Problem with evaluation at a point in parallel

6

Hi, consider

from mpi4py import MPI as pyMPI
import numpy as np


def mpi4py_comm(comm):
    '''Get mpi4py communicator'''
    try:
        return comm.tompi4py()
    except AttributeError:
        return comm

    
def peval(f, x):
    '''Parallel synced eval'''
    try:
        yloc = f(x)
    except RuntimeError:
        yloc = np.inf*np.ones(f.value_shape())

    comm = mpi4py_comm(f.function_space().mesh().mpi_comm())
    yglob = np.zeros_like(yloc)
    comm.Allreduce(yloc, yglob, op=pyMPI.MIN)

    return yglob

# -------------------------------------------------------------------

if __name__ == '__main__':
    from dolfin import (UnitSquareMesh, Function, FunctionSpace, interpolate,
                        Expression, VectorFunctionSpace)

    mesh = UnitSquareMesh(32, 32)
    V = VectorFunctionSpace(mesh, 'CG', 1)
    f_ = Expression(('x[0]+x[1]', 'x[0]'), degree=1)
    f = interpolate(f_, V)

    x = np.array([0.5, 0.5])
    assert(np.linalg.norm(f_(x) - peval(f, x)) < 1E-13)
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