def setUp(self):
self.n = 200
self.A = PysparseMatrix(matrix=poisson.poisson2d_sym_blk(self.n))
self.x_exact = numpy.ones(self.n*self.n)/self.n
self.normx = 1.0/self.n
self.b = self.A * self.x_exact
h = 1.0 / self.n
lmbd_min = 4.0/h/h * (math.sin(math.pi*h/2.0) ** 2 +
math.sin(math.pi*h/2.0) ** 2)
lmbd_max = 4.0/h/h * (math.sin((self.n - 1)*math.pi*h/2.0) ** 2 +
math.sin((self.n - 1)*math.pi*h/2.0) ** 2)
cond = lmbd_max/lmbd_min
self.tol = cond * macheps()
self.LU = None
self.relerr = 0.0
self.descr = ''
self.fmt = '\t%10s %8.2e %8.2e %8d %8d %6.2f %6.2f\n'
def setUp(self):
self.n = 20
self.A = poisson.poisson2d(self.n)
self.S = poisson.poisson2d_sym(self.n)
self.B = poisson.poisson2d_sym_blk(self.n)
import math, time
import Numeric
from pysparse import spmatrix, itsolvers, precon, poisson
N = 200
TOL = 1e-8
MAXIT = 800
SSOR_STEPS = 2
L = poisson.poisson2d_sym_blk(N)
S = L.to_sss()
b = Numeric.ones(N*N, 'd')
print 'Solving 2D-Laplace equation using PCG and SSOR preconditioner with variable omega'
print
print 'omega nit time resid'
print '--------------------------------'
for omega in [0.1*(i+1) for i in range(20)]:
K_ssor = precon.ssor(S, omega, SSOR_STEPS)
t1 = time.clock()
x = Numeric.zeros(N*N, 'd')
info, iter, relres = itsolvers.pcg(S, b, x, TOL, MAXIT, K_ssor)
elapsed_time = time.clock() - t1
r = Numeric.zeros(N*N, 'd')
S.matvec(x, r)