Changeset 2055 for inundation/parallel/pmesh_divide.py

Timestamp:

Nov 24, 2005, 10:21:05 AM (19 years ago)

Author:

jack

Message:

Added pmesh_divide_metis to pmesh_divide.py. Note that the arguments have changed, but the return stays the same.

Run_parallel_sw_merimbula_metis.py is the same as run_parallel_sw_merimbula, except it uses pymetis to partition the grid.

File:

• inundation/parallel/pmesh_divide.py (modified) (5 diffs)

inundation/parallel/pmesh_divide.py

@@ -20 +20 @@
 
 from math import floor
-from Numeric import zeros, Float, Int
+from Numeric import zeros, Float, Int, reshape
 
 #########################################################
@@ -151 +151 @@
         for i in range(N):
             q_reord[k][index[i]]=quantities[k].vertex_values[i]
-
     del index
 
@@ -268 +267 @@
     tri_index = {}
     N = domain.number_of_elements
-
+ 
     #sort by x coordinate of centroid
     from Numeric import argsort
@@ -286 +285 @@
 
     #print tri_list
-
     #print tri_index
 
@@ -321 +319 @@
 
     return nodes, triangles, boundary, triangles_per_proc, quantities
+
+
+from os import sep
+from sys import path
+
+path.append('..' + sep + 'pymetis')
+
+from metis import partMeshNodal
+
+def pmesh_divide_metis(domain, n_procs):
+    # initialise the lists
+    triangles_per_proc = []
+    tri_list = []
+    proc_sum = []
+    for i in range(n_procs):
+        tri_list.append([])
+        triangles_per_proc.append(0)
+        proc_sum.append([])
+
+    # Prepare variables for the metis call
+    n_tri = len(domain.triangles)
+    n_vert = len(domain.coordinates)
+    t_list = domain.triangles.copy()
+    t_list = reshape(t_list, (-1,))
+
+    # The 1 here is for triangular mesh elements.
+    edgecut, epart, npart = partMeshNodal(n_tri, n_vert, t_list, 1, n_procs)
+
+    # print edgecut
+    # print epart
+    # print npart
+
+    del edgecut
+    del npart
+
+    # Assign triangles to processes, according to what metis told us.
+    
+    tri_index = {}
+    triangles = []        
+    for i in range(n_tri):
+        triangles_per_proc[epart[i]] = triangles_per_proc[epart[i]] + 1
+        tri_list[epart[i]].append(domain.triangles[i])
+        tri_index[i] = ([epart[i], len(tri_list[epart[i]]) - 1])
+
+    # print tri_list
+    # print triangles_per_proc
+
+    # order the triangle list so that all of the triangles belonging
+    # to processor i are listed before those belonging to processor
+    # i+1
+
+    for i in range(n_procs):
+        for t in tri_list[i]:
+            triangles.append(t)
+            
+    # the boundary labels have to changed in accoradance with the
+    # new triangle ordering, proc_sum and tri_index help with this
+
+    proc_sum[0] = 0
+    for i in range(n_procs - 1):
+        proc_sum[i+1]=proc_sum[i]+triangles_per_proc[i]
+
+    # relabel the boundary elements to fit in with the new triangle
+    # ordering
+
+    boundary = {}
+    for b in domain.boundary:
+        t =  tri_index[b[0]]
+        boundary[proc_sum[t[0]]+t[1], b[1]] = domain.boundary[b]
+
+    quantities = reorder(domain.quantities, tri_index, proc_sum)
+
+    # extract the node list
+    nodes = domain.coordinates.copy()
+
+    return nodes, triangles, boundary, triangles_per_proc, quantities