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  • Mark OLESEN's avatar
    ENH: new bitSet class and improved PackedList class (closes #751) · bac943e6
    Mark OLESEN authored
    - 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());
          }
    bac943e6