CHANGELOG.md

Changelog

This changelog lists only the most important changes. Smaller (bug)fixes as well as non-mature features are not part of the changelog. The releases of major and minor versions contain an overview of changes since the last major/minor update.

Version 1.9.x

Version 1.9.0 (2024/08)

• Improved expected visiting times (EVTs) and steady state distribution computations.
• Support for interval-based models.
• Robust VI.
• Significantly improved compilation times.
• Support for logarithm expressions in PRISM and JANI.
• Support for sin and cos operators, and PI and Euler constants in JANI parser.
• Extraction of schedulers for minimal expected total rewards.
• More efficient MEC and SCC decompositions.
• Revised LP encoding for multi-objective verification under simple strategies.
• Added CLI option --permute to re-order the states after building.
• Added CLI option --build:state limit <number> to limit the number of explored states.
• Print all linked libraries when using --version.
• Removed support for HyPro and Cuda.
• Moved gamebased-ar to own library.
• Various bug fixes.
• storm-conv: Removed option --stdout.
• storm-dft: Fixes and improvements for DFT symmetries and DFT simulation.
• storm-pars: Completely reworked the command-line interface (and partially the C++ API).
• storm-pars: "Time travelling" optimization.
• storm-pgcl: Removed the library.
• Developer: Require at least CMake version 3.15.
• Developer: Moved storm-config.h.in into src directory.
• Developer: Use various Dockerfiles in CI.
• Developer: Revised includes and use pre-compiled headers.
• Developer: Fixed various compiler warnings.

Version 1.8.x

Version 1.8.1 (2023/06)

• Workaround for issue with Boost >= 1.81

Version 1.8.0 (2023/05)

• Revised implementation of value iteration algorithms and its variants, fixing a bug in the optimistic value iteration heuristic.
• Experimental support for compiling on Apple Silicon
• Added SoPlex as a possible LP solver
• Upgraded shipped version of sylvan
• Upgraded repo / version for carl (for polynomials), requires carl-storm in at least version 14.23.
• Removed support for just-in-time compilation (JIT). If the JIT engine is needed, use Storm version 1.7.0.
• storm-dft: better modularization: improved algorithm for finding independent modules and revised the DFT analysis via modularization.
• storm-dft: added checks whether a given DFT is well-formed and conventional.
• storm-pomdp: streamlined implementation for quantitative analysis
• storm-pomdp: added clipping for POMDP under-approximation
• storm-pomdp: added API for interactive exploration of belief MDPs
• Developer: Introduced forward declarations (in their own headers), in particular for storm::RationalNumber, storm::RationalFunction, and storm::json
• Developer: LpSolver interface now supports RawMode (to avoid overhead of storm::expression) and indicator constraints

Version 1.7.x

Version 1.7.0 (2022/07)

• Fixed a bug in LP-based MDP model checking.
• DRN Parser is now more robust, e.g., it does no longer depend on tabs.
• PRISM Parser: Modulo with negative numbers is now consistent with Prism.
• Added lexicographic multi-objective model checking. Use --lex in the command line interface when specifying a multi(...) property.
• Fix handling duplicate entries in the sparse matrix builder.
• Added support for step-bounded until formulas in LTL.
• Added Dockerfile.
• API: Applying a fully defined deterministic memoryless scheduler to an MDP yields a DTMC.
• storm-dft: Use dedicated namespace storm::dft.
• storm-dft: Added support (parsing, export, BDD analysis) for additional BE failure distributions (Erlang, log-normal, Weibull, constant probability).
• storm-dft: Added instantiator for parametric DFT.
• Developer: Storm is now built in C++17 mode.
• Developer: Added support for automatic code formatting for storm-dft.

Version 1.6.x

Version 1.6.4 (2022/01)

