/[escript]/trunk/doc/examples/cookbook/example07a.py
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Revision 3001 - (hide annotations)
Wed Mar 31 04:29:10 2010 UTC (10 years, 4 months ago) by ahallam
Original Path: trunk/doc/examples/cookbook/example07.py
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Pressue wave problem, looking at sampling theorem, and Crank-Nicolson
1 ahallam 3001
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     # Antony Hallam
23     # Acoustic Wave Equation Simulation
24    
25     # Importing all the necessary modules required.
26     from esys.escript import *
27     from esys.finley import Rectangle
28     import sys
29     import os
30     # smoothing operator
31     from esys.escript.pdetools import Projector
32     import numpy as np
33     import pylab as pl
34     import matplotlib.cm as cm
35     from esys.escript.linearPDEs import LinearPDE
36    
37     # Establish a save path.
38     savepath = "data/example07"
39     mkDir(savepath)
40    
41     #Geometric and material property related variables.
42     mx = 1000. # model lenght
43     my = 1000. # model width
44     ndx = 400 # steps in x direction
45     ndy = 400 # steps in y direction
46    
47     xstep=mx/ndx
48     ystep=my/ndy
49    
50     c=380.0
51     csq=c*c
52     # Time related variables.
53     tend=1.5 #end time
54     #calculating )the timestep
55     h=tend/1000.
56     #Check to make sure number of time steps is not too large.
57     print "Time step size= ",h, "Expected number of outputs= ",tend/h
58    
59     #uncomment the following lines to give the user a chance to stop
60     #proceeder = raw_input("Is this ok?(y/n)")
61     #Exit if user thinks too many outputs.
62     #if proceeder == "n":
63     # sys.exit()
64    
65     U0=0.01 # amplitude of point source
66     # spherical source at middle of bottom face
67    
68     xc=[500,500]
69    
70     mydomain=Rectangle(l0=mx,l1=my,n0=ndx, n1=ndy)
71     #wavesolver2d(mydomain,h,tend,lam,mu,rho,U0,xc,savepath,output="mpl")
72     x=mydomain.getX()
73    
74     # ... open new PDE ...
75     mypde=LinearPDE(mydomain)
76     print mypde.isUsingLumping()
77     print mypde.getSolverOptions()
78     #mypde.getSolverOptions().setSolverMethod(mypde.getSolverOptions().LUMPING)
79     mypde.setSymmetryOn()
80     #kmat = kronecker(mydomain)
81     mypde.setValue(D=1.)#kmat)
82    
83     # define small radius around point xc
84     # Lsup(x) returns the maximum value of the argument x
85     src_radius = 30#2*Lsup(domain.getSize())
86     print "src_radius = ",src_radius
87    
88     # ... set initial values ....
89     n=0
90     # for first two time steps
91     u=U0*(cos(length(x-xc)*3.1415/src_radius)+1)*whereNegative(length(x-xc)-src_radius)
92     u_m1=u
93     t=0
94    
95     #plot source shape
96     uT=np.array(u.toListOfTuples())
97     uT=np.reshape(uT,(ndx+1,ndy+1))
98     source_line=uT[ndx/2,:]
99     pl.plot(source_line)
100     pl.plot(source_line,'ro')
101     pl.axis([70,130,0,0.2])
102     pl.savefig(os.path.join(savepath,"source_line.png"))
103     #~ u_pc_x1 = u_pot[0,0]
104     #~ u_pc_y1 = u_pot[0,1]
105     #~ u_pc_x2 = u_pot[1,0]
106     #~ u_pc_y2 = u_pot[1,1]
107     #~ u_pc_x3 = u_pot[2,0]
108     #~ u_pc_y3 = u_pot[2,1]
109     #~
110     #~ # open file to save displacement at point source
111     #~ u_pc_data=open(os.path.join(savepath,'U_pc.out'),'w')
112     #~ u_pc_data.write("%f %f %f %f %f %f %f\n"%(t,u_pc_x1,u_pc_y1,u_pc_x2,u_pc_y2,u_pc_x3,u_pc_y3))
113    
114     while t<tend:
115     # ... get current stress ....
116     # t=1.
117     ##OLD WAY
118     g=grad(u)
119     pres=csq*h*h*g
120     ### ... get new acceleration ....
121     #mypde.setValue(X=-stress)
122     #a=mypde.getSolution()
123     ### ... get new displacement ...
124     #u_p1=2*u-u_m1+h*h*a
125     ###NEW WAY
126     mypde.setValue(X=-pres,Y=(2.*u-u_m1))
127     u_p1 = mypde.getSolution()
128     # ... shift displacements ....
129     u_m1=u
130     u=u_p1
131     #stress =
132     t+=h
133     n+=1
134     print n,"-th time step t ",t
135     #~ u_pot = cbphones(domain,u,[[300.,200.],[500.,200.],[750.,200.]],2)
136     #~
137     #~ # print "u at point charge=",u_pc
138     #~ u_pc_x1 = u_pot[0,0]
139     #~ u_pc_y1 = u_pot[0,1]
140     #~ u_pc_x2 = u_pot[1,0]
141     #~ u_pc_y2 = u_pot[1,1]
142     #~ u_pc_x3 = u_pot[2,0]
143     #~ u_pc_y3 = u_pot[2,1]
144    
145     # save displacements at point source to file for t > 0
146     #~ u_pc_data.write("%f %f %f %f %f %f %f\n"%(t,u_pc_x1,u_pc_y1,u_pc_x2,u_pc_y2,u_pc_x3,u_pc_y3))
147    
148     # ... save current acceleration in units of gravity and displacements
149     saveVTK(os.path.join(savepath,"tonysol.%i.vtu"%n),output1 = length(u),tensor=pres)
150    
151    
152     #~ u_pc_data.close()
153     #~ os.system("mencoder mf://"+savepath+"/*.png -mf type=png:\
154     #~ w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o \
155     #~ wsmpl.avi")
156    
157     #mencoder mf://*.png -mf type=png:\w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o wsmpl.avi

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