CHANGELOG.md

Changelog

Changes starting with tag [USER] are of interest to end-users. Changes starting with tag [DEV] are of interest to developers only.

The tag [INPUT] indicates changes affecting the input files. The tag [OUTPUT] indicates changes affecting the output files.

Unreleased

1.3.0 - 2026-02-17

Added

• [INPUT] Parameter departure_time_interval can be used to define how accurately utility functions are computed for departure-time choice.

Changed

• [DEV] Update deprecated GitHub actions.

Fixed

• [INPUT] The warning message for forced releases now show the proper user id of the agent and edge (the internal index was used instead).
• [USER] Fix a crash when a vehicle headway is not a round value.
• [USER] Return error code 1 when the simulation failed (success code 0 was returned).

1.2.0 - 2026-01-15

Added

• [INPUT] Allow edges to have time-varying bottleneck flows with bottleneck_flows and bottleneck_times variables.
• [DEV] Add GNU General Public License v3.

Changed

• [INPUT] Arbitrary ids can be used for all input values (negative integers, strings).
• [DEV] Rename the repository from Metrolib to Metropolis-Core.
• [DEV] Update README.md.

Removed

• [USER] Remove the Tauri GUI (not useful and hard to maintain).

1.1.0 - 2025-06-06

Added

• [INPUT] The alpha parameter can be used to specify the value of time at the alternative or trip level (it has the same effect as the travel_utility.one or total_travel_utility.one variables, with an opposite sign).

Changed

• [INPUT] The AlphaBetaGamma schedule utility type is deprecated. Use Linear instead.

Fixed

• [INPUT] Road-network parameter max_pending_duration is now optional when spillback is disabled, as could be expected.
• [USER] Error messages where not shown if occurring before the loggers were initialized.
• [USER] Fix a bug when running routing_cli from the same directory where the parameters JSON file is located.
• [USER] Fix bugs when running a simulation without a road network.

Removed

• [USER] Remove the nested parquet example.

1.0.0 - 2025-01-06

First stable release of METROPOLIS2!

1.0.0-7 - 2024-12-21

Fixed

• [DEV] Revert to tauri 1.x to fix installer issues on Windows.

1.0.0-6 - 2024-12-17

Fixed

• [DEV] Fix duckscript bug in the release.
• [DEV] Fix bug with Tauri on MacOS.

1.0.0-5 - 2024-12-17

Added

• [INPUT] The "UpperBound" speed-function type can be used to limit the maximum speed at which a vehicle can travel.
• [USER] The error messages are logged to the log.txt output file.

Changed

• [USER] Improve the error message that is shown when some origin / destination nodes are not part of the road network.
• [INPUT] Default number of iterations (max_iterations) is 1 (it was 0).
• [OUTPUT] Update the terminology for running_times.json output file.
• [OUTPUT] Optimize file size of report.html.
• [DEV] Use jemalloc as allocator for improved performances on Linux systems.
• [DEV] Profile queries are not computed for origin-destination pairs with no departure-time choice.
• [DEV] Road-network skims are not computed when they are not needed (e.g., when all trips have a route given as input).
• [DEV] Do not compute search space for origin / destination nodes with few occurrences. A TCH query is run instead of Intersect query in this case.

Fixed

• [OUTPUT] Fix the computation for expected travel time difference RMSE.
• [DEV] Fix a stack overflow that could happen when recursively running too many events.
• [DEV] Various improvements and bug fixes.

1.0.0-4 - 2024-03-15

Changed

• [USER] The compute_choices executable is replaced by a only_compute_decisions parameter in the main executable.
• [USER] The compute_travel_times is renamed routing_cli and it is now able to road / write CSV and Parquet files.

Fixed

• [DEV] Various fixes to make the GUI compile through Github Actions.

1.0.0-rc.3 - 2024-03-15

Added

• [USER] Add back the GUI executable.

1.0.0-rc.2 - 2024-03-13

Removed

• [USER] Temporarily remove the GUI executable as it fails to compile on Windows and MacOS.

