#!/usr/bin/env python
###
#########################################################
#
#  Main file for parallel mesh testing. Runs an advection
# flow simulation using a rectangular mesh
#
#
#  Authors: Steve Roberts June 2005
#  Modified by Linda Stals April 2006
#
#
#########################################################


import sys
from os import sep
sys.path.append('..'+sep+'pyvolution')

# Parallel communication routines

import pypar

#  Mesh partition routines

from parallel_meshes import parallel_rectangle

# Parallel Domain
 
from parallel_advection import Parallel_Domain
from parallel_advection import Transmissive_boundary

############################
# Set the initial conditions
############################
class Set_Stage:
    """Set an initial condition with constant water height, for x<x0
    """

    def __init__(self, x0=0.25, x1=0.5, h=1.0):
        self.x0 = x0
        self.x1 = x1
        self.h  = h

    def __call__(self, x, y):
        return self.h*((x>self.x0)&(x<self.x1))

###############################
# Read in processor information
###############################

numprocs = pypar.size()
myid = pypar.rank()
processor_name = pypar.Get_processor_name()

N = 20
M = 20

#######################
# Partition the domain
#######################

# Build a unit mesh, subdivide it over numproces processors with each
# submesh containing M*N nodes

points, vertices, boundary, full_send_dict, ghost_recv_dict =  \
    parallel_rectangle(N, M, len1_g=1.0)

###########################################
# Start the computations on each subpartion
###########################################

# Create advection domain with direction (1,-1)
# Initial condition is zero by default

domain = Parallel_Domain(points, vertices, boundary,
                         full_send_dict, ghost_recv_dict, velocity=[1.0, 0.0])

# Turn on the visualisation

rect = [0.0, 0.0, 1.0, 1.0]
domain.initialise_visualiser(rect=rect)

# Boundaries

T = Transmissive_boundary(domain)
domain.default_order = 2
domain.set_boundary( {'left': T, 'right': T, 'bottom': T, 'top': T, \
                      'ghost': None} )

# Ensure that the domain definitions make sense

domain.check_integrity()

# Set the inititial conditions

domain.set_quantity('stage', Set_Stage(0.2,0.4,1.0))

# Let processor 0 output some timing information

if myid == 0:
    import time
    t0 = time.time()

# Start the evolve computions

for t in domain.evolve(yieldstep = 0.1, finaltime = 3.0):
    if myid == 0:
        domain.write_time()

# Output some computation statistics

if myid == 0:
    print 'That took %.2f seconds' %(time.time()-t0)
    print 'Communication time %.2f seconds'\
          %domain.communication_time
    print 'Reduction Communication time %.2f seconds'\
          %domain.communication_reduce_time