def reduce(self, x):
ierr = -1
global_x = 0.0
mpi_allreduce(x, global_x, 1, MPI_DOUBLE, MPI_SUM, self.comm_cart,
ierr)
print(global_x, x)
# ... Computation of u at the n+1 iteration
for i,j in mesh.indices:
u_new[i, j] = c0 * (c1*(u[i+1, j] + u[i-1, j]) + c2*(u[i, j+1] + u[i, j-1]) - f[i, j])
# ...
# ... Computation of the global error
u_error = 0.0
for i,j in mesh.indices:
u_error += abs(u[i,j]-u_new[i,j])
local_error = u_error/(ntx*nty)
# Reduction
ierr = -1
global_error = 0.0
mpi_allreduce (local_error, global_error, 1, MPI_DOUBLE, MPI_SUM, mesh.comm_cart, ierr)
# ...
# ...
if (global_error < tol) or (it == n_iterations - 1):
if mesh.rank == 0:
print ("> convergence after ", it, " iterations")
print (" local error = ", local_error)
print (" global error = ", global_error)
break
# ...
del mesh
mpi_finalize(ierr)
for i in range(sx, ex + 1):
for j in range(sy, ey + 1):
u_new[i, j] = c0 * (c1 * (u[i + 1, j] + u[i - 1, j]) + c2 *
(u[i, j + 1] + u[i, j - 1]) - f[i, j])
# ...
# ... Computation of the global error
u_error = 0.0
for i in range(sx, ex + 1):
for j in range(sy, ey + 1):
u_error += abs(u[i, j] - u_new[i, j])
local_error = u_error / (ntx * nty)
# Reduction
global_error = 0.0
mpi_allreduce(local_error, global_error, 1, MPI_DOUBLE, MPI_SUM, comm_2d,
ierr)
# ...
# ...
if (global_error < tol) or (it == n_iterations - 1):
if rank == 0:
print("> convergence after ", it, " iterations")
print(" local error = ", local_error)
print(" global error = ", global_error)
break
# ...
# Free the datatype
mpi_type_free(type_line, ierr)
mpi_type_free(type_column, ierr)
from pyccel.stdlib.parallel.mpi import mpi_comm_rank
from pyccel.stdlib.parallel.mpi import mpi_comm_world
from pyccel.stdlib.parallel.mpi import mpi_status_size
from pyccel.stdlib.parallel.mpi import mpi_allreduce
from pyccel.stdlib.parallel.mpi import MPI_INTEGER
from pyccel.stdlib.parallel.mpi import MPI_PROD
# we need to declare these variables somehow,
# since we are calling mpi subroutines
ierr = -1
size = -1
rank = -1
mpi_init(ierr)
comm = mpi_comm_world
mpi_comm_size(comm, size, ierr)
mpi_comm_rank(comm, rank, ierr)
if rank == 0:
value = 1000
else:
value = rank
product_value = 0
mpi_allreduce (value, product_value, 1, MPI_INTEGER, MPI_PROD, comm, ierr)
print('I, process ', rank,', have the global product value ', product_value)
mpi_finalize(ierr)