From 026885a8a65139a40ffaa1624f7d2098f8941c59 Mon Sep 17 00:00:00 2001
From: Jeremy Fix <jeremy.fix@centralesupelec.fr>
Date: Sat, 29 Sep 2018 08:47:24 +0200
Subject: [PATCH] a bug in rl softmax...forgot to use the values for
 discrete_distribution

---
 examples/example-000-003-agents.cc | 27 +++++++++++++++++++++++++++
 src/rlAlgo.hpp                     | 11 +++++------
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/examples/example-000-003-agents.cc b/examples/example-000-003-agents.cc
index 6bcd0fc..e07bf27 100644
--- a/examples/example-000-003-agents.cc
+++ b/examples/example-000-003-agents.cc
@@ -70,6 +70,32 @@ class Q {
 
 // Let us define functions for plotting histograms
 
+template<typename QFUNCTION,
+    typename ACTION_ITERATOR>
+    void plotQ(std::string title, const QFUNCTION q_function, 
+            const ACTION_ITERATOR& a_begin, 
+            const ACTION_ITERATOR& a_end,
+            std::string filename) {
+        std::ofstream file;
+
+        file.open(filename.c_str());
+        if(!file) {
+            std::cerr << "Cannot open \"" << filename << "\". Aborting";
+            return;
+        }
+        file << "set title '" << title << "';" << std::endl
+            << "set xrange [0:" << NB_ARMS-1 << "];" << std::endl
+            << "set yrange [0:1];" << std::endl
+            << "set xlabel 'Actions'" << std::endl
+            << "plot '-' with lines notitle" << std::endl;
+        S dummy;
+        for(auto ait = a_begin; ait != a_end ; ++ait)
+            file << *ait << ' ' << q_function(dummy, *ait) << std::endl;
+
+        file.close();
+        std::cout << "\"" << filename << "\" generated." << std::endl;
+    };
+
 #define HISTO_NB_SAMPLES 20000
 
 template<typename POLICY>
@@ -176,6 +202,7 @@ int main(int argc, char* argv[]) {
             x = a/(double)NB_ARMS;
             q.tabular_values[a] = (1-.2*x)*pow(sin(5*(x+.15)),2);
         }
+        plotQ("Q values", q, a_begin, a_end, "Qvalues.plot");
 
         // Let us plot histograms of policys.
         plot1D("Random policy choices",random_policy,"RandomPolicy.plot");
diff --git a/src/rlAlgo.hpp b/src/rlAlgo.hpp
index e1a3668..6efb85f 100644
--- a/src/rlAlgo.hpp
+++ b/src/rlAlgo.hpp
@@ -190,12 +190,12 @@ namespace rl {
                     RANDOM_DEVICE& rd) 
             -> decltype(*begin) {
                 auto size = end-begin;
-                std::vector<double> cum(size);
+                std::vector<double> fvalues(size);
                 auto iter = begin;
-                auto citer = cum.begin();
-                for(; iter != end; ++iter, ++citer)
-                    *citer = f(*iter);
-                std::discrete_distribution<decltype(end - begin)> d;
+                auto fvaluesiter = fvalues.begin();
+                for(; iter != end; ++iter, ++fvaluesiter)
+                    *fvaluesiter = f(*iter);
+                std::discrete_distribution<decltype(end - begin)> d(fvalues.begin(), fvalues.end());
                 return *(begin + d(rd));
 
             }
@@ -220,7 +220,6 @@ namespace rl {
               fmax = std::max(fmax, f_values[*it]);
           }
 
-
           auto shifted_exp_values = [&temperature, &f_values, &fmax](const decltype(*begin)& a) -> double {
             return exp((f_values[a] - fmax)/temperature);
           };