[PPL-devel] [GIT] ppl/ppl(sparse_matrices): MIP_Problem: optimize find_create() calls in linear_combine() (#2).

[Marco Poletti]

Module: ppl/ppl
Branch: sparse_matrices
Commit: d117160799a3174cd12c8d24a7d8ba378569f17b
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=d117160799a3174cd12c8d24a7d8ba378569f17b

Author: Marco Poletti <poletti.marco at gmail.com>
Date:   Mon Mar 22 13:32:36 2010 +0100

MIP_Problem: optimize find_create() calls in linear_combine() (#2).

---

 src/MIP_Problem.cc |   33 ++++++++++++---------------------
 1 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/src/MIP_Problem.cc b/src/MIP_Problem.cc
index 95ef74a..7b42739 100644
--- a/src/MIP_Problem.cc
+++ b/src/MIP_Problem.cc
@@ -1333,13 +1333,10 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x,
   while ((i != i_end) && (j != j_end)) {
     if (j->first < i->first) {
       if (j->first != k) {
-        // FIXME: check if adding "if (j->second != 0)" speeds this up.
-        itr = x.find_create(j->first);
+        // The following statements are equivalent to
+        // sub_mul_assign(x[j->first], j->second, normalized_row_k);
+        itr = x.find_create(*j);
         Coefficient& x_i = (*itr).second;
-        PPL_ASSERT(x_i == 0);
-
-        // sub_mul_assign(x_i, j->second, normalized_row_k);
-        x_i = j->second;
         x_i *= normalized_row_k;
         neg_assign(x_i);
 
@@ -1369,12 +1366,10 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x,
   while ((i != i_end) && (j != j_end)) {
     if (j->first < i->first) {
       if (j->first != k) {
-        // FIXME: check if adding "if (j->second != 0)" speeds this up.
-        itr = x.find_create(j->first, itr);
+        // The following statements are equivalent to
+        // sub_mul_assign(x[j->first], j->second, normalized_row_k);
+        itr = x.find_create(*j,itr);
         Coefficient& x_i = (*itr).second;
-        PPL_ASSERT(x_i == 0);
-        // sub_mul_assign(x_i, j->second, normalized_row_k);
-        x_i = j->second;
         x_i *= normalized_row_k;
         neg_assign(x_i);
       }
@@ -1420,12 +1415,10 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x,
   if (itr == x.end()) {
     while (j != j_end) {
       if (j->first != k) {
-        // FIXME: check if adding "if (j->second != 0)" speeds this up.
-        itr = x.find_create(j->first);
+        // The following statements are equivalent to
+        // sub_mul_assign(x[j->first], j->second, normalized_row_k);
+        itr = x.find_create(*j);
         Coefficient& x_i = (*itr).second;
-        PPL_ASSERT(x_i == 0);
-        // sub_mul_assign(x_i, j->second, normalized_row_k);
-        x_i = j->second;
         x_i *= normalized_row_k;
         neg_assign(x_i);
 
@@ -1439,12 +1432,10 @@ PPL::MIP_Problem::linear_combine(matrix_row_reference_type x,
   }
   while (j != j_end) {
     if (j->first != k) {
-      // FIXME: check if adding "if (j->second != 0)" speeds this up.
-      itr = x.find_create(j->first,itr);
+      // The following statements are equivalent to
+      // sub_mul_assign(x[j->first], j->second, normalized_row_k);
+      itr = x.find_create(*j);
       Coefficient& x_i = (*itr).second;
-      PPL_ASSERT(x_i == 0);
-      // sub_mul_assign(x_i, j->second, normalized_row_k);
-      x_i = j->second;
       x_i *= normalized_row_k;
       neg_assign(x_i);
     }