CHANGES IN bit VERSION 1.1.2

USER VISIBLE CHANGES

    o The package now has a namespace



    CHANGES IN bit VERSION 1.1.1

USER VISIBLE CHANGES

    o Function 'chunk' has been made generic, the default method
      provides the previous behavior.

    o New method to increase length of bitwhich objects.

    o Added further coercion methods.
      provides the previous behavior.


BUG FIXES
    o as.bitwhich.ri now generates correct negative subscripts.



    CHANGES IN bit VERSION 1.1.0


NEW FEATURES

    o New class 'bitwhich' stores subscript positions in most efficient way:
      TRUE for all()==TRUE, FALSE for !any()==TRUE. otherwise positive or
      negative subscripts, whatever needs less RAM. Coercion functions and 
      logical operators are available, the latter being efficient for very
      asymetric (skewed) distributions: selecting or exlcuding small factions
      of the data.
    
    o New class 'ri' (range index) allows to select ranges of positions for 
      chunked processing: all three classes 'bit', 'bitwhich' and 'ri' can be 
      used for subsetting 'ff' objects (ff-2.1.0 and higher).
    
    o New c() method for 'bit' and 'bitwhich' objects which behaves like 
      c(logical).

    o The bit methods sum(), any(), all(), min(), max(), range(), summary() 
      and which() now support a range argument that allows to restrict the 
      range of evaluation for chunked processing.

    o New utilities for chunked processing: bbatch, repfromto, chunk, vecseq.


USER VISIBLE CHANGES

    o reducing length of bit objects will now set hidden bits to FALSE, 
      such that subsequent length increase behaves consistent with bit
      objects that had never been reduced in length: new bits are FALSE

    o 'which' is no longer turned into a generic. Use 'bitwhich' instead, 
      or, 'as.which' if you need strictly positive subscripts. 
      
    o 'which.bit' has been renamed to 'as.which.bit'. It no longer has 
      parameter 'negative' and always returns positive subscripts (wish of 
      Stavros Macrakis). It now has second parameter 'range' in order to return
      subscripts for chunked processing (note that the bitwhich representation 
      is not suitable for chunked processing). In order to facilitate coercion, 
      the return vector of 'as.which' now has class 'which'.
      
    o the internal structure of a bit object has been changed to align with ff 
      ram objects: the bitlength of a bit object is no longer stored in 
      attr(bit, "n"), instead in attr(attr(bit, "physical"), "Length"),
      which is accessible via physical(bit)$Length, but should be accessed
      usually via length(bit). 

    o the semantics of 'min', 'max' and 'range' have been changed. They now 
      refer to the positions of TRUE in the bit vector (and thus are consistent
      with bitwhich rather than with logical. The 'summary' method now returns 
      four elements c("FALSE"=, "TRUE"=, "Min."=, "Max."=).


BUG FIXES

    o which.bit no longer returns integer() for a bit vector that has all TRUE


KNOWN PROBLEMS / TODOs

    o NAs are mapped to TRUE in 'bit' and to FALSE in 'ff' booleans. Might be aligned 
      in a future release. Don't use bit if you have NAs - or map NAs explicitely.