class ConvectionTerm(FaceTerm):
"""
.. attention:: This class is abstract. Always create one of its subclasses.
"""
def __init__(self, coeff=1.0, diffusionTerm=None):
"""
Create a `ConvectionTerm` object.
>>> from fipy.meshes.grid1D import Grid1D
>>> from fipy.variables.cellVariable import CellVariable
>>> from fipy.variables.faceVariable import FaceVariable
>>> m = Grid1D(nx = 2)
>>> cv = CellVariable(mesh = m)
>>> fv = FaceVariable(mesh = m)
>>> vcv = CellVariable(mesh=m, rank=1)
>>> vfv = FaceVariable(mesh=m, rank=1)
>>> __ConvectionTerm(coeff = cv)
Traceback (most recent call last):
...
TypeError: The coefficient must be a vector value.
>>> __ConvectionTerm(coeff = fv)
Traceback (most recent call last):
...
TypeError: The coefficient must be a vector value.
>>> __ConvectionTerm(coeff = vcv)
__ConvectionTerm(coeff=_ArithmeticCellToFaceVariable(value=array([[ 0., 0., 0.]]), mesh=UniformGrid1D(dx=1.0, nx=2)))
>>> __ConvectionTerm(coeff = vfv)
__ConvectionTerm(coeff=FaceVariable(value=array([[ 0., 0., 0.]]), mesh=UniformGrid1D(dx=1.0, nx=2)))
>>> __ConvectionTerm(coeff = (1,))
__ConvectionTerm(coeff=(1,))
>>> from fipy.terms.explicitUpwindConvectionTerm import ExplicitUpwindConvectionTerm
>>> ExplicitUpwindConvectionTerm(coeff = (0,)).solve(var = cv)
>>> ExplicitUpwindConvectionTerm(coeff = 1).solve(var = cv)
Traceback (most recent call last):
...
TypeError: The coefficient must be a vector value.
>>> from fipy.meshes.grid2D import Grid2D
>>> m2 = Grid2D(nx=2, ny=1)
>>> cv2 = CellVariable(mesh=m2)
>>> vcv2 = CellVariable(mesh=m2, rank=1)
>>> vfv2 = FaceVariable(mesh=m2, rank=1)
>>> __ConvectionTerm(coeff=vcv2)
__ConvectionTerm(coeff=_ArithmeticCellToFaceVariable(value=array([[ 0., 0., 0., 0., 0., 0., 0.],
[ 0., 0., 0., 0., 0., 0., 0.]]), mesh=UniformGrid2D(dx=1.0, nx=2, dy=1.0, ny=1)))
>>> __ConvectionTerm(coeff=vfv2)
__ConvectionTerm(coeff=FaceVariable(value=array([[ 0., 0., 0., 0., 0., 0., 0.],
[ 0., 0., 0., 0., 0., 0., 0.]]), mesh=UniformGrid2D(dx=1.0, nx=2, dy=1.0, ny=1)))
>>> ExplicitUpwindConvectionTerm(coeff = ((0,),(0,))).solve(var=cv2)
>>> ExplicitUpwindConvectionTerm(coeff = (0,0)).solve(var=cv2)
:Parameters:
- `coeff` : The `Term`'s coefficient value.
- `diffusionTerm` : **deprecated**. The Peclet number is calculated automatically.
"""
if self.__class__ is ConvectionTerm:
raise NotImplementedError, "can't instantiate abstract base class"
if diffusionTerm is not None:
import warnings
warnings.warn("The Peclet number is calculated automatically. diffusionTerm will be ignored.", DeprecationWarning, stacklevel=2)
self.stencil = None
if isinstance(coeff, _MeshVariable) and coeff.getRank() != 1:
raise TypeError, "The coefficient must be a vector value."
if isinstance(coeff, CellVariable):
coeff = coeff.getArithmeticFaceValue()
FaceTerm.__init__(self, coeff = coeff)
def _calcGeomCoeff(self, mesh):
if not isinstance(self.coeff, FaceVariable):
self.coeff = FaceVariable(mesh=mesh, value=self.coeff, rank=1)
projectedCoefficients = self.coeff * mesh._getOrientedAreaProjections()
return projectedCoefficients.sum(0)
def _getWeight(self, mesh, equation=None):
if self.stencil is None:
small = -1e-20
if equation is None:
diffCoeff = small
else:
diffCoeff = equation._getDiffusiveGeomCoeff(mesh)
if diffCoeff is None:
diffCoeff = small
else:
diffCoeff = diffCoeff.getNumericValue()
diffCoeff = (diffCoeff == 0) * small + diffCoeff
alpha = self._Alpha(-self._getGeomCoeff(mesh) / diffCoeff)
self.stencil = {'implicit' : {'cell 1 diag' : alpha,
'cell 1 offdiag' : (1-alpha),
'cell 2 diag' : -(1-alpha),
'cell 2 offdiag' : -alpha}}
return self.stencil
def _getDefaultSolver(self, solver, *args, **kwargs):
if solver and not solver._canSolveAsymmetric():
import warnings
warnings.warn("%s cannot solve assymetric matrices" % solver)
return solver or DefaultAsymmetricSolver(*args, **kwargs)
def _verifyCoeffType(self, var):
if not (isinstance(self.coeff, FaceVariable) and self.coeff.getRank() == 1) \
and numerix.getShape(self.coeff) != (var.getMesh().getDim(),):
raise TypeError, "The coefficient must be a vector value."
def __add__(self, other):
if isinstance(other, ConvectionTerm):
if other.__class__ != self.__class__:
raise TypeError, "ConvectionTerms must use the same scheme: %s != %s" % (self.__class__.__name__, other.__class__.__name__)
return self.__class__(coeff=self.coeff + other.coeff)
else:
return FaceTerm.__add__(self, other)
