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import dolfin
import ufl
import libadjoint
class TimeConstant(object):
def __init__(self, label):
self.label = label
def __repr__(self):
return 'TimeConstant("'+self.label+'")'
class StartTimeConstant(TimeConstant):
def __init__(self):
TimeConstant.__init__(self, "START_TIME")
def __cmp__(self, other):
if isinstance(other, StartTimeConstant):
return 0
return -1
def __repr__(self):
return "StartTimeConstant()"
class FinishTimeConstant(TimeConstant):
def __init__(self):
TimeConstant.__init__(self, "FINISH_TIME")
def __cmp__(self, other):
if isinstance(other, FinishTimeConstant):
return 0
return 1
def __repr__(self):
return "FinishTimeConstant()"
class NoTime(TimeConstant):
def __init__(self, msg=""):
TimeConstant.__init__(self, msg)
def __cmp__(self, other):
if isinstance(other, StartTimeConstant):
return 1
elif isinstance(other, FinishTimeConstant):
return -1
else:
raise libadjoint.exceptions.LibadjointErrorInvalidInputs("Invalid time information: "+self.label)
def __repr__(self):
return "NoTimeConstant("+self.label+")"
START_TIME = StartTimeConstant()
FINISH_TIME = FinishTimeConstant()
def timeslice(inslice):
'''Preprocess a time slice, replacing the start with START_TIME and
stop with FINISH_TIME.'''
if not isinstance(inslice, slice):
return inslice
if inslice.start is None:
start = START_TIME
else:
start = inslice.start
if inslice.stop is None:
stop = FINISH_TIME
else:
stop = inslice.stop
if stop<=start:
raise libadjoint.exceptions.LibadjointErrorInvalidInputs(
"Zero or negative length time slice.")
return slice(start, stop, inslice.step)
class TimeTerm(object):
'''A form evaluated at a point in time or over a time integral.'''
def __init__(self, form, time):
self.form = form
self.time = time
def __repr__(self):
return "TimeTerm("+self.form.__repr__()+",time = "+\
repr(self.time)+")"
def __neg__(self):
return TimeTerm(-self.form,self.time)
class TimeForm(object):
def __init__(self, terms):
try:
self.terms = list(terms)
except TypeError:
self.terms = [terms]
def __radd__(self, other):
return self.__add__(other)
def __add__(self, other):
# Adding occurs by concatenating terms in the forms list.
if isinstance(other, TimeForm):
sum = TimeForm(self.terms + other.terms)
return sum
elif isinstance(other, ufl.form.Form):
sum = TimeForm(self.terms + (other*dt[FINISH_TIME]).terms)
return sum
elif other in [0, 0.0]:
return self
else:
return NotImplemented
def __sub__(self, other):
# Subtract by adding the negation of all the terms.
if isinstance(other, TimeForm):
sum = TimeForm(self.terms + [-term for term in other.terms])
return sum
else:
return NotImplemented
def __neg__(self):
# Unary negation occurs by negating the terms.
neg = TimeForm([-term for term in other.terms])
return neg
def __repr__(self):
return "TimeForm("+repr(self.terms)+")"
class TimeMeasure(object):
'''Define a measure for an integral over some interval in time.'''
def __init__(self, interval = None):
if interval is None:
interval = slice(START_TIME,FINISH_TIME,None)
self.interval = timeslice(interval)
def __getitem__(object, key):
return TimeMeasure(timeslice(key))
def __rmul__(self, other):
if isinstance(other, ufl.form.Form):
# Multiplication with a form produces the TimeForm.
return TimeForm(TimeTerm(other, self.interval))
else:
return NotImplemented
def __repr__(self):
return "TimeMeasure(interval = "+repr(self.interval)+")"
dt = TimeMeasure()
if __name__ == "__main__":
from dolfin import *
mesh = UnitSquare(2,2)
U = FunctionSpace(mesh, "Lagrange", 1)
v = TestFunction(U)
F = v*dx
TF = F*dt
AT = at_time(F,0.0)
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