1.0.0-rc.1 - 2024-03-13

Added

• [USER] Prototype GUI for METROPOLIS2 with the binary metropolis_gui.
• [INPUT] The paths to the input files and the output directory are set in the parameters JSON file.
• [INPUT] Custom vehicle ids can be used (instead of vehicle indices numbered from 0 to n - 1).
• [INPUT] Add the max_iterations parameter in the simulation parameters to limit the number of iterations.

Changed

• [USER] The command-line interface only takes the path to the parameters JSON file as argument.
• [INPUT] The population and network input files accept the Parquet and CSV format instead of JSON.
• [INPUT] The road-network conditions input file accept the Parquet and CSV format instead of JSON.
• [INPUT] The road-network parameters are no longer nested in the network parameters.
• [OUTPUT] Use more interesting variables in the report HTML file.
• [OUTPUT] Use the new terminology in the report HTML file.
• [OUTPUT] The road-network conditions output files are saved in Parquet or CSV format instead of JSON (according to saving_format parameter).

Removed

• [INPUT] Stopping criteria can no longer be used in the parameters (use max_iterations parameter value instead).

0.8.0 - 2024-02-29

Added

• [INPUT] Add the ExponentialUnadjusted learning model (exponential model with no adjustment for the first iteration).
• [INPUT] Add option to force the route to be taken for road legs (parameter route of a road leg).
• [INPUT] Add option to set the speed at which the holes / free space left by vehicles leaving a road propagate backward (road-network parameter backward_wave_speed, default is infinite speed).
• [INPUT] Add option to remove the inflow constraint on edges (road-network parameter constrain_inflow, default is to constrain both inflows and outflows).
• [OUTPUT] Add the root mean squared difference of departure time in the iteration results.
• [OUTPUT] Add the root mean squared difference between simulated and expected travel time in the iteration results.
• [OUTPUT] Add the simulated and expected road-network weights RMSE (root mean squared difference) in the iteration results.
• [OUTPUT] Add the length of the route that is new compared to the previous iteration in the leg-level results.
• [OUTPUT] Add the departure time shift compared to the previous iteration in the trip-level and leg-level results.
• [OUTPUT] Add a boolean indicator indicating if an agent shifted mode compared to the previous iteration.
• [USER] Add a warning when deserializing a road network with parallel edges.

Changed

• [INPUT] For the Exponential learning model, the alpha value is no longer nested in a structure.
• [INPUT] Road edge's lane number can take non-integer values.
• [USER] For the Exponential learning model, the alpha value represents the weight of the simulated weights (previously, it was the expected weights).
• [USER] For speed-density functions, the travel time of a vehicle on an edge is based on the density before the vehicle enters the edge (i.e., not the density including the vehicle's own length as it was done previously).
• [USER] The departure-time stop criterion only considers the agents who did not switch to another mode (breaking change: the default value to use in case of mode switch is no longer required).
• [DEV] Run schemas generation with dev profile to reduce compile time.
• [DEV] Lints are configured directly in Cargo.toml, using Rust 1.74.0.
• [DEV] Road-network weights only store the weights of the edges which are accessible by the vehicle.

Fixed

• [OUTPUT] Fix a crash when running metropolis with an output directory that does not exist.
• [OUTPUT] Fix number of decimals for road-network weights RMSE in the report HTML file.
• [DEV] Fix nodes being duplicated when a graph is deserialized.
• [DEV] Fix crash when using a uniform random value equal to 1.0.

Removed

• [USER] The book and API documentation are not longer part of the released zipfile.

0.7.0 - 2023-11-16

Changed

• [OUTPUT] The iteration results are saved in a single file, iteration_results.ext, updated at each iteration. Previously they were saved in a different file for each iteration. The filetype and extension are based on the saving_format parameter (JSON, Parquet or CSV).
• [USER] Congestion is set to zero when free-flow travel time is zero, as a convention. Previously, congestion was set to NaN.
• [DEV] Use debug=false for dependencies to decrease the binary size.

Fixed

• [USER] A crash occurring for road legs with same origin as destination is fixed.

0.6.0 - 2023-10-24

Added

• [INPUT] The parameter saving_format can be used to choose the format of the output files (only for agent results for now). Possible values: JSON (default, previous format), Parquet, CSV.
• [INPUT] An id can be specify for the modes and the legs. These ids are then shown in the agent-results output.