• Added support for model checking LTL properties in the sparse (and dd-to-sparse) engine. Requires building with Spot or an external LTL to deterministic automaton converter (using option --ltl2datool).
• Added cmake options STORM_USE_SPOT_SYSTEM and STORM_USE_SPOT_SHIPPED to facilitate building Storm with Spot.
• Improved parsing of formulas in PRISM-style syntax.
• Added export of schedulers that use memory (in particular optimizing schedulers for LTL properties)
• Added support for PRISM models that use unbounded integer variables.
• Added support for nested arrays in JANI.
• Added --location-elimination that can be applied to Jani DTMC models to reduce the size of the resulting Markov models, see here.
• Added an export of check results to json. Use --exportresult in the command line interface.
• Added --exportbuilt option that exports the built model in various formats. Deprecates --io:exportexplicit, --io:exportdd and --io:exportdot
• Added export of built model in .json. which can be used to debug and explore the model.
• Added computation of steady state probabilities for DTMC/CTMC in the sparse engine. Use --steadystate in the command line interface.
• Added computation of the expected number of times each state in a DTMC/CTMC is visited (sparse engine). Use --expvisittimes in the command line interface.
• Implemented parsing and model building of Stochastic multiplayer games (SMGs) in the PRISM language. No model checking implemented (yet).
• API: Simulation of prism-models
• API: Model-builder takes a callback function to prevent extension of particular actions, prism-to-explicit mapping can be exported
• API: Export of dice-formatted expressions
• Prism-language/explicit builder: Allow action names in commands writing to global variables if these (clearly) do not conflict with assignments of synchronizing commads.
• Prism-language: n-ary predicates are supported (e.g., ExactlyOneOf)
• Added support for continuous integration with Github Actions.
• storm-pars: Exploit monotonicity for computing extremal values and parameter space partitioning.
• storm-dft: Support for analysis of static fault trees via BDDs (Flag --bdd). In particular, efficient computation of multiple time bounds was added and support for several importance measures (Argument --importance).
• storm-dft: Computation of minimal cut sets for static fault trees (Flag --mcs).
• storm-dft: Improved modularisation for DFT by exploiting SFT analysis via BDDs.
• storm-dft: Fixed don't care propagation for shared SPAREs which resulted in wrong results.
• Developer: Added support for automatic code formatting and corresponding CI workflow.

Version 1.6.3 (2020/11)

• Added support for multi-objective model checking of long-run average objectives including mixtures with other kinds of objectives.
• Added support for generating optimal schedulers for globally formulae.
• Simulator supports exact arithmetic.
• Added switch --no-simplify to disable simplification of PRISM programs (which sometimes costs a bit of time on extremely large inputs).
• Fixed issues with JANI inputs concerning .
  • transient variable expressions in properties,
  • constants in properties, and
  • integer variables with either only an upper or only a lower bound.
• storm-pomdp: States can be labelled with values for observable predicates.
• storm-pomdp: (Only API) Track state estimates.
• storm-pomdp: (Only API) Reduce computation of state estimates to computation on unrolled MDP.

Version 1.6.2 (2020/09)

• Prism program simplification improved.
• Revamped implementation of long-run-average algorithms, including scheduler export for LRA properties on Markov automata.
• Support for step-bounded properties of the form ... [F[x,y] ... ] for DTMCs and MDPs (sparse engine).
• Renamed portfolio engine to automatic
• storm-dft: Fix for relevant events when using symmetry reduction.
• storm-pomdp: Fix for --transformsimple and --transformbinary when used with until formulae.
• storm-pomdp: POMDPs can be parametric as well.

Version 1.6.0 (2020/06)

• Changed default Dd library from cudd to sylvan. The Dd library can be changed back to cudd using the command line switch --ddlib.
• Scheduler export: Properly handle models with end components. Added export in .json format.
• CMake: Search for Gurobi prefers new versions.
• CMake: We no longer ship xerces-c. If xerces-c is not found on the system, storm-gspn will not be able to parse xml-based GSPN formats.
• CMake: Added option STORM_LOAD_QVBS to automatically download the quantitative verification benchmark set.
• Eigen library: The source code of Eigen is no longer included but downloaded from an external repository instead. Incremented Eigen version to 3.3.7 which fixes a compilation issue with recent XCode versions.
• Tests: Enabled tests for permissive schedulers.
• storm-counterexamples: fix when computing multiple counterexamples in debug mode.
• storm-dft: Renamed setting --show-dft-stats to dft-statistics and added approximation information to statistics.
• storm-pomdp: Implemented approximation algorithms that explore (a discritization of) the belief MDP, allowing to compute safe lower- and upper bounds for a given property.
• storm-pomdp: Implemented almost-sure reachability computations: graph-based, one-shot SAT-based, and iterative SAT-based.
• `storm-pomdp': Various changes such that transformation to pMCs is now again supported (and improved).
• Fixed several compiler warnings.

Version 1.5.x

Version 1.5.1 (2020/03)

• Jani models are now parsed using exact arithmetic.

