This file contains details of the changes in each new version of PRISM,
including development and beta versions. For a less detailed overview
of the main changes in each public release, see the file VERSIONS.txt.

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Version 3.3.1 (released 22/11/2009)
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Bug fixes:
- Building on new 64-bit Macs
- Simulator bug (crashes on min/max function)
- CTMC transient probs with MTBDD engine crash
- State/transition reward mix-up in parser
- Approximate verification of lower time-bounded properties for CTMCs

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Version 3.3 (released 29/10/2009)
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Bug fixes:
- Building on new Macs
- Copy+paste bug in GUI

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Version 3.3.beta2 (released 29/7/2009)
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Bug fixes:
- LTL model checking (svn: 112, 1132)
- Approximate model checking (svn: 1214)
- Building on new Macs (svn: 1103, 1105, 1349)

-----------------------------------------------------------------------------
Version 3.3.beta1 (released 20/5/2009) (svn: trunk rev 1066)
-----------------------------------------------------------------------------

* New language parser:
  - improved efficiency, especially on large/complex models
  - more accurate error reporting
* GUI model editor improvements:
  - error highlighting
  - line numbers
  - undo/redo feature
* Expanded property specification language
  - LTL (and PCTL*) now supported
  - arbitrary expressions allowed, e.g. 1-P=?[...]
  - support for weak until (W) and release (R) added
  - steady-state operators (S=?[...], R=?[S]) allowed for DTMCs
  - optional semicolons to terminate properties in properties files
* Modelling language changes:
  - cleaner notation for functions, e.g. mod(i,n), not func(mod,i,n)
  - function names can be renamed in module renaming
  - language strictness: updates (x'=...) must be parenthesised
  - ranges (x=1..3,5) no longer supported
  - added conversion tool for old models (etc/scripts/prism3to4)
* Other minor technical changes to language:
  - implication allowed in any expression (not just properties)
  - floor/ceil are now identifiers, not keywords
  - relational operators now have precedence over equality operators
  - better but slightly different parsing of problem cases like "F<=a b"
* Improvements to memory handling, especially in sparse/hybrid engines
* Updated JFreeChart library
* Multiple -const switches allowed at command-line
* Efficiency improvements to precomputation algorithms
* Added symmetry reduction functionality
* New -exportbsccs option 
* Initial state info for explicit import is now via -importlabels
* Added prism2html/prism2latex tools (in etc/scripts)
* Sparse/hybrid versions of instantaneous reward properties (R=?[I=k]) for DTMCs
* Easier viewing of model checking results in GUI
* Steady-state/transient probability computation for DTMCs

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Version 3.2.beta1 (released 25/2/2008) (svn: trunk rev 568)
-----------------------------------------------------------------------------

* Fix to allow building on Mac OS X v10.5 (Leopard)
* New option for displaying extra info during reachability (-extrareachinfo switch)
* Addition of some missing reward model checking algorithms
  - instantaneous reward properties (R=?[I=k]) for DTMCs/MDPs (MTBDD/sparse engines only)
  - cumulative reward properties (R=?[C<=k]) for DTMCs
  - sparse engine version of reach reward properties (R=?[F...]) for MDPs
* New option for displaying extra (MT)BDD info (-extraddinfo switch)
* Font increase/decrease feature in GUI
* Labels (for use in properties file) can be defined in the model file
* Properties files can use formulas from model file
* Partially correct property files can be loaded into the GUI
* New icon set and graphics
* New graph plotting engine using JFreeChart
* Prototype SBML-to-PRISM translator
* New option for -simpath feature: can enable/disable loop checking
* New option for -simpath feature: generation of multiple paths to find deadlock
* New "rows" option for matrix exports (-exportrows switch)
* Support for 64-bit architectures
* Addition of F and G operators to property language (eventually/globally)
* Redesign of the simulator GUI, plus new features:
  - ability to display cumulated time/rewards
  - new "Configure view" dialog
  - easier selection of next step (double click) 
* Resizeable experiment results table 
* Function "log" for use in expressions

-----------------------------------------------------------------------------
Version 3.1.1 (5/4/2007) (svn: derived from 3.1 tag)
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* Minor bug fixes:
  - bug in "New Graph" dialog which fails on Java 6
  - threading bug which can cause graph plotting to freeze
  - fix to possible failure of Windows launch scripts

-----------------------------------------------------------------------------
Version 3.1 (15/11/2006) (svn: derived from 3.1.beta1 tag)
-----------------------------------------------------------------------------

* No changes

-----------------------------------------------------------------------------
Version 3.1.beta1 (3/11/2006) (svn: trunk rev 116)
-----------------------------------------------------------------------------

* New installer for Windows binary
* Models can now have multiple (named) reward structures
* New -simpath switch for command-line generation of random paths with simulator
* Minor PRISM language improvements:
  - type keyword does not need to be first thing in model file
  - doubles in exponential form (1.4e-9) and unary minus (-1) allowed
* PRISM settings file now used by command-line version too
* Small GUI improvements
* New option to disable steady-state detection for CTMC transient analysis
* Bug fixes

