[Boost-commit] svn:boost r79857 - sandbox/big_number/libs/multiprecision/performance

Subject: [Boost-commit] svn:boost r79857 - sandbox/big_number/libs/multiprecision/performance
From: john_at_[hidden]
Date: 2012-08-03 08:18:11

Author: johnmaddock
Date: 2012-08-03 08:18:10 EDT (Fri, 03 Aug 2012)
New Revision: 79857
URL: http://svn.boost.org/trac/boost/changeset/79857

Log:
Fix buglets in performance test code.
Explain delaunay code digit usage better.
Text files modified: 
   sandbox/big_number/libs/multiprecision/performance/delaunay_test.cpp  |    17 ++++++++++-------                       
   sandbox/big_number/libs/multiprecision/performance/sf_performance.cpp |     1 +                                       
   2 files changed, 11 insertions(+), 7 deletions(-)

Modified: sandbox/big_number/libs/multiprecision/performance/delaunay_test.cpp
==============================================================================
--- sandbox/big_number/libs/multiprecision/performance/delaunay_test.cpp	(original)
+++ sandbox/big_number/libs/multiprecision/performance/delaunay_test.cpp	2012-08-03 08:18:10 EDT (Fri, 03 Aug 2012)
@@ -129,12 +129,12 @@
 }
 
 template <class R, class T>
-inline void mul_2n(R& r, const T& a, const T& b)
+__forceinline void mul_2n(R& r, const T& a, const T& b)
 {
    r = R(a) * b;
 }
 
-inline void mul_2n(int128_t& r, const boost::int64_t& a, const boost::int64_t& b)
+__forceinline void mul_2n(int128_t& r, const boost::int64_t& a, const boost::int64_t& b)
 {
    r = mult_64x64_to_128(a, b);
 }
@@ -152,14 +152,17 @@
    // to the following code.
    // Numerical robustness is important.  This code addresses it by performing 
    // exact calculations with large integer types.
+   //
+   // NOTE: This routine is limited to inputs with up to 30 BIT PRECISION, which
+   // is to say all inputs must be in the range [INT_MIN/2, INT_MAX/2].
 
    typedef typename Traits::i64_t i64;
    typedef typename Traits::i128_t i128;
 
    i64 cos_abc, t;
-   mul_2n(cos_abc, (ax-bx), (cx-bx));
+   mul_2n(cos_abc, (ax-bx), (cx-bx));  // subtraction yields 31-bit values, multiplied to give 62-bit values
    mul_2n(t, (ay-by), (cy-by));
-   cos_abc += t;
+   cos_abc += t;   // addition yields 63 bit value, leaving one left for the sign
 
    i64 cos_cda;
    mul_2n(cos_cda, (cx-dx), (ax-dx));
@@ -180,9 +183,9 @@
    sin_cda -= t;
 
    i128 sin_sum, t128;
-   mul_2n(sin_sum, sin_abc, cos_cda);
+   mul_2n(sin_sum, sin_abc, cos_cda);  // 63-bit inputs multiplied to 126-bit output
    mul_2n(t128, cos_abc, sin_cda);
-   sin_sum += t128;
+   sin_sum += t128;  // Addition yields 127 bit result, leaving one bit for the sign
 
    return sin_sum < 0;
 }
@@ -266,7 +269,7 @@
    std::cout << "calculating...\n";
 
    do_calc<test_traits<boost::int64_t, boost::int64_t> >("int64_t, int64_t");
-   do_calc<test_traits<mp_number<arithmetic_backend<boost::int64_t> >, mp_number<arithmetic_backend<boost::int64_t> > > >("arithmetic_backend<int64_t>");
+   do_calc<test_traits<mp_number<arithmetic_backend<boost::int64_t>, false>, mp_number<arithmetic_backend<boost::int64_t>, false> > >("arithmetic_backend<int64_t>");
    do_calc<test_traits<boost::int64_t, int128_t> >("int64_t, int128_t");
    do_calc<test_traits<boost::int64_t, mp_int128_t> >("int64_t, mp_int128_t");
    do_calc<test_traits<boost::int64_t, mp_number<cpp_int_backend<128, true, void>, true> > >("int64_t, mp_int128_t (ET)");

Modified: sandbox/big_number/libs/multiprecision/performance/sf_performance.cpp
==============================================================================
--- sandbox/big_number/libs/multiprecision/performance/sf_performance.cpp	(original)
+++ sandbox/big_number/libs/multiprecision/performance/sf_performance.cpp	2012-08-03 08:18:10 EDT (Fri, 03 Aug 2012)
@@ -4,6 +4,7 @@
 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_
 
 #define BOOST_MATH_MAX_ROOT_ITERATION_POLICY 500
+#define BOOST_MATH_PROMOTE_DOUBLE_POLICY false
 
 #if !defined(TEST_MPFR) && !defined(TEST_MPREAL) && !defined(TEST_MPF) && !defined(TEST_MPREAL) \
    && !defined(TEST_CPP_DEC_FLOAT) && !defined(TEST_MPFR_CLASS) && !defined(TEST_FLOAT)