pomdp 1.2.3 (05/04/2024)

Bugfixes

• Fixed possible memory violation in observation_matrix() and transition_matrix().

pomdp 1.2.1 (04/08/2024)

New Features

• read_POMDP gained parameter verbose to debug reading.
• solve_x check now that the model is of type x.
• Added some POMDP file examples.

Bugfixes

• Improved read_POMDP and write_POMDP.
• old LaTeX version on the CRAN master cannot deal with underscores in filenames. Rename the files cliff_walking_gridworld.png and
  windy_gridworld.png

pomdp 1.2.0 (04/02/2024)

New Features

• Added functions to work with MDP policies (see ? MDP_policy_functions).
• Added MDP solver functions: Q-learning, Sarsa, and expected Sarsa.
• simulate_MDP() and simulate_POMDP() gained parameter return_trajectories.
• New functions absorbing_states() and reachable_states() for MDPs and POMDPs.
• Support for gridworlds (see ? gridworld).
• New datasets: Cliff_walking, Windy_gridworld, RussianTiger
• plot_transition_graph() now hides unavailable actions.
• Added actions() to find available actions (unavailable actions have a reward of -Inf).
• Added make_partially_observable() and make_fully_observable() to convert between MDPs and POMDPs.

Changes

• simulate_POMDP(): Better calculation of T for infinite-horizon problems.
• several functions are now generics with methods for POMDP and MDP.
• policy() lost the parameters alpha and action.
• policy() and value_function() and gained the parameter drop.
• regret(): renamed parameter belief to start. Regret is now available for MDPs.
• simulate_MDP() stops now at absorbing states.
• simulate_MDP_cpp() works now with sparse model representation.
• POMDP and MDP gained field for additional info.
• approx_MDP_policy_evaluation() is now called MDP_policy_evaluation() and gained parameter theta as an additional stopping criterion.
• rewrote all accessor code reward_matrix, transition_matrix, observation_matrix for better and faster access.
• normalize() gained parameters for more detailed normalization.
• POMDP() and MDP() lost normalize.
• model.h has now support for keywords in transition_prob and observation_prob.
• MDP2POMDP is now make_partially_observable().

Bugfixes

• q_values_MDP(), solve_MDP(): Fixed reward representation issue.
• reward_val_cpp(): fixed observation matching bug.

pomdp 1.1.3 (12/20/2023)

New Features

• simulate_POMDP() and simulate_MDP() gained parameter delta_horizon and calculates now the horizon for infinite-horizon problems.
• added add_policy() and several consistency checks.

Changes

• Changed the action names for the Maze example to the names used in Russell and Norvig’s AIMA book.
• POMDP lost the parameter max. Costs need to be specified as negative rewards.

Bugfixes

• simulate_POMDP() now adds terminal values.

pomdp 1.1.2 (09/07/2023)

Bugfixes

• Fixed memory access bug in model.h

pomdp 1.1.1 (09/04/2023)

Changes

• plot_policy_graph(): The parameter order has slightly changed; belief_col is now called state_col; unreachable states are now suppressed.
• policy() gained parameters alpha and action.
• color palettes are now exported.
• POMPD accessors gain parameter drop.
• POMDP constructor and read_POMDP gained parameter normalize and, by default, normalize the POMDP definition.

New Features

• Large POMDP descriptions are now handled better by keeping the reward as a data.frame and supporting sparse matrices in the C++ code.
• New function value_function() to access alpha vectors.
• New function regret() to calculate the regret of a policy.
• transition_graph() to visualize the transition model.

pomdp 1.1.0 (01/23/2023)

New Features

• Added C++ (Rcpp) support. Speed up for simulate_POMDP, sample_belief_space, reward, …
• simulate_POMDP and sample_belief_space now have parallel (foreach) support.
• Sparse matrices from package Matrix for matrices with a density below 50%.
• Added support to parse matrices for POMDP files.
• Added model normalization.
• is_solved_POMDP(), is_converged_POMDP(), is_timedependent_POMDP(), and is_solved_MDP() are now exported.

