- set() was silently deprecated in favour of reset() FEB-2018
since the original additional check for overwriting an existing
pointer was never used. The reset(...) name is more consistent
with unique_ptr, tmp etc.
Now emit deprecations for set().
- use direct test for autoPtr, tmp instead of valid() method.
More consistent with unique_ptr etc.
STYLE: eliminate redundant ptr() use on cloned quantities
- improves flexibility. Can tag a tmp as allowing non-const access to
the reference and skip additional const_cast in following code. For
example,
tmp<volScalarField> tfld(nullptr);
auto* ptr = getObjectPtr<volScalarField>("field");
if (ptr)
{
tfld.ref(*ptr);
}
else
{
tfld.reset(volScalarField::New(...));
}
auto& fld = tfld.ref();
ENH: renamed tmpNrc to refPtr
- the name 'refPtr' (reference|pointer) should be easier to remember
than tmpNrc (tmp, but non-ref-counted).
- provide tmpNrc typedef and header for code compatibility
NOTE
- in some places refPtr and tmp can be used instead of a
std::reference_wrapper for handling external references.
Unlike std::reference_wrapper, it can be default constructed
(holding nothing), whereas reference_wrapper may need a dummy
reference. However, the lifetime extension of references _may_ be
better with reference_wrapper.
- previously this was marked as '= delete' for consistency with
assignment from an empty pointer being a runtime error.
However, these can be considered semantically different and it makes
sense to permit this as equivalent to reset(nullptr).
This change does not break existing code since the operator was
previously unavailable (deleted).
STYLE: refactor tmp operator=(T*)
- delegate to reset() after initial checks
- Previously considered to be valid() if it was any reference
(null or non-null) or a non-null pointer.
This appears to be a holdover from old code (pre-2015) where
reinterpret_cast<..>(0) was used instead of the NullObject.
A reference via a null pointer isn't really possible anywhere. Even
for things like labelList::null(), they now use the NullObject,
which has a non-zero memory location.
- now simply check for a non-zero memory address. Regardless of
pointer or referenced object.
- combine reset() methods by adding a default parameter
- improve top-level visibility of empty/valid/get methods for symmetry
symmetry with autoPtr, future adjustment
- improves similarity to autoPtr. Simplifies coding.
Example,
tmp<volScalarField> tfield;
// sometime later...
tfield.reset
(
volScalarField::New("myfield", mesh, dimensionedScalar(Zero))
);
- as per tmp, disallow tmpNrc assignment from literal nullptr
- as per autoPtr, allow explicit test as bool (same as valid).
- similar to autoPtr and unique_ptr. Returns the pointer value without
any checks. This provides a simple way for use to use either
an autoPtr or a tmp for local memory management without accidentally
stealing the pointer.
Eg,
volVectorField* ptr;
tmp<volVectorField> tempField;
if (someField.valid())
{
ptr = someField.get();
}
else
{
tempField.reset(new volVectorField(....));
ptr = tmpField.get();
}
const volVectorField& withField = *ptr;
STYLE: make more tmp methods noexcept
Improvements to existing functionality
--------------------------------------
- MPI is initialised without thread support if it is not needed e.g. uncollated
- Use native c++11 threading; avoids problem with static destruction order.
- etc/cellModels now only read if needed.
- etc/controlDict can now be read from the environment variable FOAM_CONTROLDICT
- Uniform files (e.g. '0/uniform/time') are now read only once on the master only
(with the masterUncollated or collated file handlers)
- collated format writes to 'processorsNNN' instead of 'processors'. The file
format is unchanged.
- Thread buffer and file buffer size are no longer limited to 2Gb.
The global controlDict file contains parameters for file handling. Under some
circumstances, e.g. running in parallel on a system without NFS, the user may
need to set some parameters, e.g. fileHandler, before the global controlDict
file is read from file. To support this, OpenFOAM now allows the global
controlDict to be read as a string set to the FOAM_CONTROLDICT environment
variable.