Fixed

• [OUTPUT] Utility was not computed correctly for trips with only virtual legs.

0.5.2 - 2023-09-15

Changed

• [OUTPUT] The pre-computed route is no longer stored with the agent results for the compute_choices executable, instead, it is stored in a separate JSON file.

0.5.1 - 2023-09-14

Changed

• [OUTPUT] In the agent results, the pre-computed route is stored (field expected_route) whenever the field route is empty. For now, this only occurs when running the compute_choices executable.

Fixed

• [USER] The order in which ids are stored in the network-weights input is no longer relevant.

0.5.0 - 2023-07-28

Added

• [INPUT] Add mandatory parameter id to edges (must be unique and non-negative). This is a breaking change. The id is used in the output agent-results file (for the route) and in the network weights file (see below).
• [INPUT] Road-network parameter approximation_bound can be used to simplify the travel-time functions (and thus speed up the routing algorithm) at the cost of a small approximation.
• [OUTPUT] Add route length, route free-flow travel time and global free-flow travel time in the output of the compute_choices executable (whenever the route is pre-computed).
• [DEV] Add integration test loop to check for absence of loops in the routes.

Changed

• [INPUT] In the road-network input file, node ids no longer have to range from 0 to n - 1 (where n is the number of nodes).
• [INPUT] In the network-weights input and output file, the inner array of travel-time functions is replaced by an object that maps edge ids (parameter id of the edge) to the travel-time function. This is a breaking change.
• [USER] Remove loops in the route taken when they are detected, instead of just sending a warning.
• [USER] Compute the expected arrival time more accurately.
• [USER] When a vehicle is forced to be released on the next edge, it does not use any additional length so that the edge will not stay full for too long.

Fixed

• [USER] Consider the origin delay when pre-computing routes.

0.4.3 - 2023-07-06

Changed

• [DEV] Updated dependencies

0.4.2 - 2023-07-06

Added

• [INPUT] Can add constant values to each alternative in the DeterministicChoiceModel.
• [INPUT] Allow a discrete choice between different departure times for the departure-time choice model of Trip mode.
• [INPUT] Parameter pre_compute_route can be used to compute the routes of the trip in the pre-day model instead of the within-day model (better performances). By default, the parameter is true.

Changed

• [USER] Default is to allow overtaking on the edges.

0.4.1 - 2023-04-06

Added

• [INPUT] Add road-network parameter max_pending_duration to specify the delay after which vehicles are forced to enter the next edge in case of spillback.
• [INPUT] Add edge parameter overtaking to allow vehicles to overtake each other at the edge's exit bottleneck.
• [INPUT] Add road-network parameter algorithm_type to choose the algorithm used for origin-destination profile queries (TCH or Intersect). Default is to let the simulator guess the best algorithm.
• [INPUT] Network weights can be read directly from the output weight_results.json.zst (no need to decompress the file). Using a decompressed JSON file is still possible.
• [USER] Add the current time of the events in the within-day model progress bar.
• [USER] Ignore warnings when more than 20 have already been emitted.
• [USER] Add length of route difference in the output.
• [USER] Add compute_choices which can be used to compute choices from the pre-day model without running a full iteration.
• [DEV] Add a debug check that all agents have reached their destination.
• [DEV] Add more debug checks for the routes computed by the contraction hierarchies.
• [DEV] Use a memory allocation for events to speed-up their executions.

Changed

• [USER] The progress bars refresh only periodically, for improved speed and better ETA.

Fixed

• [USER] Fix the progress bar of the within-day model.
• [USER] Better formatting for the mean number of virtual legs in the HTML report.
• [USER] Improve TCH speed when some edges are restricted by discarding them from the graph.
• [USER] Fix how the weights are computed for restricted edges.
• [USER] Deserialize null or None values in the travel-time functions' points as Infinity.
• [DEV] Fix how waiting times and road length are recorded so that expected travel times are more accurate.
• [DEV] Fix how the spillback indicator is computed and reset.
• [DEV] Add a margin when checking FIFO property to avoid false positive.
• [DEV] In the TCH algorithms, never stall the source and target nodes (this prevented finding the best path when the source or the target was the candidate node).
• [DEV] In the TCH algorithms, use a margin when checking if a node can be stalled to prevent incorrect stalling because of rounding errors.

