X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/168ca8727e3eb1927743578be07e949bf7a475dd..170f768cfb3e06f5d870854928bc04cfcddcef52:/src/xbt/random.cpp

diff --git a/src/xbt/random.cpp b/src/xbt/random.cpp
index 04aa0fc04e..5621f5a345 100644
--- a/src/xbt/random.cpp
+++ b/src/xbt/random.cpp
@@ -3,57 +3,81 @@
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
-#include "xbt/random.hpp"
 #include "xbt/asserts.h"
+#include <fstream>
+#include <iostream>
 #include <limits>
-#include <random>
+#include <memory>
+#include <string>
+#include <xbt/log.hpp>
+#include <xbt/random.hpp>
+
+XBT_LOG_EXTERNAL_CATEGORY(xbt);
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_random, xbt, "Random");
 
 namespace simgrid {
 namespace xbt {
 namespace random {
-enum xbt_random_implem { XBT_RNG_xbt, XBT_RNG_std };
-static xbt_random_implem rng_implem = XBT_RNG_xbt;
 
-static std::mt19937 mt19937_gen;
+bool Random::read_state(std::string filename)
+{
+  std::ifstream file(filename);
+  file >> mt19937_gen;
+  file.close();
+  if (file.fail())
+    XBT_WARN("Could not save the RNG state to file %s.", filename.c_str());
+  return not file.fail();
+}
 
-void set_implem_xbt()
+bool Random::write_state(std::string filename)
 {
-  rng_implem = XBT_RNG_xbt;
+  std::ofstream file(filename);
+  file << mt19937_gen;
+  file.close();
+  if (file.fail())
+    XBT_WARN("Could not read the RNG state from file %s.", filename.c_str());
+  return not file.fail();
 }
-void set_implem_std()
+
+int StdRandom::uniform_int(int min, int max)
 {
-  rng_implem = XBT_RNG_std;
+  std::uniform_int_distribution<> dist(min, max);
+  return dist(mt19937_gen);
 }
-void set_mersenne_seed(int seed)
+
+double StdRandom::uniform_real(double min, double max)
 {
-  mt19937_gen.seed(seed);
+  std::uniform_real_distribution<> dist(min, max);
+  return dist(mt19937_gen);
 }
 
-int uniform_int(int min, int max)
+double StdRandom::exponential(double lambda)
 {
-  if (rng_implem == XBT_RNG_std) {
-    std::uniform_int_distribution<> dist(min, max);
-    return dist(mt19937_gen);
-  }
+  std::exponential_distribution<> dist(lambda);
+  return dist(mt19937_gen);
+}
 
+double StdRandom::normal(double mean, double sd)
+{
+  std::normal_distribution<> dist(mean, sd);
+  return dist(mt19937_gen);
+}
+
+int XbtRandom::uniform_int(int min, int max)
+{
   unsigned long range  = max - min + 1;
-  unsigned long value  = mt19937_gen();
   xbt_assert(min <= max,
              "The minimum value for the uniform integer distribution must not be greater than the maximum value");
   xbt_assert(range > 0, "Overflow in the uniform integer distribution, please use a smaller range.");
-  while (value >= decltype(mt19937_gen)::max() - decltype(mt19937_gen)::max() % range) {
+  unsigned long value;
+  do {
     value = mt19937_gen();
-  }
+  } while (value >= decltype(mt19937_gen)::max() - decltype(mt19937_gen)::max() % range);
   return value % range + min;
 }
 
-double uniform_real(double min, double max)
+double XbtRandom::uniform_real(double min, double max)
 {
-  if (rng_implem == XBT_RNG_std) {
-    std::uniform_real_distribution<> dist(min, max);
-    return dist(mt19937_gen);
-  }
-
   // This reuses Boost's uniform real distribution ideas
   constexpr unsigned long divisor = decltype(mt19937_gen)::max() - decltype(mt19937_gen)::min();
   unsigned long numerator;
@@ -63,32 +87,68 @@ double uniform_real(double min, double max)
   return min + (max - min) * numerator / divisor;
 }
 
-double exponential(double lambda)
+double XbtRandom::exponential(double lambda)
 {
-  if (rng_implem == XBT_RNG_std) {
-    std::exponential_distribution<> dist(lambda);
-    return dist(mt19937_gen);
-  }
-
   return -1.0 / lambda * log(uniform_real(0.0, 1.0));
 }
 
-double normal(double mean, double sd)
+double XbtRandom::normal(double mean, double sd)
 {
-  if (rng_implem == XBT_RNG_std) {
-    std::normal_distribution<> dist(mean, sd);
-    return dist(mt19937_gen);
-  }
-
-  double u1 = 0.0;
-  while (u1 < std::numeric_limits<double>::min()) {
+  double u1;
+  do {
     u1 = uniform_real(0.0, 1.0);
-  }
+  } while (u1 < std::numeric_limits<double>::min());
   double u2 = uniform_real(0.0, 1.0);
   double z0 = sqrt(-2.0 * log(u1)) * cos(2.0 * M_PI * u2);
   return z0 * sd + mean;
 }
 
+static std::unique_ptr<Random> default_random(new XbtRandom);
+
+void set_implem_xbt()
+{
+  default_random.reset(new XbtRandom);
+}
+void set_implem_std()
+{
+  default_random.reset(new StdRandom);
+}
+
+void set_mersenne_seed(int seed)
+{
+  default_random->set_seed(seed);
+}
+
+bool read_mersenne_state(std::string filename)
+{
+  return default_random->read_state(filename);
+}
+
+bool write_mersenne_state(std::string filename)
+{
+  return default_random->write_state(filename);
+}
+
+int uniform_int(int min, int max)
+{
+  return default_random->uniform_int(min, max);
+}
+
+double uniform_real(double min, double max)
+{
+  return default_random->uniform_real(min, max);
+}
+
+double exponential(double lambda)
+{
+  return default_random->exponential(lambda);
+}
+
+double normal(double mean, double sd)
+{
+  return default_random->normal(mean, sd);
+}
+
 } // namespace random
 } // namespace xbt
 } // namespace simgrid