- The bitSet class replaces the old PackedBoolList class.
The redesign provides better block-wise access and reduced method
calls. This helps both in cases where the bitSet may be relatively
sparse, and in cases where advantage of contiguous operations can be
made. This makes it easier to work with a bitSet as top-level object.
In addition to the previously available count() method to determine
if a bitSet is being used, now have simpler queries:
- all() - true if all bits in the addressable range are empty
- any() - true if any bits are set at all.
- none() - true if no bits are set.
These are faster than count() and allow early termination.
The new test() method tests the value of a single bit position and
returns a bool without any ambiguity caused by the return type
(like the get() method), nor the const/non-const access (like
operator[] has). The name corresponds to what std::bitset uses.
The new find_first(), find_last(), find_next() methods provide a faster
means of searching for bits that are set.
This can be especially useful when using a bitSet to control an
conditional:
OLD (with macro):
forAll(selected, celli)
{
if (selected[celli])
{
sumVol += mesh_.cellVolumes()[celli];
}
}
NEW (with const_iterator):
for (const label celli : selected)
{
sumVol += mesh_.cellVolumes()[celli];
}
or manually
for
(
label celli = selected.find_first();
celli != -1;
celli = selected.find_next()
)
{
sumVol += mesh_.cellVolumes()[celli];
}
- When marking up contiguous parts of a bitset, an interval can be
represented more efficiently as a labelRange of start/size.
For example,
OLD:
if (isA<processorPolyPatch>(pp))
{
forAll(pp, i)
{
ignoreFaces.set(i);
}
}
NEW:
if (isA<processorPolyPatch>(pp))
{
ignoreFaces.set(pp.range());
}
- eliminate iterators from PackedList since they were unused, had
lower performance than direct access and added unneeded complexity.
- eliminate auto-vivify for the PackedList '[] operator.
The set() method provides any required auto-vivification and
removing this ability from the '[]' operator allows for a lower
when accessing the values. Replaced the previous cascade of iterators
with simpler reference class.
PackedBoolList:
- (temporarily) eliminate logic and addition operators since
these contained partially unclear semantics.
- the new test() method tests the value of a single bit position and
returns a bool without any ambiguity caused by the return type
(like the get() method), nor the const/non-const access (like
operator[] has). The name corresponds to what std::bitset uses.
- more consistent use of PackedBoolList test(), set(), unset() methods
for fewer operation and clearer code. Eg,
if (list.test(index)) ... | if (list[index]) ...
if (!list.test(index)) ... | if (list[index] == 0u) ...
list.set(index); | list[index] = 1u;
list.unset(index); | list[index] = 0u;
- deleted the operator=(const labelUList&) and replaced with a setMany()
method for more clarity about the intended operation and to avoid any
potential inadvertent behaviour.
- relocated ListAppendEqOp and ListUniqueEqOp to ListOps::appendEqOp
and ListOps::UniqueEqOp, respectively for better code isolation and
documentation of purpose.
- relocated setValues to ListOps::setValue() with many more
alternative selectors possible
- relocated createWithValues to ListOps::createWithValue
for better code isolation. The default initialization value is itself
now a default parameter, which allow for less typing.
Negative indices in the locations to set are now silently ignored,
which makes it possible to use an oldToNew mapping that includes
negative indices.
- additional ListOps::createWithValue taking a single position to set,
available both in copy assign and move assign versions.
Since a negative index is ignored, it is possible to combine with
the output of List::find() etc.
STYLE: changes for PackedList
- code simplication in the PackedList iterators, including dropping
the unused operator() on iterators, which is not available in plain
list versions either.
- improved sizing for PackedBoolList creation from a labelUList.
ENH: additional List constructors, for handling single element list.
- can assist in reducing constructor ambiguity, but can also helps
memory optimization when creating a single element list.
For example,
labelListList labels(one(), identity(mesh.nFaces()));
- The unset() method never auto-vivifies, whereas the set() method
always auto-vivifies. In the case where set() is called with a zero
for its argument - eg, set(index, 0) - this should behave
identically to an unset() and not auto-vivify out-of-range entries.
- it was possible to create a PackedList::iterator from a
PackedList::const_iterator and violate const-ness
- added HashTable::printInfo for emitting some information
- changed default table sizes from 100 -> 128 in preparation for future
2^n table sizes
- much better performance on empty tables (4-6x speedup), neutral
performance change on filled tables. Since tableSize_ is non-zero when
nElmts_ is, there is no modulus zero problem.
- dropped auto-vivification for now (performance issue), but reworked to
allow easy reinstatement
- derived both iterator and const_iterator from iteratorBase and use
iteratorBase as our proxy for non-const access to the list elements.
This allows properly chaining assignments:
list[1] = list[2];
list[1] = list[2] = 10;
- assigning iterators from iteratorBase or other iterators works:
iterator iter = list[20];
- made template parameter nBits=1 the default
- the bit counting is relatively fast:
under 0.2 seconds for 1M bits counted 1000 times
- trim()'ing the final zero elements tested for a few cases,
but might need more attention
- added Mattijs' speed tests
- optimized resize() and assignment operators to avoid set() method
- add const_iterator and re-did the proxy handling.
Reading/writing by looping across iterators is still somewhat slow, but
might be acceptable.
