From: Martin Quinson <martin.quinson@ens-rennes.fr>
Date: Wed, 20 Nov 2019 13:09:40 +0000 (+0100)
Subject: rnd: cosmetics to ease the implem
X-Git-Tag: v3.25~377
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/647a6e65f7e55174c44e2fe40576a86bb8fb738c

rnd: cosmetics to ease the implem
---

diff --git a/include/xbt/random.hpp b/include/xbt/random.hpp
index 12a9fe9b7c..b1d8b1461a 100644
--- a/include/xbt/random.hpp
+++ b/include/xbt/random.hpp
@@ -6,24 +6,18 @@
 #ifndef SIMGRID_XBT_RANDOM_HPP
 #define SIMGRID_XBT_RANDOM_HPP
 
-#include <random>
-
 namespace simgrid {
 namespace xbt {
 namespace random {
-enum xbt_random_method { XBT_RNG_xbt, XBT_RNG_std };
 
-void use_xbt();
-void use_std();
+void set_implem_xbt();
+void set_implem_std();
+void set_mersenne_seed(int);
+
 int uniform_int(int, int);
-int xbt_uniform_int(int, int);
 double uniform_real(double, double);
-double xbt_uniform_real(double, double);
 double exponential(double);
-double xbt_exponential(double);
 double normal(double, double);
-double xbt_normal(double, double);
-void set_mersenne_seed(int);
 } // namespace random
 } // namespace xbt
 } // namespace simgrid
diff --git a/src/xbt/random.cpp b/src/xbt/random.cpp
index 07a3ab1b5c..e7ba9e28b5 100644
--- a/src/xbt/random.cpp
+++ b/src/xbt/random.cpp
@@ -11,34 +11,31 @@
 namespace simgrid {
 namespace xbt {
 namespace random {
-std::mt19937 mt19937_gen;
-xbt_random_method current_rng = XBT_RNG_xbt;
+enum xbt_random_implem { XBT_RNG_xbt, XBT_RNG_std };
+static xbt_random_implem rng_implem = XBT_RNG_xbt;
 
-void use_xbt()
+static std::mt19937 mt19937_gen;
+
+void set_implem_xbt()
+{
+  rng_implem = XBT_RNG_xbt;
+}
+void set_implem_std()
 {
-  current_rng = XBT_RNG_xbt;
+  rng_implem = XBT_RNG_std;
 }
-void use_std()
+void set_mersenne_seed(int seed)
 {
-  current_rng = XBT_RNG_std;
+  mt19937_gen.seed(seed);
 }
 
 int uniform_int(int min, int max)
 {
-  switch (current_rng) {
-    case XBT_RNG_xbt:
-      return xbt_uniform_int(min, max);
-    case XBT_RNG_std: {
-      std::uniform_int_distribution<> dist(min, max);
-      return dist(mt19937_gen);
+  if (rng_implem == XBT_RNG_std) {
+    std::uniform_int_distribution<> dist(min, max);
+    return dist(mt19937_gen);
     }
-    default:
-      xbt_assert(false, "The uniform integer distribution is not yet supported for the current RNG.");
-  }
-}
 
-int xbt_uniform_int(int min, int max)
-{
   unsigned long range  = max - min + 1;
   unsigned long value  = mt19937_gen();
   xbt_assert(range > 0, "Overflow in the uniform integer distribution, please use a smaller range.");
@@ -50,20 +47,11 @@ int xbt_uniform_int(int min, int max)
 
 double uniform_real(double min, double max)
 {
-  switch (current_rng) {
-    case XBT_RNG_xbt:
-      return xbt_uniform_real(min, max);
-    case XBT_RNG_std: {
-      std::uniform_real_distribution<> dist(min, max);
-      return dist(mt19937_gen);
+  if (rng_implem == XBT_RNG_std) {
+    std::uniform_real_distribution<> dist(min, max);
+    return dist(mt19937_gen);
     }
-    default:
-      xbt_assert(false, "The uniform real distribution is not yet supported for the current RNG.");
-  }
-}
 
-double xbt_uniform_real(double min, double max)
-{
   // This reuses Boost's uniform real distribution ideas
   unsigned long numerator = mt19937_gen() - mt19937_gen.min();
   unsigned long divisor   = mt19937_gen.max() - mt19937_gen.min();
@@ -72,39 +60,21 @@ double xbt_uniform_real(double min, double max)
 
 double exponential(double lambda)
 {
-  switch (current_rng) {
-    case XBT_RNG_xbt:
-      return xbt_exponential(lambda);
-    case XBT_RNG_std: {
-      std::exponential_distribution<> dist(lambda);
-      return dist(mt19937_gen);
+  if (rng_implem == XBT_RNG_std) {
+    std::exponential_distribution<> dist(lambda);
+    return dist(mt19937_gen);
     }
-    default:
-      xbt_assert(false, "The exponential distribution is not yet supported for the current RNG.");
-  }
-}
 
-double xbt_exponential(double lambda)
-{
   return -1 / lambda * log(uniform_real(0, 1));
 }
 
 double normal(double mean, double sd)
 {
-  switch (current_rng) {
-    case XBT_RNG_xbt:
-      return xbt_normal(mean, sd);
-    case XBT_RNG_std: {
-      std::normal_distribution<> dist(mean, sd);
-      return dist(mt19937_gen);
-    }
-    default:
-      xbt_assert(false, "The normal distribution is not yet supported for the curent RNG.");
+  if (rng_implem == XBT_RNG_std) {
+    std::normal_distribution<> dist(mean, sd);
+    return dist(mt19937_gen);
   }
-}
 
-double xbt_normal(double mean, double sd)
-{
   double u1 = 0;
   while (u1 < std::numeric_limits<double>::min()) {
     u1 = uniform_real(0, 1);
@@ -114,11 +84,6 @@ double xbt_normal(double mean, double sd)
   return z0 * sd + mean;
 }
 
-void set_mersenne_seed(int seed)
-{
-  mt19937_gen.seed(seed);
-}
-
 } // namespace random
 } // namespace xbt
 } // namespace simgrid
diff --git a/src/xbt/random_test.cpp b/src/xbt/random_test.cpp
index 01ae026be7..d8cee2232a 100644
--- a/src/xbt/random_test.cpp
+++ b/src/xbt/random_test.cpp
@@ -26,7 +26,7 @@ TEST_CASE("xbt::random: Random Number Generation")
     gen.seed(12345);
 
     simgrid::xbt::random::set_mersenne_seed(12345);
-    simgrid::xbt::random::use_std();
+    simgrid::xbt::random::set_implem_std();
 
     std::exponential_distribution<> distA(25);
     std::uniform_int_distribution<> distB(1, 6);