0.4.0 - 2023-03-12

Added

• [INPUT] Now road-network parameter spillback can be used to prevent vehicles from entering the edge if it is full (i.e., if the length of vehicles already on the edge is not smaller than the total length of the edge).
• [DEV] Add integration tests spillback and gridlock for the new spillback feature.

Changed

• [INPUT] The entry bottleneck and exit bottleneck of an edge must now have exactly the same flow. Road-edge parameter bottleneck_flow is used to set the bottleneck flow of an edge. (Former parameters bottleneck_inflow or bottleneck_outflow can be used as alias but only one of them must be set).
• [DEV] The signature of the execute function of events is simplified.
• [DEV] The VehicleEvent, RoadEdgeState, RoadNetworkState and NetworkState structs no longer hold references to simulation variables.
• [DEV] The EdgeEntryState and EdgeExitState structs replace the Bottleneck struct.
• [DEV] The RoadNodeState struct is now empty.

0.3.1 - 2023-03-07

Fixed

• [DEV] Fix Linux build.

0.3.0 - 2023-03-07

Added

• [INPUT] The number of threads to use for parallelized tasks can be specified in the parameters of the metropolis and compute_travel_times scripts (key is nb_threads).
• [USER] Add "Congestion and spillback modeling" section to the Book.

Changed

• [INPUT] Road-network parameter recording_interval specifies the distance between breakpoints for all piecewise-linear functions there are in Metropolis.
• [INPUT] The JSON representation of travel-time functions has changed (see the Book for details).

Removed

• [INPUT] All the *_simplification road-network parameters are removed (recording_interval parameter has superseded them).
• [DEV] The Simplification and NoSimplification PwlTTF variants are removed as they are no longer needed.

0.2.1 - 2023-02-18

Changed

• [DEV] Build Linux releases using MUSL for large compatibility.

0.2.0 - 2023-02-18

Added

• [INPUT] Add Trip mode which can represent trips by car (or any other mode) with intermediary stops. See the Book for more details.
• [USER] The simulation can be run with other initial weights than free flow, with the new --weights command line argument.
• [INPUT] The initial iteration counter to use for the simulation can be specified in the parameters of the simulation (variable init_iteration_counter).
• [INPUT] New type for the field utility_model for road modes: Polynomial, which takes as values degree 0, 1, 2, 3 and 4 coefficients of a polynomial function (constant, linear, quadratic and cubic functions are special cases of the Polynomial type).
• [OUTPUT] Add graph of arrival-times distribution for the last iteration in the HTML report.
• [OUTPUT] Add global free-flow travel time (OD free-flow travel time over any route) and global congestion to the output.
• [OUTPUT] Add road- and virtual- legs specific results in the report table.
• [USER] Add CHANGELOG.md to release zips.
• [USER] Add tags [USER] and [DEV] in the Changelog to specify the concerned individuals (end-users
• [USER] Add tags [INPUT] and [OUTPUT] in the Changelog to indicate that input or output files are affected.
• [USER] Add compute_travel_times executable (script to run many time-dependent routing queries).
• [USER] Add JSON Schemas for the compute_travel_times script in the directory schemas/tch/.
• [USER] Add book directory with a documentation for Metropolis (in progress).
• [DEV] Add a way not to simplify a PwlXYF when building it so that all breakpoints are kept.
• [DEV] Add functions constrain_to_domain, add_x_breakpoints, add_z_breakpoints, into_points, into_xs_and_ys and iter_eval to PwlXYF.
• [DEV] Add integration test legs for the new Leg mode.
• [DEV] Add functions route_free_flow_travel_time and route_length to RoadNetwork.