The FOAM_CONTROLDICT environment variable can be set to the content the global
controlDict file, e.g. from a sh/bash shell:
export FOAM_CONTROLDICT=$(foamDictionary $FOAM_ETC/controlDict)
FOAM_CONTROLDICT can then be passed to mpirun using the -x option, e.g.:
mpirun -np 2 -x FOAM_CONTROLDICT simpleFoam -parallel
Note that while this avoids the need for NFS to read the OpenFOAM configuration
the executable still needs to load shared libraries which must either be copied
locally or available via NFS or equivalent.
New: Multiple IO ranks
----------------------
The masterUncollated and collated fileHandlers can now use multiple ranks for
writing e.g.:
mpirun -np 6 simpleFoam -parallel -ioRanks '(0 3)'
In this example ranks 0 ('processor0') and 3 ('processor3') now handle all the
I/O. Rank 0 handles 0,1,2 and rank 3 handles 3,4,5. The set of IO ranks should always
include 0 as first element and be sorted in increasing order.
The collated fileHandler uses the directory naming processorsNNN_XXX-YYY where
NNN is the total number of processors and XXX and YYY are first and last
processor in the rank, e.g. in above example the directories would be
processors6_0-2
processors6_3-5
and each of the collated files in these contains data of the local ranks
only. The same naming also applies when e.g. running decomposePar:
decomposePar -fileHandler collated -ioRanks '(0 3)'
New: Distributed data
---------------------
The individual root directories can be placed on different hosts with different
paths if necessary. In the current framework it is necessary to specify the
root per slave process but this has been simplified with the option of specifying
the root per host with the -hostRoots command line option:
mpirun -np 6 simpleFoam -parallel -ioRanks '(0 3)' \
-hostRoots '("machineA" "/tmp/" "machineB" "/tmp")'
The hostRoots option is followed by a list of machine name + root directory, the
machine name can contain regular expressions.
New: hostCollated
-----------------
The new hostCollated fileHandler automatically sets the 'ioRanks' according to
the host name with the lowest rank e.g. to run simpleFoam on 6 processors with
ranks 0-2 on machineA and ranks 3-5 on machineB with the machines specified in
the hostfile:
mpirun -np 6 --hostfile hostfile simpleFoam -parallel -fileHandler hostCollated
This is equivalent to
mpirun -np 6 --hostfile hostfile simpleFoam -parallel -fileHandler collated -ioRanks '(0 3)'
This example will write directories:
processors6_0-2/
processors6_3-5/
A typical example would use distributed data e.g. no two nodes, machineA and
machineB, each with three processes:
decomposePar -fileHandler collated -case cavity
# Copy case (constant/*, system/*, processors6/) to master:
rsync -a cavity machineA:/tmp/
# Create root on slave:
ssh machineB mkdir -p /tmp/cavity
# Run
mpirun --hostfile hostfile icoFoam \
-case /tmp/cavity -parallel -fileHandler hostCollated \
-hostRoots '("machineA" "/tmp" "machineB" "/tmp")'
Contributed by Mattijs Janssens
Improve alignment of its behaviour with std::shared_ptr
- element_type typedef
- swap, reset methods
* additional reference access methods:
cref()
returns a const reference, synonymous with operator().
This provides a more verbose alternative to using the '()' operator
when that is desired.
Mnemonic: a const form of 'ref()'
constCast()
returns a non-const reference, regardless if the underlying object
itself is a managed pointer or a const object.
This is similar to ref(), but more permissive.
Mnemonic: const_cast<>
Using the constCast() method greatly reduces the amount of typing
and reading. And since the data type is already defined via the tmp
template parameter, the type deduction is automatically known.
Previously,
const tmp<volScalarField>& tfld;
const_cast<volScalarField&>(tfld()).rename("name");
volScalarField& fld = const_cast<volScalarField&>(tfld());
Now,
tfld.constCast().rename("name");
auto& fld = tfld.constCast();
--
BUG: attempts to move tmp value that may still be shared.
- old code simply checked isTmp() to decide if the contents could be
transfered. However, this means that the content of a shared tmp
would be removed, leaving other instances without content.
* movable() method checks that for a non-null temporary that is
unique (not shared).
