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CHANGELOG

2.0.0

Date: 2015-05-09

  • Rewrite the parser engine. A few comments:

    The new code base uses C++11 to do more work in much fewer lines of code. The number of lines of code has decreased from about 1600 to 900 while at the same time increasing the amount of guiding comments.

    Previously, the parser code was essentially a hard-to-grap state machine (which b.t.w. could also have been implemented using only flex). This has been remedied. The code complexity has decreased by a lot and the process is severed into distinct parsing phases. This makes the code a lot easier to understand and modify.

    Downside: the code base is now fully dependent on C++11 which requires a recent compiler.

  • Remove some arbitrary restrictions in the language:

    • You can now use the shorthand notation 'A / B,C / D' to define markov chain with a link being a list of variables. The same limitation was overcome for the function-of syntax 'A:B' and the mutual independence statement 'A.B.C'.
    • You can now use inequalities as constraints
    • You can now use information expressions with arbitrary constants such as 'H(X) >= 1'. This is probably not very useful, but then again, there was no real reason not to allow it (or I didn't think of it, yet).

  • Don't not create temporary files anymore. Flex supports parsing in-memory data which is a clear winner compared to needless filesystem access.

  • use the lexer to split the input stream into tokens.

    Previously, the lexer was only used to do some obscur preprocessing the purpose of which is still completely unclear to me. In fact, I find it likely that this separate usage of the lexer could lead to inconsistent behaviour in some cases.

  • Variable names cannot contain white spaces any longer. This notation is now treated as a syntax error.

    In fact, in the face of the grammar definition, I believe this was an unintended side effect the hand-written yylex function just stripping away all whitespace. For example, 'H(X Y)' would be equivalent to 'H(XY)' but not to 'H(X,Y)', while their was a grammar rule trying to achieve the inverse.

  • Always perform stack unwinding in the main function

  • Slightly improve behaviour in the face of some errors

  • I am currently missing (at least?) one optimization that was present in Xitip: collapsing sets of variables that only appear together.

1.1.0

Date: 2015-04-18

  • Port to GLPK
  • Fix behaviour when checking for basic information measure (the mis-feature was inherited from Xitip)
  • obsessive style fixes
  • Reenable 'A:B' syntax (was broken due to my ignorance)

1.0.0 (now Citip)

Date: 2015-04-01

  • Replace the GTK frontend by a simple CLI.
  • Thus eliminate build time and run time dependencies on GTK, etc.
  • Start a proper README

Xitip (unspecified version)

Date: 2008-07-03

This is the version of Xitip as could be downloaded in a .tar.gz archive from their website in early 2015.

Unfortunately, I couldn't get into contact with any of the Xitip project authors (3 dead emails!), so I don't have access to their version history nor development branches or version number.

The release date guess (03 July 2008) is based on the most recent mtime among the extracted source files.

I excluded the binary and temporary files and the .svn metadata folder contained in the upstream tarball for obvious reasons.

Furthermore, I excluded the qsopt files. These should be downloaded by the user separately (which is on 64bit distributions necessary anyway). Though, the main reason not to include these files are the license issues.