/[escript]/trunk/doc/examples/cookbook/example08a.py
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Contents of /trunk/doc/examples/cookbook/example08a.py

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Revision 3029 - (show annotations)
Fri May 21 02:01:37 2010 UTC (10 years, 2 months ago) by ahallam
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small updates and work on seismic code
1
2 ########################################################
3 #
4 # Copyright (c) 2009-2010 by University of Queensland
5 # Earth Systems Science Computational Center (ESSCC)
6 # http://www.uq.edu.au/esscc
7 #
8 # Primary Business: Queensland, Australia
9 # Licensed under the Open Software License version 3.0
10 # http://www.opensource.org/licenses/osl-3.0.php
11 #
12 ########################################################
13
14 __copyright__="""Copyright (c) 2009-2010 by University of Queensland
15 Earth Systems Science Computational Center (ESSCC)
16 http://www.uq.edu.au/esscc
17 Primary Business: Queensland, Australia"""
18 __license__="""Licensed under the Open Software License version 3.0
19 http://www.opensource.org/licenses/osl-3.0.php"""
20 __url__="https://launchpad.net/escript-finley"
21
22 ############################################################FILE HEADER
23 # example08a.py
24 # Antony Hallam
25 # Seismic Wave Equation Simulation using acceleration solution.
26
27 #######################################################EXTERNAL MODULES
28 from esys.escript import *
29 from esys.finley import Rectangle
30 import sys
31 import os
32 # smoothing operator
33 from esys.escript.pdetools import Projector, Locator
34 from esys.escript.unitsSI import *
35 import numpy as np
36 import pylab as pl
37 import matplotlib.cm as cm
38 from esys.escript.linearPDEs import LinearPDE
39
40 #################################################ESTABLISHING VARIABLES
41 # where to save output data
42 savepath = "data/example08a"
43 mkDir(savepath)
44 #Geometric and material property related variables.
45 mx = 1000. # model lenght
46 my = -1000. # model width
47 ndx = 200 # steps in x direction
48 ndy = 200 # steps in y direction
49 xstep=mx/ndx # calculate the size of delta x
50 ystep=abs(my/ndy) # calculate the size of delta y
51 lam=3.462e9 #lames constant
52 mu=3.462e9 #bulk modulus
53 rho=1154. #density
54 # Time related variables.
55 tend=1.5 # end time
56 h=0.001 # time step
57 # data recording times
58 rtime=0.0 # first time to record
59 rtime_inc=tend/20.0 # time increment to record
60 #Check to make sure number of time steps is not too large.
61 print "Time step size= ",h, "Expected number of outputs= ",tend/h
62
63 U0=0.01 # amplitude of point source
64 # will introduce a spherical source at middle left of bottom face
65 xc=[ndx/2-ndx/4,0]
66
67 ####################################################DOMAIN CONSTRUCTION
68 domain=Rectangle(l0=mx,l1=my,n0=ndx, n1=ndy) # create the domain
69 x=domain.getX() # get the locations of the nodes in the domani
70
71 ##########################################################ESTABLISH PDE
72 mypde=LinearPDE(domain) # create pde
73 mypde.setSymmetryOn() # turn symmetry on
74 # turn lumping on for more efficient solving
75 mypde.getSolverOptions().setSolverMethod(mypde.getSolverOptions().LUMPING)
76 kmat = kronecker(domain) # create the kronecker delta function of the domain
77 mypde.setValue(D=kmat*rho) #set the general form value D
78
79 ############################################FIRST TIME STEPS AND SOURCE
80 # define small radius around point xc
81 src_length = 20; print "src_length = ",src_length
82 # set initial values for first two time steps with source terms
83 y=U0*(cos(length(x-xc)*3.1415/src_length)+1)*whereNegative(length(x-xc)-src_length)
84 src_dir=numpy.array([0.,-1.]) # defines direction of point source as down
85 y=y*src_dir
86 mypde.setValue(y=y) #set the source as a function on the boundary
87 # initial value of displacement at point source is constant (U0=0.01)
88 # for first two time steps
89 u=[0.0,0.0]*whereNegative(x)
90 u_m1=u
91
92 ####################################################ITERATION VARIABLES
93 n=0 # iteration counter
94 t=0 # time counter
95 ##############################################################ITERATION
96 while t<tend:
97 # get current stress
98 g=grad(u); stress=lam*trace(g)*kmat+mu*(g+transpose(g))
99 mypde.setValue(X=-stress) # set PDE values
100 accel = mypde.getSolution() #get PDE solution for accelleration
101 u_p1=(2.*u-u_m1)+h*h*accel #calculate displacement
102 u_m1=u; u=u_p1 # shift values by 1
103 # save current displacement, acceleration and pressure
104 if (t >= rtime):
105 saveVTK(os.path.join(savepath,"ex08a.%05d.vtu"%n),displacement=length(u),\
106 acceleration=length(accel),tensor=stress)
107 rtime=rtime+rtime_inc #increment data save time
108 # increment loop values
109 t=t+h; n=n+1
110 print n,"-th time step t ",t

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