Adding petsc_amg as preconditioner lets code run in parallel.

fenics_mpi_example.py

@@ -8,7 +8,7 @@
 
 import mshr as ms
 import numpy as np
-
+import time
 import random
 from dolfin import *
 # Class representing the intial conditions
@@ -53,7 +53,7 @@ y_mesh = 1
 # mesh = UnitSquareMesh.create(x_mesh, y_mesh, CellType.Type.quadrilateral)
 # mesh = RectangleMesh(Point(0, 0), Point(1, 0.02), x_mesh, y_mesh)
 domain = ms.Sphere(Point(0, 0, 0), 1.0)
-mesh = ms.generate_mesh(domain, 60)
+mesh = ms.generate_mesh(domain, 50)
 P1 = FiniteElement("Lagrange", mesh.ufl_cell(), 1)
 ME = FunctionSpace(mesh, P1*P1)
 # Define trial and test functions
@@ -86,8 +86,10 @@ a = derivative(L, u, du)
 problem = CahnHilliardEquation(a, L)
 solver = NewtonSolver()
 solver.parameters["linear_solver"] = "gmres"
-solver.parameters["preconditioner"] = "ilu"
+#solver.parameters["preconditioner"] = "hypre_euclid"
+solver.parameters["preconditioner"] = "petsc_amg"
 #solver.parameters["linear_solver"] = "mumps"
+#solver.parameters["preconditioner"] = "ilu"
 solver.parameters["convergence_criterion"] = "incremental"
 solver.parameters["relative_tolerance"] = 1e-6
 # Output file
@@ -95,9 +97,11 @@ file = File("output.pvd", "compressed")
 
 # Step in time
 t = 0.0
-T = 3*dt
+T = 2*dt
+ti = time.time()
 while (t < T):
     file << (u.split()[0], t)
     t += dt
     u0.vector()[:] = u.vector()
     solver.solve(problem, u.vector())
+print(time.time()-ti)