/[escript]/trunk/doc/examples/cookbook/example07a.py
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Annotation of /trunk/doc/examples/cookbook/example07a.py

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Wed Feb 7 02:12:08 2018 UTC (2 years, 5 months ago) by jfenwick
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1 sshaw 5288 from __future__ import division, print_function
2 jfenwick 3981 ##############################################################################
3 ahallam 3001 #
4 jfenwick 6651 # Copyright (c) 2009-2018 by The University of Queensland
5 jfenwick 3981 # http://www.uq.edu.au
6 ahallam 3001 #
7     # Primary Business: Queensland, Australia
8 jfenwick 6112 # Licensed under the Apache License, version 2.0
9     # http://www.apache.org/licenses/LICENSE-2.0
10 ahallam 3001 #
11 jfenwick 3981 # Development until 2012 by Earth Systems Science Computational Center (ESSCC)
12 jfenwick 4657 # Development 2012-2013 by School of Earth Sciences
13     # Development from 2014 by Centre for Geoscience Computing (GeoComp)
14 jfenwick 3981 #
15     ##############################################################################
16 ahallam 3001
17 jfenwick 6651 __copyright__="""Copyright (c) 2009-2018 by The University of Queensland
18 jfenwick 3981 http://www.uq.edu.au
19 ahallam 3001 Primary Business: Queensland, Australia"""
20 jfenwick 6112 __license__="""Licensed under the Apache License, version 2.0
21     http://www.apache.org/licenses/LICENSE-2.0"""
22 ahallam 3001 __url__="https://launchpad.net/escript-finley"
23    
24 ahallam 3025 ############################################################FILE HEADER
25     # example07a.py
26 ahallam 3001 # Antony Hallam
27 ahallam 3025 # Acoustic Wave Equation Simulation using displacement solution
28 ahallam 3001
29 ahallam 3025 #######################################################EXTERNAL MODULES
30 caltinay 4087 import matplotlib
31     matplotlib.use('agg') #It's just here for automated testing
32 ahallam 3001 from esys.escript import *
33     from esys.finley import Rectangle
34 caltinay 3346 from esys.weipa import saveVTK
35 ahallam 3001 import sys
36     import os
37     # smoothing operator
38 ahallam 3025 from esys.escript.pdetools import Projector, Locator
39     from esys.escript.unitsSI import *
40 ahallam 3001 import numpy as np
41     import pylab as pl
42     import matplotlib.cm as cm
43     from esys.escript.linearPDEs import LinearPDE
44    
45 sshaw 5288 try:
46     # This imports the rectangle domain function
47     from esys.finley import Rectangle
48     HAVE_FINLEY = True
49     except ImportError:
50     print("Finley module not available")
51     HAVE_FINLEY = False
52 ahallam 3025 ########################################################MPI WORLD CHECK
53     if getMPISizeWorld() > 1:
54 sshaw 4576 import sys
55     print("This example will not run in an MPI world.")
56     sys.exit(0)
57 ahallam 3025
58 sshaw 5288 if HAVE_FINLEY:
59     #################################################ESTABLISHING VARIABLES
60     # where to save output data
61     savepath = "data/example07a"
62     mkDir(savepath)
63     #Geometric and material property related variables.
64     mx = 1000. # model lenght
65     my = 1000. # model width
66     ndx = 400 # steps in x direction
67     ndy = 400 # steps in y direction
68     xstep=mx/ndx # calculate the size of delta x
69     ystep=my/ndy # calculate the size of delta y
70 ahallam 3001
71 sshaw 5288 c=380.0*m/sec # velocity of sound in air
72     csq=c*c #square of c
73     # Time related variables.
74     testing=True
75     if testing:
76     print('The testing end time is currently selected. This severely limits the number of time iterations.')
77     print("Try changing testing to False for more iterations.")
78     tend=0.004
79     else:
80     tend=1.5 # end time
81 ahallam 3195
82 sshaw 5288 h=0.001 # time step
83     # data recording times
84     rtime=0.0 # first time to record
85     rtime_inc=tend/20.0 # time increment to record
86     #Check to make sure number of time steps is not too large.
87     print("Time step size= ",h, "Expected number of outputs= ",tend/h)
88 ahallam 3001
89 sshaw 5288 U0=0.005 # amplitude of point source
90     # want a spherical source in the middle of area
91     xc=[500,500] # with reference to mx,my this is the source location
92 ahallam 3001
93 sshaw 5288 ####################################################DOMAIN CONSTRUCTION
94     mydomain=Rectangle(l0=mx,l1=my,n0=ndx, n1=ndy) # create the domain
95     x=mydomain.getX() # get the node locations of the domain
96 ahallam 3025
97 sshaw 5288 ##########################################################ESTABLISH PDE
98     mypde=LinearPDE(mydomain) # create pde
99     mypde.setSymmetryOn() # turn symmetry on
100     mypde.setValue(D=1.) # set the value of D in the general form to 1.
101 ahallam 3025
102 sshaw 5288 ############################################FIRST TIME STEPS AND SOURCE
103     # define small radius around point xc
104     src_radius = 30
105     print("src_radius = ",src_radius)
106     # set initial values for first two time steps with source terms
107     u=U0*(cos(length(x-xc)*3.1415/src_radius)+1)*whereNegative(length(x-xc)-src_radius)
108     u_m1=u
109     #plot source shape
110     cut_loc=[] #where the cross section of the source along x will be
111     src_cut=[] #where the cross section of the source will be
112     # create locations for source cross section
113     for i in range(ndx//2-ndx//10,ndx//2+ndx//10):
114     cut_loc.append(xstep*i)
115     src_cut.append([xstep*i,xc[1]])
116     # locate the nearest nodes to the points in src_cut
117     src=Locator(mydomain,src_cut)
118     src_cut=src.getValue(u) #retrieve the values from the nodes
119     # plot the x locations vs value and save the figure
120     pl.plot(cut_loc,src_cut)
121     pl.axis([xc[0]-src_radius*3,xc[0]+src_radius*3,0.,2.*U0])
122     pl.savefig(os.path.join(savepath,"source_line.png"))
123 ahallam 3001
124 sshaw 5288 ####################################################ITERATION VARIABLES
125     n=0 # iteration counter
126     t=0 # time counter
127     ##############################################################ITERATION
128     while t<tend:
129     g=grad(u); pres=csq*h*h*g # get current pressure
130     mypde.setValue(X=-pres,Y=(2.*u-u_m1)) # set values in pde
131     u_p1 = mypde.getSolution() # get the new displacement
132     u_m1=u; u=u_p1 # shift values back one time step for next iteration
133     # save current displacement, acceleration and pressure
134     if (t >= rtime):
135     saveVTK(os.path.join(savepath,"ex07a.%i.vtu"%n),displacement=length(u),tensor=pres)
136     rtime=rtime+rtime_inc #increment data save time
137     # increment loop values
138     t=t+h; n=n+1
139     print("time step %d, t=%s"%(n,t))

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