From 6feb74641265bfdad22bc6dc36e75dd707445a40 Mon Sep 17 00:00:00 2001
From: Tiago Gomes <tgomes@fc.up.pt>
Date: Tue, 29 May 2012 13:48:08 +0100
Subject: [PATCH] use STL to calculate L1 distance and max norm

---
 packages/CLPBN/horus/Util.cpp | 44 +++++++++++------------------------
 packages/CLPBN/horus/Util.h   | 36 ++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 31 deletions(-)

diff --git a/packages/CLPBN/horus/Util.cpp b/packages/CLPBN/horus/Util.cpp
index 63ef64426..8bb6c933e 100644
--- a/packages/CLPBN/horus/Util.cpp
+++ b/packages/CLPBN/horus/Util.cpp
@@ -321,23 +321,15 @@ namespace LogAware {
 void
 normalize (Params& v)
 {
-  double sum = LogAware::addIdenty();
   if (Globals::logDomain) {
-    for (size_t i = 0; i < v.size(); i++) {
-      sum = Util::logSum (sum, v[i]);
-    }
+    double sum = std::accumulate (v.begin(), v.end(),
+        LogAware::addIdenty(), Util::logSum);
     assert (sum != -numeric_limits<double>::infinity());
-    for (size_t i = 0; i < v.size(); i++) {
-      v[i] -= sum;
-    }
+    v -= sum;
   } else {
-    for (size_t i = 0; i < v.size(); i++) {
-      sum += v[i];
-    }
+    double sum = std::accumulate (v.begin(), v.end(), 0);
     assert (sum != 0.0);
-    for (size_t i = 0; i < v.size(); i++) {
-      v[i] /= sum;
-    }
+    v /= sum;
   }
 }
 
@@ -349,13 +341,11 @@ getL1Distance (const Params& v1, const Params& v2)
   assert (v1.size() == v2.size());
   double dist = 0.0;
   if (Globals::logDomain) {
-    for (size_t i = 0; i < v1.size(); i++) {
-      dist += abs (exp(v1[i]) - exp(v2[i]));
-    }
+    dist = std::inner_product (v1.begin(), v1.end(), v2.begin(), 0.0,
+        std::plus<double>(), FuncObject::abs_diff_exp<double>());
   } else {
-    for (size_t i = 0; i < v1.size(); i++) {
-      dist += abs (v1[i] - v2[i]);
-    }
+    dist = std::inner_product (v1.begin(), v1.end(), v2.begin(), 0.0,
+        std::plus<double>(), FuncObject::abs_diff<double>());
   }
   return dist;
 }
@@ -368,19 +358,11 @@ getMaxNorm (const Params& v1, const Params& v2)
   assert (v1.size() == v2.size());
   double max = 0.0;
   if (Globals::logDomain) {
-    for (size_t i = 0; i < v1.size(); i++) {
-      double diff = abs (exp(v1[i]) - exp(v2[i]));
-      if (diff > max) {
-        max = diff;
-      }
-    }
+    max = std::inner_product (v1.begin(), v1.end(), v2.begin(), 0.0,
+        FuncObject::max<double>(), FuncObject::abs_diff_exp<double>());
   } else {
-    for (size_t i = 0; i < v1.size(); i++) {
-      double diff = abs (v1[i] - v2[i]);
-      if (diff > max) {
-        max = diff;
-      }
-    }
+    max = std::inner_product (v1.begin(), v1.end(), v2.begin(), 0.0,
+        FuncObject::max<double>(), FuncObject::abs_diff<double>());
   }
   return max;
 }
diff --git a/packages/CLPBN/horus/Util.h b/packages/CLPBN/horus/Util.h
index 5925ec908..9d9f39596 100644
--- a/packages/CLPBN/horus/Util.h
+++ b/packages/CLPBN/horus/Util.h
@@ -382,5 +382,41 @@ std::ostream& operator << (std::ostream& os, const vector<T>& v)
   return os;
 }
 
+
+namespace FuncObject {
+
+template<typename T>
+struct max : public std::binary_function<T, T, T>
+{
+  T operator() (const T& x, const T& y) const
+  {
+    return x < y ? y : x;
+  }
+};
+
+
+
+template <typename T>
+struct abs_diff : public std::binary_function<T, T, T>
+{
+  T operator() (const T& x, const T& y) const
+  {
+    return std::abs (x - y);
+  }
+};
+
+
+
+template <typename T>
+struct abs_diff_exp : public std::binary_function<T, T, T>
+{
+  T operator() (const T& x, const T& y) const
+  {
+    return std::abs (std::exp (x) - std::exp (y));
+  }
+};
+
+}
+
 #endif // HORUS_UTIL_H