Version 1.5.0 (2020/03)

• Added portfolio engine which picks a good engine (among other settings) based on features of the symbolic input.
• Abort of Storm (via timeout or CTRL+C for example) is now gracefully handled. After an abort signal the program waits some seconds to output the result computed so far and terminates afterwards. A second signal immediately terminates the program.
• Setting --engine dd-to-sparse --bisimulation now triggers extracting the sparse bisimulation quotient.
• JIT model building is now invoked via --engine jit (instead of --jit).
• DRN: support import of choice labelling.
• Added option --build:buildchoiceorig to build a model (PRISM or JANI) with choice origins (which are exported with, e.g. --exportscheduler).
• Implemented optimistic value iteration for sound computations and set it as new default in --sound mode.
• Time bounded properties for Markov automata are now computed with relative precision. Use --absolute for the previous behavior.
• Apply the maximum progress assumption while building a Markov automaton with one of the symbolic engines.
• Added option --build:nomaxprog to disable applying the maximum progress assumption during model building (for Markov Automata).
• Added hybrid engine for Markov Automata.
• Improved performance of the Unif+ algorithm (used for time-bounded properties on Markov Automata).
• Various performance improvements for model building with the sparse engine.
• storm-dft: Symmetry reduction is now enabled by default and can be disabled via --nosymmetryreduction.
• storm-pomdp: Only accept POMDPs that are canonical.
• storm-pomdp: Prism language extended with observable expressions.
• storm-pomdp: Various fixes that prevented usage.
• Several bug fixes.

Version 1.4.x

Version 1.4.1 (2019/12)

• Implemented long run average (LRA) computation for DTMCs/CTMCs via value iteration and via gain/bias equations.
• Added several LRA related settings in a new settings module. Note that --minmax:lramethod has been replaced by --lra:nondetmethod.

Version 1.4.0 (2019/11)

• Added support for multi-dimensional quantile queries.
• Added support for multi-objective model checking under pure (deterministic) schedulers with bounded memory using --purescheds.
• Allow to quickly check a benchmark from the Quantitative Verification Benchmark Set using the --qvbs option.
• Added script resources/examples/download_qvbs.sh to download the QVBS.
• If an option is unknown, Storm now suggests similar option names.
• Flagged several options as 'advanced' to clean up the --help-message. Use --help all to display a complete list of options.
• Support for parsing of exact time bounds for properties, e.g., P=? [F=27 "goal"].
• Export of optimal schedulers when checking MDPs with the sparse engine (experimental). Use --exportscheduler <filename>.
• PRISM language: Support for the new round operator.
• PRISM language: Improved error messages of the parser.
• JANI: Allow bounded types for constants.
• JANI: Support for non-trivial reward accumulations.
• JANI: Fixed support for reward expressions over non-transient variables.
• DRN: Added support for exact parsing and action-based rewards.
• DRN: Support for placeholder variables which allows to parse recurring rational functions only once.
• Fixed sparse bisimulation of MDPs (which failed if all non-absorbing states in the quotient are initial).
• Support for export of MTBDDs from Storm.
• Support for k-shortest path counterexamples (arguments -cex --cextype shortestpath)
• New settings module transformation for Markov chain transformations. Use --help transformation to get a list of available transformations.
• Support for eliminating chains of Non-Markovian states in MAs via --eliminate-chains.
• Export to dot format allows for maximal line width in states (argument --dot-maxwidth <width>)
• storm-conv can now apply transformations on a prism file.
• storm-pars: Enabled building, bisimulation and analysis of symbolic models.
• storm-dft: Support partial-order for state space generation.
• storm-dft: Compute lower and upper bounds for number of BE failures via SMT.
• storm-dft: Allow to set relevant events which are not set to Don't Care.
• storm-dft: Support for constant failed BEs. Use flag --uniquefailedbe to create a unique constant failed BE.
• storm-dft: Support for probabilistic BEs via PDEPs.
• Fixed linking with Mathsat on macOS.
• Fixed linking with IntelTBB for GCC.
• Fixed compilation for macOS Mojave and higher.
• Several bug fixes.

Version 1.3.x

Version 1.3.0 (2018/12)

• Slightly improved scheduler extraction
• Environments are now part of the c++ API
• Heavily extended JANI support, in particular:
  • arrays, functions, state-exit-rewards (all engines)
  • indexed assignments, complex reward expressions (sparse engine)
  • several jani-related bug fixes
• New binary storm-conv that handles conversions between model files
• New binary storm-pomdp that handles the translation of POMDPs to pMCs.
• Maximal progress assumption is now applied while building Markov Automata (sparse engine).
• Improved Unif+ implementation for Markov Automata, significantly reduced memory consumption.
• Added support for expected time properties for discrete time models
• Bug fix in the parser for DRN (MDPs and MAs might have been affected).
• storm-gspn: Improved .pnpro parser
• storm-gspn: Added support for single/infinite/k-server semantics for GSPNs given in the .pnpro format
• storm-gspn: Added option to set a global capacity for all places
• storm-gspn: Added option to include a set of standard properties when converting GSPNs to jani
• storm-pars: Added possibility to compute the extremal value within a given region using parameter lifting
• storm-dft: DFT translation to GSPN supports Don't Care propagation
• storm-dft: Support DFT analysis via transformation from DFT to GSPN to JANI
• storm-dft: Added SMT encoding for DFTs
• storm-dft: Improved Galileo and JSON parser
• Several bug fixes
• Storm uses the master14 branch of carl from now on

