Changed comment in header

src/parallel/decompositionMethods/scotchDecomp/scotchDecomp.C

@@ -22,40 +22,87 @@ License
     along with OpenFOAM; if not, write to the Free Software Foundation,
     Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 
-    Default strategy:
+    From scotch forum:
-        Strat=b
+ 	
-        {
+    By: Francois PELLEGRINI RE: Graph mapping 'strategy' string [ reply ]  
-            job=t,
+    2008-08-22 10:09 Strategy handling in Scotch is a bit tricky. In order
-            map=t,
+    not to be confused, you must have a clear view of how they are built.
-            poli=S,
+    Here are some rules:
-            sep=
+
-            (
+    1- Strategies are made up of "methods" which are combined by means of
-                m
+    "operators".
+
+    2- A method is of the form "m{param=value,param=value,...}", where "m"
+    is a single character (this is your first error: "f" is a method name,
+    not a parameter name).
+
+    3- There exist different sort of strategies : bipartitioning strategies,
+    mapping strategies, ordering strategies, which cannot be mixed. For
+    instance, you cannot build a bipartitioning strategy and feed it to a
+    mapping method (this is your second error).
+
+    To use the "mapCompute" routine, you must create a mapping strategy, not
+    a bipartitioning one, and so use stratGraphMap() and not
+    stratGraphBipart(). Your mapping strategy should however be based on the
+    "recursive bipartitioning" method ("b"). For instance, a simple (and
+    hence not very efficient) mapping strategy can be :
+
+    "b{sep=f}"
+
+    which computes mappings with the recursive bipartitioning method "b",
+    this latter using the Fiduccia-Mattheyses method "f" to compute its
+    separators.
+
+    If you want an exact partition (see your previous post), try
+    "b{sep=fx}".
+
+    However, these strategies are not the most efficient, as they do not
+    make use of the multi-level framework.
+
+    To use the multi-level framework, try for instance:
+
+    "b{sep=m{vert=100,low=h,asc=f}x}"
+
+    The current default mapping strategy in Scotch can be seen by using the
+    "-vs" option of program gmap. It is, to date:
+
+    b
+    {
+        job=t,
+        map=t,
+        poli=S,
+        sep=
+        (
+            m
+            {
+                asc=b
                 {
-                    asc=b
+                    bnd=d{pass=40,dif=1,rem=1}f{move=80,pass=-1,bal=0.005},
-                    {
+                    org=f{move=80,pass=-1,bal=0.005},
-                        bnd=d{pass=40,dif=1,rem=1}f{move=80,pass=-1,bal=0.005},
+                    width=3
-                        org=f{move=80,pass=-1,bal=0.005},width=3
+                },
-                    },
+                low=h{pass=10}f{move=80,pass=-1,bal=0.0005},
-                    low=h{pass=10}f{move=80,pass=-1,bal=0.0005},
+                type=h,
-                    type=h,
+                vert=80,
-                    vert=80,
+                rat=0.8
-                    rat=0.8
+            }
-                }
+          | m
-              | m
+            {
+                asc=b
                 {
-                    asc=b
+                    bnd=d{pass=40,dif=1,rem=1}f{move=80,pass=-1,bal=0.005},
-                    {
+                    org=f{move=80,pass=-1,bal=0.005},
-                        bnd=d{pass=40,dif=1,rem=1}f{move=80,pass=-1,bal=0.005},
+                    width=3
-                        org=f{move=80,pass=-1,bal=0.005},
+                },
-                        width=3},
+                low=h{pass=10}f{move=80,pass=-1,bal=0.0005},
-                        low=h{pass=10}f{move=80,pass=-1,bal=0.0005},
+                type=h,
-                        type=h,
+                vert=80,
-                        vert=80,
+                rat=0.8
-                        rat=0.8
+            }
-                }
+        )
-            )
+    }
-        }
+
+
 \*---------------------------------------------------------------------------*/
 
 #include "scotchDecomp.H"