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Version 3.0 (6/7/2006) (svn: trunk rev 55)
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* Bug fixes

-----------------------------------------------------------------------------
Version 3.0.beta1 (29/3/2006) (svn: trunk rev 45)
-----------------------------------------------------------------------------

* Changes to export functionality
  - transition matrix graph can be exported to a Dot file (-exporttransdot)
  - can export state/transition rewards
  - can export labels and their satisfying states
  - can export to stdout/log instead of a file
  - can export in MRMC format
  - improved support for Matlab format export
  - exported matrices now ordered by default (by row)
  - new/rearranged command-line switches
* Added new options to Model|View menu in GUI
* Additional checks when parsing models:
  - synchronous commands modifying globals
    (now disallowed, previously just advised against)
  - modification of local variables by another module
    (previously detected later at build-time)
* Improvements/changes to explicit import functionality:
  - -importstates understands Boolean variables now
  - -importinit option added
  - Default module variable (x) indexed from 0, not 1
* Non-convergence of iterative methods is an error, not a warning
* Changed layout of simulator transition table (4 -> 3 columns)
* Bugfixes
* Makefile improvements  

-----------------------------------------------------------------------------
Version 2.1.dev11.sim8 (3/3/2006)
-----------------------------------------------------------------------------

* Bug fix: computation of powers in simulator
* Bug fix: calculation of transition rewards from multiple actions
* Bug fixes: loop detection and deadlocks in simulator

-----------------------------------------------------------------------------
Version 2.1.dev11.sim7 (5/1/2006)
-----------------------------------------------------------------------------

* Bug fixes, tidying

-----------------------------------------------------------------------------
Version 2.1.dev11.sim6 (16/12/2005)
-----------------------------------------------------------------------------

* Merged with simulator branch
* Improved options management including saving of user settings

-----------------------------------------------------------------------------
Version 2.1.dev11 (5/12/2005)
-----------------------------------------------------------------------------

Changes:

* Bugfixes in GUI syntax highlighting, esp. for large model files
* Bugfix: out-of-range initial values banned

-----------------------------------------------------------------------------
Version 2.1.dev10 (21/10/2005)
-----------------------------------------------------------------------------

Changes:

* GUI syntax highlighting restructure and efficiency improvement
* Bugfix/tidy in GUI experiments, esp. with Booleans
* Bugfix/improvements in modulo operations
* Improvements to checks of probabilities/rates, e.g. for NaN
* Ability to disable checks of probabilities/rates

-----------------------------------------------------------------------------
Version 2.1.dev9 (27/05/2005)
-----------------------------------------------------------------------------

Changes:

* Tidied up simulator code/stubs
* Graphical model editor disabled

-----------------------------------------------------------------------------
Version 2.1.dev8 (11/05/2005)
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Changes:

* Can now be built on OS X
* Makefile improvements including better OS detection
* Bug fix improving efficiency of BSCC computation
* Improved reporting of multiple missing constants

-----------------------------------------------------------------------------
Version 2.1.dev7 (22/2/2005)
-----------------------------------------------------------------------------

Changes:

* Graphical model editor (temporarily?) enabled
* Addition of simulator code and stubs
* Tweaked main Makefile: stops after first error

-----------------------------------------------------------------------------
Version 2.1.dev6 (18/2/2005)
-----------------------------------------------------------------------------

Changes:

* Bug fix - alphabet for default synchronisation is now derived syntactically
* Updates to some APMC code

-----------------------------------------------------------------------------
Version 2.1.dev5 (11/2/2005)
-----------------------------------------------------------------------------

Partially completed changes:

* PRISM Preprocessor
* Improved hybrid GS
* Improved syntax highlighting

Changes:

* Max memory for Java VM modifiable via PRISM_JAVAMAXMEM environment variable
* Reorganisation of Linux/Solaris launch scripts
* New notation for functions in PRISM language: func(f,x,y)
* New built-in functions in PRISM language (new notation only) - power(pow), modulo(mod)
* Upgrade to newest version of CUDD (2.4.0)
* GUI supports multi-line comments for properties
* Command-line override of model type allowed (-dtmc,-ctmc,-mdp switches)
* Tidy up of output generated by filters in P/S operators
* Added built-in label "deadlock", true in states where deadlocks fixed by PRISM
* Conditional evaluation operator now allows bracketless nesting, e.g. a?b:c?d:e
* Bug fixes

-----------------------------------------------------------------------------
Version 2.1.dev4 (21/1/2005)
-----------------------------------------------------------------------------

Changes:

* New syntax for transition rewards (within rewards construct)
* Bugfix in Prob1A precomputation algorithm
* Bugfix: disappearing "{min}"/"{max}" from P/R operators
* Numerous improvements to graph plotting tool
  - Export of graphs to Matlab
  - Import/export of graphs from/to XML
  - Enhanced scale behaviour/options
  - Improved editing of series properties/data
  - Various bug fixes
* More thorough checks of commands during model construction
  - each command must define transitions for all states satisfying guard

-----------------------------------------------------------------------------
Version 2.1.dev3 (17/11/2004)
-----------------------------------------------------------------------------

