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from __future__ import division, print_function
##############################################################################
#
# Copyright (c) 2009-2018 by The University of Queensland
# http://www.uq.edu.au
#
# Primary Business: Queensland, Australia
# Licensed under the Apache License, version 2.0
# http://www.apache.org/licenses/LICENSE-2.0
#
# Development until 2012 by Earth Systems Science Computational Center (ESSCC)
# Development 2012-2013 by School of Earth Sciences
# Development from 2014 by Centre for Geoscience Computing (GeoComp)
#
##############################################################################
__copyright__="""Copyright (c) 2009-2018 by The University of Queensland
http://www.uq.edu.au
Primary Business: Queensland, Australia"""
__license__="""Licensed under the Apache License, version 2.0
http://www.apache.org/licenses/LICENSE-2.0"""
__url__="https://launchpad.net/escript-finley"
############################################################FILE HEADER
# example08a.py
# Antony Hallam
# Seismic Wave Equation Simulation using acceleration solution.
#######################################################EXTERNAL MODULES
from esys.escript import *
from esys.weipa import saveVTK
import sys
import os
# smoothing operator
from esys.escript.pdetools import Projector, Locator
from esys.escript.unitsSI import *
import numpy as np
from esys.escript.linearPDEs import LinearPDE, SolverOptions
try:
# This imports the rectangle domain function
from esys.finley import Rectangle
HAVE_FINLEY = True
except ImportError:
print("Finley module not available")
HAVE_FINLEY = False
########################################################MPI WORLD CHECK
if getMPISizeWorld() > 1:
import sys
print("This example will not run in an MPI world.")
sys.exit(0)
if HAVE_FINLEY:
#################################################ESTABLISHING VARIABLES
# where to save output data
savepath = "data/example08a"
mkDir(savepath)
#Geometric and material property related variables.
mx = 1000. # model lenght
my = -1000. # model width
ndx = 500 # steps in x direction
ndy = 500 # steps in y direction
xstep=mx/ndx # calculate the size of delta x
ystep=abs(my/ndy) # calculate the size of delta y
lam=3.462e9 #lames constant
mu=3.462e9 #bulk modulus
rho=1154. #density
# Time related variables.
testing=True
if testing:
print('The testing end time is currently selected. This severely limits the number of time iterations.')
print("Try changing testing to False for more iterations.")
tend=0.001
else:
tend=0.5 # end time
h=0.0005 # time step
# data recording times
rtime=0.0 # first time to record
rtime_inc=tend/20.0 # time increment to record
#Check to make sure number of time steps is not too large.
print("Time step size= ",h, "Expected number of outputs= ",tend/h)
U0=0.01 # amplitude of point source
# will introduce a spherical source at middle left of bottom face
xc=[mx/2,0]
####################################################DOMAIN CONSTRUCTION
domain=Rectangle(l0=mx,l1=my,n0=ndx, n1=ndy) # create the domain
x=domain.getX() # get the locations of the nodes in the domani
##########################################################ESTABLISH PDE
mypde=LinearPDE(domain) # create pde
mypde.setSymmetryOn() # turn symmetry on
# turn lumping on for more efficient solving
mypde.getSolverOptions().setSolverMethod(SolverOptions.HRZ_LUMPING)
kmat = kronecker(domain) # create the kronecker delta function of the domain
mypde.setValue(D=kmat*rho) #set the general form value D
############################################FIRST TIME STEPS AND SOURCE
# define small radius around point xc
src_length = 20; print("src_length = ",src_length)
# set initial values for first two time steps with source terms
y=U0*(cos(length(x-xc)*3.1415/src_length)+1)*whereNegative(length(x-xc)-src_length)
src_dir=np.array([0.,-1.]) # defines direction of point source as down
y=y*src_dir
mypde.setValue(y=y) #set the source as a function on the boundary
# initial value of displacement at point source is constant (U0=0.01)
# for first two time steps
u=[0.0,0.0]*whereNegative(x)
u_m1=u
####################################################ITERATION VARIABLES
n=0 # iteration counter
t=0 # time counter
##############################################################ITERATION
while t<tend:
# get current stress
g=grad(u); stress=lam*trace(g)*kmat+mu*(g+transpose(g))
mypde.setValue(X=-stress) # set PDE values
accel = mypde.getSolution() #get PDE solution for accelleration
u_p1=(2.*u-u_m1)+h*h*accel #calculate displacement
u_m1=u; u=u_p1 # shift values by 1
# save current displacement, acceleration and pressure
if (t >= rtime):
saveVTK(os.path.join(savepath,"ex08a.%05d.vtu"%n),displacement=length(u),\
acceleration=length(accel),tensor=stress)
rtime=rtime+rtime_inc #increment data save time
# increment loop values
t=t+h; n=n+1
print("time step %d, t=%s"%(n,t))
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