Changed

• [INPUT] [OUTPUT] The list of points for the piecewise-linear functions is serialized / deserialized as an array of arrays [x, y] (previously, it was an array of objects with keys x and y).
• [OUTPUT] The route taken by the agent (in the agent results) is serialized as an array of arrays [e, t], where e is the edge index and t is the entry time on the edge (previously it was an array of objects with keys edge and edge_entry).
• [USER] Complete the example so that it include all possible input formats.
• [INPUT] Rename attribute length of a vehicle to headway for clarity (length is set as an alias for backward compatibility).
• [USER] Validate that value t_star_high is not smaller than value t_star_low for the alpha-beta-gamma model.
• [USER] Add attribute readOnly to parameters min and max of PwlXYF in the JSON Schemas, so that the schema is consistent with the actual deserialization process.
• [USER] Various improvements to the compute_travel_times script (can output route, can guess best algorithm to use, etc.).
• [USER] JSON Schema files are organized in the directory schemas/metropolis/ and named differently.
• [USER] Metropolis executable is now stored in the execs directory.
• [DEV] Rename XYF function middle_departure_time to middle_x to be consistent with the terminology for the XYF functions.
• [DEV] Add a static lifetime requirement for TTFNum trait.
• [DEV] Enum ModeResults and struct TripResults are used to store mode-specific pre-day and within-day results. Previously, pre-day results were stored in PreDayChoices and RoadChoices, while within-day results were stored in ModeResults and RoadResults.
• [DEV] Trait Event now takes a timeline, allowing to use references to the simulation input in the events.

Removed

• [INPUT] The mode Road is removed (all the features are available with the new Trip mode).
• [INPUT] Parameters schedule_utility for an Agent is removed. The schedule utility is now specified at the mode-level.
• [Input] The parameter desired_arrival for AlphaBetaGammaModel is removed. The schedule utility is now explicitly specified for either the origin or destination (or intermediary stop) making this parameter useless.
• [DEV] The PreDayResult struct is removed (everything is stored directly in AgentResult and ModeResults now).

Deprecated

• [INPUT] The types None, Proportional and Quadratic for field utility_model raise a deprecated warning when used.

Fixed

• [USER] Deserialize null values for constant travel-time functions as Infinity, consistently with how the such values are serialized.
• [DEV] Make functions iter_eval and add_x_breakpoints for PwlXYF works properly for points after the last point of the PwlXYF.
• [DEV] Run Clippy with cargo-make.
• [DEV] Run the examples with cargo-make.

0.1.7 - 2023-01-05

Modify

• [DEV] When generating JSON schemas, output directory is automatically created if it does not exist.

0.1.6 - 2023-01-05

Added

• [USER] Allowed / restricted edges can be specified for each vehicle type through fields allowed_edges and restricted_edges.

Changed

• [DEV] In the pre-processing of the road network, a set of unique vehicle types is computed (two vehicle types are considered identical if they can share the same network weights and skims, i.e., they have the same speed function, allowed edges and restricted edges).
• [USER] Road network weights and skims are stored and computed for each unique vehicle type (previously, this was done for each vehicle type).
• [DEV] Some tweaks were done for cargo-make (e.g., no verbose output, Clippy by default).

Fixed

• [DEV] Various fixes for GitHub Actions.
• [USER] Fix EdgeIndex not properly document in the JSON Schemas.

0.1.5 - 2022-12-21

Added

• [DEV] The Changelog is automatically added to the GitHub releases.

Changed

• [DEV] Do not compile all features by default with cargo-make.

Fixed

• [DEV] Fix compiling with cargo-make on Windows and MacOS.
• [USER] Fix links to releases in the Changelog.

0.1.4 - 2022-12-20

Added

• [DEV] Add Makefile.toml to control the behavior of cargo-make.
• [USER] Add this changelog.
• [USER] Add README file.

0.1.3 - 2022-12-20

Fixed

• [DEV] Install cargo-make during the publish workflow.

0.1.2 - 2022-12-20

Fixed

• [DEV] Fix the filter used to detect tags of new releases.

0.1.1 - 2022-12-20

Added

• [DEV] Use cargo-make and GitHub Actions to automate building, testing and releasing new versions.

Changed

• [USER] New format for logs.
• [USER] Default log level is INFO for logs to stdout and DEBUG for logs to file.
• [DEV] Do not output source code in the documentation.

Fixed

• [DEV] Feature Jemalloc is disabled for Windows.
• [DEV] Fix License filename.

Security

• [DEV] Remove chrono dependency that depends on a vulnerable version of time.

0.1.0 - 2022-12-12

Added

• First release of Metrolib, there are two many things to list.