From 93241e6cc45f4d5173cff7150404c01bfb113c4d Mon Sep 17 00:00:00 2001
From: Daniel Milroy <daniel.milroy@gmail.com>
Date: Fri, 10 Feb 2023 14:33:58 -0800
Subject: [PATCH] policies: replace O(n) accumulate op

---
 resource/policies/dfu_match_multilevel_id.hpp |  6 ++--
 .../policies/dfu_match_multilevel_id_impl.hpp | 29 +++++++------------
 2 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/resource/policies/dfu_match_multilevel_id.hpp b/resource/policies/dfu_match_multilevel_id.hpp
index 7f4611f80..99e694c0e 100644
--- a/resource/policies/dfu_match_multilevel_id.hpp
+++ b/resource/policies/dfu_match_multilevel_id.hpp
@@ -107,7 +107,8 @@ class multilevel_id_t : public dfu_match_cb_t
                         unsigned int add_by,
                         unsigned int multiply_by);
         score_factor_t (const score_factor_t &o) = default;
-        int64_t calc_factor (int64_t base_factor, int64_t break_tie) const;
+        int64_t calc_factor (int64_t base_factor, int64_t break_tie);
+        int64_t m_factor = 0;
 
     private:
         std::string m_type;
@@ -116,11 +117,10 @@ class multilevel_id_t : public dfu_match_cb_t
     };
 
     void set_base_factor (const std::string &type, unsigned int id);
-    int64_t calc_multilevel_scores () const;
 
     FOLD m_comp;
     unsigned m_stop_on_k_matches = 0;
-    std::vector<int64_t> m_multilevel_scores;
+    int64_t m_multilevel_scores = 0;
     std::unordered_map<std::string, score_factor_t> m_multilevel_factors;
 };
 
diff --git a/resource/policies/dfu_match_multilevel_id_impl.hpp b/resource/policies/dfu_match_multilevel_id_impl.hpp
index 97585daa1..b6e369880 100644
--- a/resource/policies/dfu_match_multilevel_id_impl.hpp
+++ b/resource/policies/dfu_match_multilevel_id_impl.hpp
@@ -36,9 +36,9 @@ multilevel_id_t<FOLD>::score_factor_t::score_factor_t (const std::string &type,
 template<typename FOLD>
 int64_t multilevel_id_t<FOLD>::score_factor_t::calc_factor (
                                     int64_t base_factor,
-                                    int64_t break_tie) const
+                                    int64_t break_tie)
 {
-    int64_t add, mul, tie, factor;
+    int64_t add, mul, tie;
     if (base_factor < 0 || break_tie < 0) {
         errno = EINVAL;
         return -1;
@@ -61,15 +61,8 @@ int64_t multilevel_id_t<FOLD>::score_factor_t::calc_factor (
         errno = EOVERFLOW;
         return -1;
     }
-    factor = mul + tie;
-    return factor;
-}
-
-template<typename FOLD>
-int64_t multilevel_id_t<FOLD>::calc_multilevel_scores () const
-{
-    return std::accumulate (m_multilevel_scores.begin (),
-                            m_multilevel_scores.end (), 0);
+    m_factor = mul + tie;
+    return m_factor;
 }
 
 
@@ -138,7 +131,7 @@ int multilevel_id_t<FOLD>::dom_finish_graph (
         dfu.choose_accum_best_k (subsystem, type, count, m_comp);
     }
     dfu.set_overall_score (score);
-    m_multilevel_scores.clear ();
+    m_multilevel_scores = 0;
     return (score == MATCH_MET)? 0 : -1;
 }
 
@@ -168,7 +161,7 @@ int multilevel_id_t<FOLD>::dom_discover_vtx (
         int64_t factor =  f.calc_factor (g[u].id+1, g[u].uniq_id);
         if (factor < 0)
             return factor;
-        m_multilevel_scores.push_back (factor);
+        m_multilevel_scores += factor;
     }
     incr ();
     return 0;
@@ -185,7 +178,6 @@ int multilevel_id_t<FOLD>::dom_finish_vtx (
 {
     int64_t score = MATCH_MET;
     int64_t overall;
-    unsigned prefix;
 
     for (auto &resource : resources) {
         if (resource.type != g[u].type)
@@ -204,11 +196,12 @@ int multilevel_id_t<FOLD>::dom_finish_vtx (
         }
     }
 
-    if (m_multilevel_factors.find (g[u].type) != m_multilevel_factors.end ())
-        m_multilevel_scores.pop_back ();
+    auto it = m_multilevel_factors.find (g[u].type);
+    if (it != m_multilevel_factors.end ())
+        m_multilevel_scores -= it->second.m_factor;
 
-    prefix = calc_multilevel_scores ();
-    overall = (score == MATCH_MET)? (score + prefix + g[u].id + 1) : score;
+    overall = (score == MATCH_MET)? (score + m_multilevel_scores
+                                     + g[u].id + 1) : score;
     dfu.set_overall_score (overall);
     decr ();
     return (score == MATCH_MET)? 0 : -1;