithmetic.cpp	2011-08-08 13:13:50 EDT (Mon, 08 Aug 2011)
@@ -85,6 +85,21 @@
    BOOST_TEST(ceil(Real(-5) / 2) == -2);
    BOOST_TEST(trunc(Real(5) / 2) == 2);
    BOOST_TEST(trunc(Real(-5) / 2) == -2);
+
+   //
+   // ldexp and frexp, these pretty much have to implemented by each backend:
+   //
+   BOOST_TEST(ldexp(Real(2), 5) == 64);
+   BOOST_TEST(ldexp(Real(2), -5) == Real(2) / 32);
+   Real v(512);
+   int exp;
+   Real r = frexp(v, &exp);
+   BOOST_TEST(r == 0.5);
+   BOOST_TEST(exp == 10);
+   v = 1 / v;
+   r = frexp(v, &exp);
+   BOOST_TEST(r == 0.5);
+   BOOST_TEST(exp == -8);
 }
 
 template <class Real, class Num>