- both autoPtr and tmp are defined with an implicit construct from
nullptr (but with explicit construct from a pointer to null).
Thus is it safe to use 'nullptr' when returning an empty autoPtr or tmp.
- when constructing dimensioned fields that are to be zero-initialized,
it is preferrable to use a form such as
dimensionedScalar(dims, Zero)
dimensionedVector(dims, Zero)
rather than
dimensionedScalar("0", dims, 0)
dimensionedVector("zero", dims, vector::zero)
This reduces clutter and also avoids any suggestion that the name of
the dimensioned quantity has any influence on the field's name.
An even shorter version is possible. Eg,
dimensionedScalar(dims)
but reduces the clarity of meaning.
- NB: UniformDimensionedField is an exception to these style changes
since it does use the name of the dimensioned type (instead of the
regIOobject).
Improve alignment of its behaviour with std::unique_ptr
- element_type typedef
- release() method - identical to ptr() method
- get() method to get the pointer without checking and without releasing it.
- operator*() for dereferencing
Method name changes
- renamed rawPtr() to get()
- renamed rawRef() to ref(), removed unused const version.
Removed methods/operators
- assignment from a raw pointer was deleted (was rarely used).
Can be convenient, but uncontrolled and potentially unsafe.
Do allow assignment from a literal nullptr though, since this
can never leak (and also corresponds to the unique_ptr API).
Additional methods
- clone() method: forwards to the clone() method of the underlying
data object with argument forwarding.
- reset(autoPtr&&) as an alternative to operator=(autoPtr&&)
STYLE: avoid implicit conversion from autoPtr to object type in many places
- existing implementation has the following:
operator const T&() const { return operator*(); }
which means that the following code works:
autoPtr<mapPolyMesh> map = ...;
updateMesh(*map); // OK: explicit dereferencing
updateMesh(map()); // OK: explicit dereferencing
updateMesh(map); // OK: implicit dereferencing
for clarity it may preferable to avoid the implicit dereferencing
- prefer operator* to operator() when deferenced a return value
so it is clearer that a pointer is involve and not a function call
etc Eg, return *meshPtr_; vs. return meshPtr_();
- more consistent with STL practices for function classes.
- string::hash function class now operates on std::string rather
than Foam::string since we have now avoided inadvertent use of
string conversion from int in more places.
Now the interFoam and compressibleInterFoam families of solvers use the same
alphaEqn formulation and supporting all of the MULES options without
code-duplication.
The semi-implicit MULES support allows running with significantly larger
time-steps but this does reduce the interface sharpness.
When the GeometricBoundaryField template class was originally written it
was a separate class in the Foam namespace rather than a sub-class of
GeometricField as it is now. Without loss of clarity and simplifying
code which access the boundary field of GeometricFields it is better
that GeometricBoundaryField be renamed Boundary for consistency with the
new naming convention for the type of the dimensioned internal field:
Internal, see commit 4a57b9be2e
This is a very simple text substitution change which can be applied to
any code which compiles with the OpenFOAM-dev libraries.
Given that the type of the dimensioned internal field is encapsulated in
the GeometricField class the name need not include "Field"; the type
name is "Internal" so
volScalarField::DimensionedInternalField -> volScalarField::Internal
In addition to the ".dimensionedInternalField()" access function the
simpler "()" de-reference operator is also provided to greatly simplify
FV equation source term expressions which need not evaluate boundary
conditions. To demonstrate this kEpsilon.C has been updated to use
dimensioned internal field expressions in the k and epsilon equation
source terms.
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1938
Because C++ does not support overloading based on the return-type there
is a problem defining both const and non-const member functions which
are resolved based on the const-ness of the object for which they are
called rather than the intent of the programmer declared via the
const-ness of the returned type. The issue for the "boundaryField()"
member function is that the non-const version increments the
event-counter and checks the state of the stored old-time fields in case
the returned value is altered whereas the const version has no
side-effects and simply returns the reference. If the the non-const
function is called within the patch-loop the event-counter may overflow.
To resolve this it in necessary to avoid calling the non-const form of
"boundaryField()" if the results is not altered and cache the reference
outside the patch-loop when mutation of the patch fields is needed.
The most straight forward way of resolving this problem is to name the
const and non-const forms of the member functions differently e.g. the
non-const form could be named:
mutableBoundaryField()
mutBoundaryField()
nonConstBoundaryField()
boundaryFieldRef()
Given that in C++ a reference is non-const unless specified as const:
"T&" vs "const T&" the logical convention would be
boundaryFieldRef()
boundaryFieldConstRef()
and given that the const form which is more commonly used is it could
simply be named "boundaryField()" then the logical convention is
GeometricBoundaryField& boundaryFieldRef();
inline const GeometricBoundaryField& boundaryField() const;
This is also consistent with the new "tmp" class for which non-const
access to the stored object is obtained using the ".ref()" member function.
