[lmi-commits] [lmi] master 041ca2fb 5/5: Add a measurement

[Greg Chicares]

branch: master
commit 041ca2fb1e5074069664d56abab4b377efe9e9ae
Author: Gregory W. Chicares <gchicares@sbcglobal.net>
Commit: Gregory W. Chicares <gchicares@sbcglobal.net>

    Add a measurement
    
    Production uses a template with a parameter of some floating-point type,
    so show results for both 'double' and 'long double' types. Incidentally
    improved output formatting.
    
    This is important because all pc-linux-gnu and msw system_test '.test'
    files differ, due mainly or perhaps entirely to monthly interest rates.
    If such discrepancies can be removed, then either test is as accurate
    as the other, and the timings:
      44.382  x86_64-w64-mingw32
      13.146  x86_64-pc-linux-gnu
    suggest which one is more practical to run many times per commit during
    development.
    
    The output for both architectures is copied here because it is
    interesting in more than one way:
     - all of the "Daily rate" calculations match except only those labelled
         "double precision, production template"
     - glibc's pow() is much slower, and its expm1() much faster, so the
         library routines used by MinGW-w64 must differ greatly
    
    x86_64, sse, gcc, posix
    
    Speed tests:
      std::pow         2.189e-01 s mean;     214245 us least of   5 runs
      std::expm1       2.059e-02 s mean;      20151 us least of  49 runs
      double      i365 2.790e-03 s mean;       2729 us least of 100 runs
      long double i365 1.421e-02 s mean;      13897 us least of  71 runs
      10^-9 nonstd     4.634e-04 s mean;        438 us least of 100 runs
      10^-9 std        2.180e-03 s mean;       2127 us least of 100 runs
    
    Daily rate corresponding to 1% annual interest, by various methods:
          000000000111111111122
          123456789012345678901
      0.00327373978219886392598  long double prec, production template
      0.00327373978219886392598  long double prec, std::expm1 and std::log1p
      0.00327373978219886395923  long double prec, std::pow
      0.00327373978219886374239  double prec, production template
      0.00327373978219886330870  double prec, std::expm1 and std::log1p
      0.00327373978219891448305  double prec, std::pow
    
    x86_64, sse, gcc, msw
    
    Speed tests:
      std::pow         6.926e-02 s mean;      67563 us least of  15 runs
      std::expm1       4.424e-02 s mean;      43520 us least of  23 runs
      double      i365 6.839e-03 s mean;       6735 us least of 100 runs
      long double i365 7.930e-03 s mean;       7771 us least of 100 runs
      10^-9 nonstd     4.520e-04 s mean;        438 us least of 100 runs
      10^-9 std        2.402e-03 s mean;       2255 us least of 100 runs
    
    Daily rate corresponding to 1% annual interest, by various methods:
          000000000111111111122
          123456789012345678901
      0.00327373978219886392598  long double prec, production template
      0.00327373978219886392598  long double prec, std::expm1 and std::log1p
      0.00327373978219886395923  long double prec, std::pow
      0.00327373978219886417607  double prec, production template
      0.00327373978219886330870  double prec, std::expm1 and std::log1p
      0.00327373978219891448305  double prec, std::pow
---
 math_functions_test.cpp | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/math_functions_test.cpp b/math_functions_test.cpp
index ec5862af..c2795f1e 100644
--- a/math_functions_test.cpp
+++ b/math_functions_test.cpp
@@ -167,31 +167,33 @@ void sample_results()
     std::cout.setf(std::ios_base::fixed, std::ios_base::floatfield);
     std::cout.precision(23);
     std::cout
-        << "\nDaily rate corresponding to 1% annual interest"
+        << "Daily rate corresponding to 1% annual interest"
         << ", by various methods:\n"
         << "      000000000111111111122\n"
         << "      123456789012345678901\n"
         << "  " << i_upper_n_over_n_from_i      <long double,12>()(intrate)
-        << "  method in production\n"
+        << "  long double prec, production template\n"
         ;
 #if defined LMI_X87
     fenv_precision(fe_ldblprec);
 #endif // defined LMI_X87
     std::cout
         << "  " << i_upper_n_over_n_from_i_T    <long double,12>()(intrate)
-        << "  long double precision, std::expm1 and std::log1p\n"
+        << "  long double prec, std::expm1 and std::log1p\n"
         << "  " << i_upper_n_over_n_from_i_naive<long double,12>()(intrate)
-        << "  long double precision, std::pow\n"
+        << "  long double prec, std::pow\n"
         ;
 #if defined LMI_X87
     fenv_initialize();
     fenv_precision(fe_dblprec);
 #endif // defined LMI_X87
     std::cout
+        << "  " << i_upper_n_over_n_from_i      <double,12>()(intrate)
+        << "  double prec, production template\n"
         << "  " << i_upper_n_over_n_from_i_T    <double,12>()(intrate)
-        << "  double precision, std::expm1 and std::log1p\n"
+        << "  double prec, std::expm1 and std::log1p\n"
         << "  " << i_upper_n_over_n_from_i_naive<double,12>()(intrate)
-        << "  double precision, std::pow\n"
+        << "  double prec, std::pow\n"
         ;
 
     fenv_initialize();
@@ -294,6 +296,7 @@ void assay_speed()
     std::cout << "  long double i365 " << TimeAnAliquot(mete3) << '\n';
     std::cout << "  10^-9 nonstd     " << TimeAnAliquot(mete4) << '\n';
     std::cout << "  10^-9 std        " << TimeAnAliquot(mete5) << '\n';
+    std::cout << std::endl;
 }
 
 template<typename T>
@@ -557,6 +560,8 @@ int test_main(int, char*[])
             )
         );
 
+    std::cout << LMI_CONTEXT << '\n' << std::endl;
+
     assay_speed();
 
     sample_results();