Comparison with Version 1.2.0 (details see below)

• Heavily extended JANI-support
• New binary storm-conv that handles conversion between model files
• New binary storm-pomdp that handles the translation of POMDPs to pMCs.
• storm-gspn improved
• Sound value iteration

Version 1.2.x

Version 1.2.3 (2018/07)

• Fix in version parsing

Version 1.2.2 (2018/07)

• Sound value iteration (SVI) for DTMCs and MDPs
• Topological solver for linear equation systems and MinMax equation systems (enabled by default)
• Added support for expected total rewards in the sparse engine
• By default, iteration-based solvers are no longer aborted after a given number of steps.
• Improved export for jani models
• A fix in parsing jani properties
• Several extensions to high-level counterexamples
• storm-parsers extracted to reduce linking time
• storm-counterexamples extracted to reduce linking time
• storm-dft: improvements in Galileo parser
• storm-dft: test cases for DFT analysis
• Improved Storm installation
• Several bug fixes

Version 1.2.1 (2018/02)

• Multi-dimensional reward bounded reachability properties for DTMCs.
• storm-dft: transformation of DFTs to GSPNs
• Several bug fixes

Version 1.2.0 (2017/12)

• C++ api changes: Building model takes BuilderOptions instead of extended list of Booleans, does not depend on settings anymore.
• storm-cli-utilities now contains cli related stuff, instead of storm-lib
• Symbolic (MT/BDD) bisimulation
• Fixed issue related to variable names that can not be used in Exprtk.
• DRN parser improved
• LP-based MDP model checking
• Sound (interval) value iteration
• Support for Multi-objective multi-dimensional reward bounded reachability properties for MDPs.
• RationalSearch method to solve equation systems exactly
• WalkerChae method for solving linear equation systems with guaranteed convergence
• Performance improvements for sparse model building
• Performance improvements for conditional properties on MDPs
• Automatically convert MA without probabilistic states into CTMC
• Fixed implemention of Fox and Glynn' algorithm
• storm-pars: support for welldefinedness constraints in mdps.
• storm-dft: split DFT settings into IO settings and fault tree settings
• storm-dft: removed obsolete explicit model builder for DFTs
• Features for developers:
  • Solvers can now expose requirements
  • unbounded reachability and reachability rewards now correctly respect solver requirements
  • Environment variables (such as the solver precisions) can now be handled more flexible
  • changes to Matrix-Vector operation interfaces, in particular fixed some issues with the use Intel TBB

Version 1.1.x

Version 1.1.0 (2017/8)

• Support for long-run average rewards on MDPs and Markov automata using a value-iteration based approach.
• Storm can now check MDPs and Markov Automata (i.e. MinMax equation systems) via Linear Programming.
• Parametric model checking is now handled in a separated library/executable called storm-pars.
• Wellformedness constraints on PMCs:
  • include constraints from rewards
  • are in smtlib2
  • fixed
  • computation of only constraints without doing model checking is now supported
• Fix for nested formulae
• JANI: Explicit engine supports custom model compositions.
• Support for parsing/building models given in the explicit input format of IMCA.
• Storm now overwrites files if asked to write files to a specific location.
• Changes in build process to accommodate for changes in carl. Also, more robust against issues with carl.
• USE_POPCNT removed in favor of FORCE_POPCNT. The popcnt instruction is used if available due to march=native, unless portable is set. Then, using FORCE_POPCNT enables the use of the SSE 4.2 instruction

Version 1.0.x

Version 1.0.1 (2017/4)

• Multi-objective model checking support now fully included
• Several improvements in parameter lifting
• Several improvements in JANI parsing
• Properties can contain model variables
• Support for rational numbers/functions in decision diagrams via sylvan
• Elimination-based solvers (exact solution) for models stored as decision diagrams
• Export of version and configuration to cmake
• Improved building process

Version 1.0.0 (2017/3)

Start of this changelog