/[escript]/trunk/doc/examples/cookbook/example02.py
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Contents of /trunk/doc/examples/cookbook/example02.py

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Merging dudley and scons updates from branches

1
2 ########################################################
3 #
4 # Copyright (c) 2009 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 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 """
23 Author: Antony Hallam antony.hallam@uqconnect.edu.au
24 """
25
26 ############################################################FILE HEADER
27 # example02.py
28 # Model temperature diffusion along an insulated iron rod with a
29 # heating element at the left hand side.
30
31 #######################################################EXTERNAL MODULES
32 # To solve the problem it is necessary to import the modules we require.
33 from esys.escript import * # This imports everything from the escript library
34 from esys.escript.unitsSI import *
35 from esys.escript.linearPDEs import LinearPDE # This defines LinearPDE as LinearPDE
36 from esys.finley import Rectangle # This imports the rectangle domain function
37 #For interactive use, you can comment out the next two lines
38 import matplotlib
39 matplotlib.use('agg') #It's just here for automated testing
40 import pylab as pl #Plotting package.
41 import numpy as np #Array package.
42 import os, sys #This package is necessary to handle saving our data.
43
44 ########################################################MPI WORLD CHECK
45 if getMPISizeWorld() > 1:
46 import sys
47 print "This example will not run in an MPI world."
48 sys.exit(0)
49
50 #################################################ESTABLISHING VARIABLES
51 #Domain related.
52 mx = 1*m #meters - model length
53 my = .1*m #meters - model width
54 ndx = 100 # mesh steps in x direction
55 ndy = 1 # mesh steps in y direction - one dimension means one element
56 #PDE related
57 rho = 7874. *kg/m**3 #kg/m^{3} density of iron
58 cp = 449.*J/(kg*K) # J/Kg.K thermal capacity
59 rhocp = rho*cp
60 kappa = 80.*W/m/K # watts/m.Kthermal conductivity
61 qH=0 * J/(sec*m**3) # J/(sec.m^{3}) no heat source
62 Tref = 20 * Celsius # base temperature of the rod
63 T0 = 100 * Celsius # temperature at heating element
64
65 ################################################ESTABLISHING PARAMETERS
66 t=0 * day # our start time, usually zero
67 tend= 0.5 *day # - time to end simulation
68 outputs = 200 # number of time steps required.
69 h=(tend-t)/outputs #size of time step
70 #user warning statement
71 print "Expected Number of time outputs is: ", (tend-t)/h
72 i=0 #loop counter
73 #the folder to put our outputs in, leave blank "" for script path
74 save_path= os.path.join("data","example02")
75 #ensure the dir exists
76 mkDir(save_path, os.path.join(save_path,"tempT"))
77
78 ####################################################DOMAIN CONSTRUCTION
79 rod = Rectangle(l0=mx,l1=my,n0=ndx, n1=ndy)
80 x=Solution(rod).getX()
81 ###############################################ESCRIPT PDE CONSTRUCTION
82 mypde=LinearPDE(rod)
83 A=zeros((2,2))
84 A[0,0]=kappa
85 q=whereZero(x[0])
86 mypde.setValue(A=A, D=rhocp/h, q=q, r=T0)
87 # ... set initial temperature ....
88 T= T0*whereZero(x[0])+Tref*(1-whereZero(x[0]))
89
90 # ... open a collector for the time marks and corresponding total energy
91 t_list=[]
92 E_list=[]
93 # ... convert solution points for plotting
94 plx = x.toListOfTuples()
95 plx = np.array(plx) #convert to tuple to numpy array
96 plx = plx[:,0] #extract x locations
97 ########################################################START ITERATION
98 while t<tend:
99 i+=1
100 t+=h
101 mypde.setValue(Y=qH+rhocp/h*T)
102 T=mypde.getSolution()
103 totE=integrate(rhocp*T)
104 print "time step %s at t=%e minutes completed. total energy = %e."%(i,t/minute,totE)
105 t_list.append(t)
106 E_list.append(totE)
107
108 #establish figure 1 for temperature vs x plots
109 tempT = T.toListOfTuples()
110 pl.figure(1) #current figure
111 pl.plot(plx,tempT) #plot solution
112 # add title
113 pl.axis([0,mx,Tref*.9,T0*1.1])
114 pl.title("Temperature across rod at time %e hours"%(t/hour))
115 #save figure to file
116 pl.savefig(os.path.join(save_path,"tempT", "rodpyplot%03d.png"%i))
117 pl.clf() #clear figure
118
119 ###############################################################PLOTTING
120 # plot the total energy over time:
121 pl.figure(2)
122 pl.plot(t_list,E_list)
123 pl.title("Total Energy")
124 # pl.axis([0,max(t_list),0,max(E_list)*1.1])
125 pl.savefig(os.path.join(save_path,"totE.png"))
126 pl.clf()
127
128 #########################################################CREATE A MOVIE
129 # compile the *.png files to create a*.avi video that show T change
130 # with time. This opperation uses linux mencoder. For other operating
131 # systems it may be possible to use your favourite video compiler to
132 # convert image files to videos. To enable this step uncomment the
133 # following lines.
134
135 #os.system("mencoder mf://"+save_path+"/tempT"+"/*.png -mf type=png:\
136 #w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o \
137 #example02tempT.avi")

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