Changes

• accessors are now called now transition_val() and observation_val().
• simulate_POMDP() and simulate_MDP() now return a list.
• reimplemented round_stochastic() to improve speed.
• MDP policy now uses factors for actions.
• estimate_belief_for_nodes() now can also use trajectories to estimate beliefs faster.
• cleaned up the interface for episodes and epochs.

pomdp 1.0.3 (05/18/2022)

• Fixed rounding issue on some architectures.

pomdp 1.0.2 (05/17/2022)

• policy_graph() can now produce policy trees for finite-horizon problems and the initial belief can be specified.
• simulate_POMDP(): fixed bug with not using horizon.
• reward() and reward_node_action() have now been separated.
• sample_belief_space() gained method ‘trajectories’.
• simulate_POMDP(): supports not epsilon-greedy policies.
• added x_prob() and x_val() functions to access individual parts of the matrices.
• fixed converged finite-horizon case. It now only returns the converged graph/alpha.
• we use not internally NA to represent * in the POMDP definition.
• actions, states and observations are now factors in most places.

pomdp 1.0.1 (03/25/2022)

• Fixed rounding issue on some architectures.
• Fixed bug in write_POMDP() (reported by emile-pelletier-gc).
• estimate_belief_for_nodes() is now exposed and the code has been improved.

pomdp 1.0.0 (02/23/2022)

• POMDP objects now have no list element model, but are the model list directly.
• moved pomdp-solve to package pomdpSolve.
• added solve_MDP().
• transition probability, observation probabilities and rewards can now be specified as a function.
• transition_matrix et al now can also return a function.
• Improved POMDP file writer.

pomdp 0.99.3 (08/05/2021)

• moved Ternary and visNetwork to SUGGESTED.
• removed clang warning for lex scanners.

pomdp 0.99.2 (05/14/2021)

Bugfix

• Removed nonportable flag -C from Makefile.

pomdp 0.99.1 (05/13/2021)

New Features

• Added a wrapper for the sarsop library.

Changes

• Improved error messages when accessing fields not parsed by read_POMDP.
• policy() no longer returns the graph, but just alphas and the optimal action.
• The maintainer is now mhahsler.

Bugfix

• Resolved issues with factors for R 4.0. We now mostly use character instead of factors.
• States and actions as numbers are now handled correctly (reported by meeheal).
• Added spelling fixes by brianrice2.
• Fixed buffer overflow for filename parameters in pomdpsolve.

pomdp 0.99.0 (05/04/2020)

Changes

• Support finite-horizon POMDPs and store epochs.
• reward now looks at different epochs, calculates the optimal actions and the parameter names are improved.
• solve_POMDP not looks at convergence.
• solve_POMDP gained parameter terminal_values.
• solve_POMDP gained parameter discount to overwrite the discount rate specified in the model.
• solve_POMDP can now solve POMDPs with time-dependent transition probabilities, observation probabilities and reward structure.
• solve_POMDP gained parameter grid in parameter list to specify a custom belief point grid for the grid method.
• write_POMDP and solve_POMDP gained parameter digits.
• added read_POMDP to read POMDP files.
• plot for POMDP is now replaced by plot_policy_graph.
• added policy graph visualization with visNetwork.
• added plot_value_function.
• added function sample_belief_space to sample from the belief space.
• added function plot_belief_space.
• added function transition_matrix.
• added function observation_matrix.
• added function reward_matrix.
• POMDP model now also contains horizon and terminal_values.
• added MDP formulated as a POMDP.
• added policy function to extract a better readable policy.
• added update_belief.
• added simulate_POMDP.
• added round_stochastic.
• added optimal_action.

pomdp 0.9.2 (12/06/2019)

Changes

• solve_POMDP can now solve POMDP files.
• added helper functions O, R and T.
• improved plot.
• Added reward function.
• values argument is now called max.
• Fixed class structure. The central class is not POMDP with elements model and solution.

Bugfix

• fixed warning for start = “uniform”.
• fixed warning in C code for gcc10.

pomdp 0.9.1-1 (05/14/2019)

Bugfix

• fixed warning in mdp.c for gcc9.

pomdp 0.9.1 (01/02/2019)

Bugfix

• Fixed Warning in fg-params.c

New Features

• New method transitions to extract the transition matrix from a POMDP.

pomdp 0.9.0 (12/25/2018)

Initial CRAN release.

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