/[escript]/trunk/escript/py_src/heat.py
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revision 1809 by ksteube, Thu Sep 25 06:43:44 2008 UTC revision 2337 by gross, Thu Mar 26 07:07:42 2009 UTC
# Line 37  import util Line 37  import util
37  from linearPDEs import TransportPDE  from linearPDEs import TransportPDE
38    
39  class TemperatureCartesian(TransportPDE):  class TemperatureCartesian(TransportPDE):
40        """      """
41        solves      Represents and solves the temperature advection-diffusion problem
42    
43            rhocp(T_{,t} + v_i T_{,i} - ( k T_{,i})_i = Q      M{rhocp(T_{,t} + v_i T_{,i} - ( k T_{,i})_i = Q}
44            
45                   k T_{,i}*n_i=surface_flux      M{k T_{,i}*n_i=surface_flux} and M{T_{,t} = 0} where C{given_T_mask}>0.
46                
47                   T_{,t} = 0  where given_T_mask>0      If surface_flux is not given 0 is assumed.
48    
49        if surface_flux is not give 0 is assumed.      Typical usage::
50    
51        typical usage:          sp = TemperatureCartesian(domain)
52            sp.setTolerance(1.e-4)
53              sp=TemperatureCartesian(domain)          t = 0
54              sp.setTolerance(1.e-4)          T = ...
55              t=0          sp.setValues(rhocp=...,  v=..., k=..., given_T_mask=...)
56              T=...          sp.setInitialTemperature(T)
57              sp.setValues(rhocp = ..,  v=.., k=.., given_T_mask=..)          while t < t_end:
58              sp.setInitialTemperature(T)              sp.setValue(Q=...)
59              while t < t_end:              T = sp.getTemperature(dt)
60                  sp.setValue(Q= ...)              t += dt
61                  T=sp.getTemperature(dt)      """
62                  t+=dt      def __init__(self,domain,useBackwardEuler=False,**kwargs):
       """  
       def __init__(self,domain,theta=0.5,**kwargs):  
63          """          """
64          initializes tmperature advection-diffuision problem          Initializes the temperature advection-diffusion problem.
65    
66          @param domain: domain of the problem          @param domain: domain of the problem
67          @param theta: method control: theta=1. backward Euler          @param useBackwardEuler: if set the backward Euler scheme is used. Otherwise the Crank-Nicholson scheme is applied. Not that backward Euler scheme will return a safe time step size which is practically infinity as the scheme is unconditional unstable. So other measures need to be applied to control the time step size. The Crank-Nicholson scheme provides a higher accuracy but requires to limit the time step size to be stable.
68                                        theta=0.5: Crank-Nicholson scheme          @type useBackwardEuler: C{bool}
                                       thete=0.: forward Euler (not recommendable)  
69          """          """
70          TransportPDE.__init__(self,domain,num_equations=1,theta=theta,**kwargs)          TransportPDE.__init__(self,domain,numEquations=1,useBackwardEuler=useBackwardEuler,**kwargs)
71          self.setReducedOn()          self.setReducedOrderOn()
72          self.__rhocp=None          self.__rhocp=None
73          self.__v=None          self.__v=None
74        def setInitialTemperature(self,T):  
75        def setInitialTemperature(self,T):
76            """
77            Same as L{setInitialSolution}.
78            """
79          self.setInitialSolution(T)          self.setInitialSolution(T)
80        def setValue(self,rhocp=None,v=None,k=None,Q=None,surface_flux=None,given_T_mask=None):  
81             if rhocp!=None:      def setValue(self,rhocp=None,v=None,k=None,Q=None,surface_flux=None,given_T_mask=None):
82                 self.__rhocp=rhocp          if rhocp!=None:
83             if v!=None:              self.__rhocp=rhocp
84                 self.__v=v          if v!=None:
85             if rhocp!=None:              self.__v=v
86                 super(TemperatureCartesian,self).setValue(M=self.__rhocp)          if rhocp!=None:
87             if (rhocp!=None or v!=None) and self.__rhocp!=None and self.__v!=None:              super(TemperatureCartesian,self).setValue(M=self.__rhocp)
88                 super(TemperatureCartesian,self).setValue(C=-self.__rhocp*self.__v)          if (rhocp!=None or v!=None) and self.__rhocp!=None and self.__v!=None:
89             if k!=None:              super(TemperatureCartesian,self).setValue(C=-self.__rhocp*self.__v)
90                 super(TemperatureCartesian,self).setValue(A=-k*util.kronecker(self.getDomain()))          if k!=None:
91             if Q!=None:              super(TemperatureCartesian,self).setValue(A=-k*util.kronecker(self.getDomain()))
92                 super(TemperatureCartesian,self).setValue(Y=Q)          if Q!=None:
93             if surface_flux!=None:              super(TemperatureCartesian,self).setValue(Y=Q)
94                 super(TemperatureCartesian,self).setValue(y=surface_flux)          if surface_flux!=None:
95             if given_T_mask!=None:              super(TemperatureCartesian,self).setValue(y=surface_flux)
96                 super(TemperatureCartesian,self).setValue(q=given_T_mask)          if given_T_mask!=None:
97                          super(TemperatureCartesian,self).setValue(q=given_T_mask)
98        def getTemperature(self,dt,**kwargs):  
99            return self.solve(dt,**kwargs)      def getTemperature(self,dt,**kwargs):
100            """
101            Same as L{getSolution}.
102            """
103            return self.getSolution(dt,**kwargs)
104    

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