From: Jean-Baptiste Hervé <jean-baptiste.herve@esial.net>
Date: Mon, 30 Jul 2012 13:01:48 +0000 (+0200)
Subject: Platform generation : add the exponential topology
X-Git-Tag: v3_8~252
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/ba1b3b30426f7eaff5414547452306c7c47b6168

Platform generation : add the exponential topology
---

diff --git a/include/simgrid/platf_generator.h b/include/simgrid/platf_generator.h
index c5f6d87841..c831252739 100644
--- a/include/simgrid/platf_generator.h
+++ b/include/simgrid/platf_generator.h
@@ -28,6 +28,7 @@ XBT_PUBLIC(void) platf_graph_interconnect_line(void);
 XBT_PUBLIC(void) platf_graph_interconnect_ring(void);
 XBT_PUBLIC(void) platf_graph_interconnect_clique(void);
 XBT_PUBLIC(void) platf_graph_interconnect_uniform(double alpha);
+XBT_PUBLIC(void) platf_graph_interconnect_exponential(double alpha);
 
 // WARNING : Only for debbugging ; should be removed when platform
 // generation works correctly
diff --git a/src/surf/platf_generator.c b/src/surf/platf_generator.c
index 9fa2ec06b5..9d890918fc 100644
--- a/src/surf/platf_generator.c
+++ b/src/surf/platf_generator.c
@@ -200,6 +200,27 @@ void platf_graph_interconnect_uniform(double alpha) {
   }
 }
 
+void platf_graph_interconnect_exponential(double alpha) {
+  /* Create a topology where the probability follows an exponential law
+     Number of edges increases with alpha */
+  xbt_dynar_t dynar_nodes = NULL;
+  xbt_node_t first_node = NULL;
+  xbt_node_t second_node = NULL;
+  unsigned int i,j;
+  double L = sqrt(2.0); /*  L = c*sqrt(2); c=side of placement square */
+  dynar_nodes = xbt_graph_get_nodes(platform_graph);
+  xbt_dynar_foreach(dynar_nodes, i, first_node) {
+    xbt_dynar_foreach(dynar_nodes, j, second_node) {
+      if(j>=i)
+        break;
+      double d = platf_node_distance(first_node, second_node);
+      if(RngStream_RandU01(rng_stream) < alpha*exp(-d/(L-d))) {
+        platf_node_connect(first_node, second_node);
+      }
+    }
+  }
+}
+
 /* Functions used to generate interesting random values */
 
 double random_pareto(double min, double max, double K, double P, double ALPHA) {