From 5851cba291d6ac7b89baf771e4a3821cc1aaa81c Mon Sep 17 00:00:00 2001
From: Arnaud Giersch <arnaud.giersch@iut-bm.univ-fcomte.fr>
Date: Thu, 16 Dec 2010 15:36:33 +0100
Subject: [PATCH 1/1] Add torus topology.

---
 deployment.cpp | 66 +++++++++++++++++++++++++++++++++++++++++++++++---
 deployment.h   |  2 +-
 options.cpp    |  2 +-
 3 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/deployment.cpp b/deployment.cpp
index c5a1f9d..d582dc6 100644
--- a/deployment.cpp
+++ b/deployment.cpp
@@ -122,6 +122,66 @@ void deployment_star::generate()
         set_link(0, i);
 }
 
-// void deployment_torus::generate()
-// {
-// }
+void deployment_torus::generate()
+{
+    unsigned a = 0;
+    unsigned b = size();
+    while (a + 1 < b) {
+        unsigned c = (a + b) / 2;
+        if (c * c < size())
+            a = c;
+        else
+            b = c;
+    }
+    unsigned width = b;
+
+    unsigned first_on_last_line = (size() - 1) - (size() - 1) % width;
+    DEBUG4("torus size = %u ; width = %u ; height = %u ; foll = %u",
+           (unsigned )size(), width,
+           (unsigned )(size() / width + !!(size() % width)),
+           first_on_last_line);
+    for (unsigned i = 0; i < size(); i++) {
+        unsigned next_line;
+        unsigned prev_line;
+        unsigned next_column;
+        unsigned prev_column;
+
+        next_line = i + width;
+        if (next_line >= size())
+            next_line %= width; // rewind
+
+        if (i >= width) {
+            prev_line = i - width;
+        } else {
+            prev_line = first_on_last_line + i; // rewind
+            if (prev_line >= size())
+                prev_line -= width; // need to go at last but one line
+        }
+
+        if (i != size() - 1) {
+            next_column = i + 1;
+            if (next_column % width == 0)
+                next_column -= width; // rewind
+        } else {
+            next_column = first_on_last_line; // special case for last cell
+        }
+
+        if (i % width != 0) {
+            prev_column = i - 1;
+        } else if (i < first_on_last_line) {
+            prev_column = i + width - 1; // rewind
+        } else {
+            prev_column = size() - 1; // special case for 1st cell of last line
+        }
+        if (next_line != i) {
+            set_neighbor(i, next_line);
+            if (prev_line != next_line)
+                set_neighbor(i, prev_line);
+        }
+        if (next_column != i) {
+            set_neighbor(i, next_column);
+            if (prev_column != next_column)
+                set_neighbor(i, prev_column);
+        }
+    }
+}
diff --git a/deployment.h b/deployment.h
index 2009b36..cba191b 100644
--- a/deployment.h
+++ b/deployment.h
@@ -37,7 +37,7 @@ DEPLOYMENT(hcube);
 DEPLOYMENT(line);
 DEPLOYMENT(ring);
 DEPLOYMENT(star);
-// DEPLOYMENT(torus);
+DEPLOYMENT(torus);
 
 #undef DEPLOYMENT
 
diff --git a/options.cpp b/options.cpp
index 1b12ce7..668aed3 100644
--- a/options.cpp
+++ b/options.cpp
@@ -61,7 +61,7 @@ namespace opt {
         NOL_INSERT("ring", "ring topology", deployment_ring);
         NOL_INSERT("star", "star topology, initial load at center",
                    deployment_star);
-        // NOL_INSERT("torus", "torus topology", deployment_torus);
+        NOL_INSERT("torus", "torus topology", deployment_torus);
     }
 
 } // namespace opt
-- 
2.39.5