[lmi-commits] [lmi] master 762056e 05/14: Prefer PETE's operator<<=() to assign()

[Greg Chicares]

branch: master
commit 762056ec6c0596ab3ce90926c7fb3cc3af029efd
Author: Gregory W. Chicares <gchicares@sbcglobal.net>
Commit: Gregory W. Chicares <gchicares@sbcglobal.net>

    Prefer PETE's operator<<=() to assign()
    
    Replaced assign() and the awful
      std::vector<double> y(x.size());
      x += y;
    anti-idiom with operator<<=(), which, despite its ugliness, is less bad.
    
    This change does make mete_reserve() slower, by about ten percent for
    x86_64-pc-linux-gnu and a hundred percent for i686-w64-mingw32, but
    that's okay because the penalty is due to heap allocation. Assigning
    PETE expressions to a vector that already has the right size is faster
    than replacing the vector, but that's a PETE matter for separate
    investigation. Here, the goal is to write complex code clearly. The
    reserve calculation is apparently so fast that allocating a new vector
    on the heap is not vanishingly cheap in comparison. The slowness of
    small heap allocations for i686 on 'wine' is the tail that mustn't be
    allowed to wag the dog.
---
 commutation_functions_test.cpp | 49 +++++++++++++++++++++---------------------
 1 file changed, 25 insertions(+), 24 deletions(-)

diff --git a/commutation_functions_test.cpp b/commutation_functions_test.cpp
index 573f7b0..fc2ed62 100644
--- a/commutation_functions_test.cpp
+++ b/commutation_functions_test.cpp
@@ -84,8 +84,8 @@ void mete_reserve
     for(int j = 0; j < 100; ++j)
         {
         volatile double premium = (10.0 * ulcf.aDomega() + ulcf.kM()[0]) / 
ulcf.aN()[0];
-        assign(reserve, premium * ulcf.aD() - ulcf.kC());
-        assign(reserve, fwd_sum(reserve) / ulcf.EaD());
+        reserve <<= premium * ulcf.aD() - ulcf.kC();
+        reserve <<= fwd_sum(reserve) / ulcf.EaD();
         }
 }
 
@@ -160,18 +160,18 @@ void TestEckleyTable2()
 
     ULCommFns CF(coi, ic, ig, mce_option1_for_7702, mce_annual);
 
-    std::vector<double> nsp    (coi.size());
-    nsp     += (CF.aDomega() + CF.kM()) / CF.aD();
+    std::vector<double> nsp;
+    nsp     <<= (CF.aDomega() + CF.kM()) / CF.aD();
 
-    std::vector<double> annuity(coi.size());
-    annuity += (               CF.aN()) / CF.aD();
+    std::vector<double> annuity;
+    annuity <<= (               CF.aN()) / CF.aD();
 
-    std::vector<double> premium(coi.size());
-    premium += (CF.aDomega() + CF.kM()) / CF.aN();
+    std::vector<double> premium;
+    premium <<= (CF.aDomega() + CF.kM()) / CF.aN();
 
-    std::vector<double> reserve(coi.size());
-    reserve += premium[0] * CF.aD() - CF.kC();
-    assign(reserve, fwd_sum(reserve) / CF.EaD());
+    std::vector<double> reserve;
+    reserve <<= premium[0] * CF.aD() - CF.kC();
+    reserve <<= fwd_sum(reserve) / CF.EaD();
 
     {
     double tolerance = 0.0000005;
@@ -287,12 +287,12 @@ void TestEckleyTables3and4()
 
     ULCommFns CF(coi, ic, ig, mce_option2_for_7702, mce_annual);
 
-    std::vector<double> premium(coi.size());
-    premium += (2.0 * CF.aDomega() + CF.kM()) / CF.aN();
+    std::vector<double> premium;
+    premium <<= (2.0 * CF.aDomega() + CF.kM()) / CF.aN();
 
-    std::vector<double> reserve(coi.size());
-    reserve += premium[0] * CF.aD() - CF.kC();
-    assign(reserve, fwd_sum(reserve) / CF.EaD());
+    std::vector<double> reserve;
+    reserve <<= premium[0] * CF.aD() - CF.kC();
+    reserve <<= fwd_sum(reserve) / CF.EaD();
 
     double tolerance = 0.000005;
     double worst_discrepancy = 0.0;
@@ -518,8 +518,8 @@ void Test_1954_1958_IET_3pct()
     std::vector<double> E_ell_ex(ell_ex);
     E_ell_ex.erase(E_ell_ex.begin());
     E_ell_ex.push_back(0.0);
-    std::vector<double> q(ell_ex.size());
-    q += (ell_ex - E_ell_ex) / ell_ex;
+    std::vector<double> q;
+    q <<= (ell_ex - E_ell_ex) / ell_ex;
 
     std::vector<double> i(q.size(), 0.03);
 
@@ -632,7 +632,7 @@ void Test_1980_CSO_Male_ANB()
         };
 
     std::vector<double> q(sample_q());
-    assign(q, apply_binary(coi_rate_from_q<double>(), q, 1.0 / 11.0));
+    q <<= apply_binary(coi_rate_from_q<double>(), q, 1.0 / 11.0);
 
     std::vector<double>ic(q.size(), i_upper_12_over_12_from_i<double>()(0.07));
     std::vector<double>ig(q.size(), i_upper_12_over_12_from_i<double>()(0.03));
@@ -640,9 +640,9 @@ void Test_1980_CSO_Male_ANB()
     ULCommFns ulcf(q, ic, ig, mce_option2_for_7702, mce_monthly);
 
     double premium = (10.0 * ulcf.aDomega() + ulcf.kM()[0]) / ulcf.aN()[0];
-    std::vector<double> reserve(q.size());
-    assign(reserve, premium * ulcf.aD() - ulcf.kC());
-    assign(reserve, fwd_sum(reserve) / ulcf.EaD());
+    std::vector<double> reserve;
+    reserve <<= premium * ulcf.aD() - ulcf.kC();
+    reserve <<= fwd_sum(reserve) / ulcf.EaD();
 
     double tolerance = 1.0e-13;
     double worst_discrepancy = 0.0;
@@ -678,14 +678,15 @@ void Test_1980_CSO_Male_ANB()
 void assay_speed()
 {
     std::vector<double> q(sample_q());
-    assign(q, apply_binary(coi_rate_from_q<double>(), q, 1.0 / 11.0));
+    q <<= apply_binary(coi_rate_from_q<double>(), q, 1.0 / 11.0);
 
     std::vector<double>ic(q.size(), i_upper_12_over_12_from_i<double>()(0.07));
     std::vector<double>ig(q.size(), i_upper_12_over_12_from_i<double>()(0.03));
 
     ULCommFns ulcf(q, ic, ig, mce_option2_for_7702, mce_monthly);
 
-    std::vector<double> reserve(q.size());
+    std::vector<double> reserve;
+    reserve.reserve(q.size());
 
     auto f0 = [&q, &ic]         {mete_olcf(q, ic);};
     auto f1 = [&q, &ic, ig]     {mete_ulcf(q, ic, ig);};