Partially completed changes:

* Graphical model editor significantly improved (but disabled for now)

Changes:

* Support for import of (explicit) transition matrix and state space
  (command-line only, via -importtrans/-importstates switches (and -dtmc,-ctmc,-mdp))
* Improvements to graph plotting functionality
* Log in GUI now operates with a limited size buffer to avoid out-of-memory problems


-----------------------------------------------------------------------------
Version 2.1.dev2 (20/10/2004)
-----------------------------------------------------------------------------

Partially completed changes:

* Support for costs/rewards
  - DTMC: R[F] H/S/M
  - MDP: R[F] M ok, H partial
  - CTMC: R[F] H/S/M, R[I=t] H/S/M, R[S] H/S/M, C[<=t] H/S/M

Changes:

* Added facility to compute transient probabilities


-----------------------------------------------------------------------------
Version 2.1.dev1 (7/10/2004)
-----------------------------------------------------------------------------

Partially completed changes:

* Support for costs/rewards
* Checks during model construction that rates are non-negative and probabilities sum to one

Changes:

* Multiple initial states init...endinit
* Support for displaying min/max of a range of probabilities using {} notation
* New "compact" storage schemes (distinct values only) added to sparse/hybrid engines
* Sparse storage schemes now use (more compact) counts instead of start indices for rows/cols
* True Gauss-Seidel algorithm for hybrid engine
* New switches (-pgs, -psor, -bpgs, -bpsor) to access hybrid "psuedo" methods
* Language modification: updates can be "true", i.e. no variables change
* Added conditional evaluation operator (cond ? then : else) to PRISM language


-----------------------------------------------------------------------------
Version 2.1 (released 8/9/2004)
-----------------------------------------------------------------------------

Changes:

* Now possible to build/run PRISM on Windows
* Compilation/installation procedures slightly simplified
* Splash screen on load


-----------------------------------------------------------------------------
Version 2.0 (released 17/3/2004)
-----------------------------------------------------------------------------

Changes:

* Completely new graphical user interface, including:
  - Text editor for PRISM language
  - Automated results collection/graph plotting
  
* Enhancements to PRISM language:
  - Types (ints, doubles and booleans) and type checking added
  - Probabilities/rates can now be expressions
  - Variable ranges/initial values can now be expressions
  - Constant/formula definitions can be expressions (including in terms of each other)
  - Process algebra style definitions allowed for MDPs too (via "system" construct)
  
* Enhancements to property specifications:
  - Probability/time bounds in PCTL/CSL properties can now be expressions
  - Use of constants now permitted: both those from the model and newly declared ones
  - Added "init" keyword to PCTL/CSL (atomic proposition true only in initial state)
  - Can define and reuse "labels" (atomic propositions) (like formulas in model files)
  - Can write properties of the form "P=?[...]" which return the actual probability
  
 * Additional features:
  - Automatic handling of multiple model checking computations,
    e.g. check "P~p[true U<=k error]" for k=1..100
  - Added -exportstates switch, exports reachable states to text file
  - Added -nobscc switch for optional bypass of BSCC computation
  - Added explicit versions of export options (including first export option for MDPs)
  - Export options can now be used in conjunction with each other and with model checking
  - Added -version switch to display version
  
* Efficiency improvements
  - Improved heuristics for hybrid engine (sb/sbmax/gsl switches -> sbmax/sbl/gsmax/gsl)
  - More efficient construction process for unstructured models
  - General restructuring/improvements to model construction process implementation
  
* Miscellaneous
  - Various bug fixes
  - Fairness (for MDP model checking) now OFF by default (used to be ON)


-----------------------------------------------------------------------------
Version 1.3.1 (released 20/2/2003)
-----------------------------------------------------------------------------

Changes:

* Bug fixes in model construction code


-----------------------------------------------------------------------------
Version 1.3 (released 10/2/2003)
-----------------------------------------------------------------------------

Changes:

* Steady-state probability computation improved to include strongly connected component (SCC) computation
* Extended support for CSL time-bounded until operator to include arbitrary intervals
* More flexible parallel composition options in the PRISM language (for DTMCs and CTMCs)
* Added option to import PEPA process algebra descriptions as models
* Improved range of numerical methods: (Backwards) Gauss-Seidel and (Backwards) SOR (plus variants for hybrid engine)
* Added -pctl/-csl switches to allow command line specification of properties
* Improved handling of deadlock states: can add self-loops to these states automatically (e.g. -fixdl switch)
* Steady-state probabilities are no longer automatically computed for CTMCs: use the -ss switch
* Addition of {} operator to PCTL/CSL formulas to support printing of probabilities
* Resolved problem with PRISM language syntax: updates must now be parenthesised
* Default value for maximum number of iterations reduced from 500,000 to (more sensible) 10,000
* Added switches to control CUDD behaviour (-cuddmaxmem, -cuddepsilon)
* Additional example files
* Numerous bug fixes
* Now released under the GPL license


-----------------------------------------------------------------------------
Version 1.2 (released 17/9/2001)
-----------------------------------------------------------------------------

First public release