This new convention for non-const access to the components of
GeometricField will be applied to "dimensionedInternalField()" and "internalField()" in the
future, i.e. "dimensionedInternalFieldRef()" and "internalFieldRef()".
e.g. (fvc::interpolate(HbyA) & mesh.Sf()) -> fvc::flux(HbyA)
This removes the need to create an intermediate face-vector field when
computing fluxes which is more efficient, reduces the peak storage and
improved cache coherency in addition to providing a simpler and cleaner
API.
The deprecated non-const tmp functionality is now on the compiler switch
NON_CONST_TMP which can be enabled by adding -DNON_CONST_TMP to EXE_INC
in the Make/options file. However, it is recommended to upgrade all
code to the new safer tmp by using the '.ref()' member function rather
than the non-const '()' dereference operator when non-const access to
the temporary object is required.
Please report any problems on Mantis.
Henry G. Weller
CFD Direct.
To be used instead of zeroGradientFvPatchField for temporary fields for
which zero-gradient extrapolation is use to evaluate the boundary field
but avoiding fields derived from temporary field using field algebra
inheriting the zeroGradient boundary condition by the reuse of the
temporary field storage.
zeroGradientFvPatchField should not be used as the default patch field
for any temporary fields and should be avoided for non-temporary fields
except where it is clearly appropriate;
extrapolatedCalculatedFvPatchField and calculatedFvPatchField are
generally more suitable defaults depending on the manner in which the
boundary values are specified or evaluated.
The entire OpenFOAM-dev code-base has been updated following the above
recommendations.
Henry G. Weller
CFD Direct
The boundary conditions of HbyA are now constrained by the new "constrainHbyA"
function which applies the velocity boundary values for patches for which the
velocity cannot be modified by assignment and pressure extrapolation is
not specified via the new
"fixedFluxExtrapolatedPressureFvPatchScalarField".
The new function "constrainPressure" sets the pressure gradient
appropriately for "fixedFluxPressureFvPatchScalarField" and
"fixedFluxExtrapolatedPressureFvPatchScalarField" boundary conditions to
ensure the evaluated flux corresponds to the known velocity values at
the boundary.
The "fixedFluxPressureFvPatchScalarField" boundary condition operates
exactly as before, ensuring the correct flux at fixed-flux boundaries by
compensating for the body forces (gravity in particular) with the
pressure gradient.
The new "fixedFluxExtrapolatedPressureFvPatchScalarField" boundary
condition may be used for cases with or without body-forces to set the
pressure gradient to compensate not only for the body-force but also the
extrapolated "HbyA" which provides a second-order boundary condition for
pressure. This is useful for a range a problems including impinging
flow, extrapolated inlet conditions with body-forces or for highly
viscous flows, pressure-induced separation etc. To test this boundary
condition at walls in the motorBike tutorial case set
lowerWall
{
type fixedFluxExtrapolatedPressure;
}
motorBikeGroup
{
type fixedFluxExtrapolatedPressure;
}
Currently the new extrapolated pressure boundary condition is supported
for all incompressible and sub-sonic compressible solvers except those
providing implicit and tensorial porosity support. The approach will be
extended to cover these solvers and options in the future.
Note: the extrapolated pressure boundary condition is experimental and
requires further testing to assess the range of applicability,
stability, accuracy etc.
Henry G. Weller
CFD Direct Ltd.
so that the specification of the name and dimensions are optional in property dictionaries.
Update tutorials so that the name of the dimensionedScalar property is
no longer duplicated but optional dimensions are still provided and are
checked on read.
LTS is selected by the ddt scheme e.g. in the
tutorials/multiphase/interFoam/ras/DTCHull case:
ddtSchemes
{
default localEuler rDeltaT;
}
LTSInterFoam is no longer needed now that interFoam includes LTS
support.
nLimiterIter: Number of iterations during limiter construction
3 (default) is sufficient for 3D simulations with a Courant number 0.5 or so
For larger Courant numbers larger values may be needed but this is
only relevant for IMULES and CMULES
smoothLimiter: Coefficient to smooth the limiter to avoid "diamond"
staggering patters seen in regions of low particle phase-fraction in
fluidised-bed simulations.
The default is 0 as it is not needed for all simulations.
A value of 0.1 is appropriate for fluidised-bed simulations.
The useful range is 0 -> 0.5.
Values larger than 0.5 may cause excessive smearing of the solution.
