v24.11.2

Bug fixes

• Reverted modifications to quickplot from #4529 which caused issues with the plots displaying correct variable names. (#4622)

v24.11.1

Features

• Modified quick_plot.plot to accept a list of times and generate superimposed graphs for specified time points. (#4529)

Bug Fixes

• Added some dependencies which were left out of the pyproject.toml file (#4602)

v24.11.0

Features

• Added CoupledVariable which provides a placeholder variable whose equation can be elsewhere in the model. (#4556)
• Adds support to pybamm.Experiment for the output_variables option in the IDAKLUSolver. (#4534)
• Adds an option "voltage as a state" that can be "false" (default) or "true". If "true" adds an explicit algebraic equation for the voltage. (#4507)
• Improved QuickPlot accuracy for simulations with Hermite interpolation. (#4483)
• Added Hermite interpolation to the (IDAKLUSolver) that improves the accuracy and performance of post-processing variables. (#4464)
• Added basic telemetry to record which functions are being run. See Telemetry section in the User Guide for more information. (#4441)
• Added BasicDFN model for sodium-ion batteries (#4451)
• Added sensitivity calculation support for pybamm.Simulation and pybamm.Experiment (#4415)
• Added OpenMP parallelization to IDAKLU solver for lists of input parameters (#4449)
• Added phase-dependent particle options to LAM (#4369)
• Added a lithium ion equivalent circuit model with split open circuit voltages for each electrode (SplitOCVR). (#4330)
• Added the pybamm.DiscreteTimeSum expression node to sum an expression over a sequence of data times, and accompanying pybamm.DiscreteTimeData class to store the data times and values (#4501)

Optimizations

• Performance refactor of JAX BDF Solver with default Jax method set to "BDF". (#4456)
• Improved performance of initialization and reinitialization of ODEs in the (IDAKLUSolver). (#4453)
• Removed the start_step_offset setting and disabled minimum dt warnings for drive cycles with the (IDAKLUSolver). (#4416)

Bug Fixes

• Added error for binary operators on two concatenations with different numbers of children. Previously, the extra children were dropped. Also fixed bug where Q_rxn was dropped from the total heating term in half-cell models. (#4562)
• Fixed bug where Q_rxn was set to 0 for the negative electrode in half-cell models. (#4557)
• Fixed bug in post-processing solutions with infeasible experiments using the (IDAKLUSolver). (#4541)
• Disabled IREE on MacOS due to compatibility issues and added the CasADI
  path to the environment to resolve issues on MacOS and Linux. Windows
  users may still experience issues with interpolation. (#4528)
• Added _from_json() functionality to Sign which was erroneously omitted previously. (#4517)
• Fixed bug where IDAKLU solver failed when output variables were specified and an extrapolation event is present. (#4440)

Breaking changes

• Deprecated pybamm.Simulation.set_parameters and pybamm.Simulation.set_up_and_parameterise_experiment functions in pybamm/simulation.py. (#3752)
• Removed all instances of param = self.param and now directly access self.param across the codebase. This change simplifies parameter references and enhances readability. (#4484)
• Removed the deprecation warning for the chemistry argument in
  pybamm.ParameterValues (#4466)
• The parameters "... electrode OCP entropic change [V.K-1]" and "... electrode volume change" are now expected to be functions of stoichiometry only instead of functions of both stoichiometry and maximum concentration (#4427)
• Renamed set_events function to add_events_from to better reflect its purpose. (#4421)

v24.9.0

Features

• Added additional user-configurable options to the (IDAKLUSolver) and adjusted the default values to improve performance. (#4282)
• Added the diffusion element to be used in the Thevenin model. (#4254)

Optimizations

• Update IDAKLU tests and benchmarks to use adaptive time stepping. (#4390)
• Improved adaptive time-stepping performance of the (IDAKLUSolver). (#4351)
• Improved performance and reliability of DAE consistent initialization. (#4301)
• Replaced rounded Faraday constant with its exact value in bpx.py for better comparison between different tools. (#4290)

Bug Fixes

• Fixed memory issue that caused failure when output variables were specified with (IDAKLUSolver). (#4379)
• Fixed bug where IDAKLU solver failed when output variables were specified and an event triggered. (#4300)

Breaking changes

• Replaced have_jax with has_jax, have_idaklu with has_idaklu, and
  have_iree with has_iree (#4398)
• Remove deprecated function pybamm_install_jax (#4362)
• Removed legacy python-IDAKLU solver. (#4326)

v24.5

Features

• Added new parameters "f{pref]Initial inner SEI on cracks thickness [m]" and "f{pref]Initial outer SEI on cracks thickness [m]", instead of hardcoding these to L_inner_0 / 10000 and L_outer_0 / 10000. (#4168)
• Added pybamm.DataLoader class to fetch data files from pybamm-data and store it under local cache. (#4098)
• Added time as an option for Experiment.termination. Now allows solving up to a user-specified time while also allowing different cycles and steps in an experiment to be handled normally. (#4073)
• Added plot_thermal_components to plot the contributions to the total heat generation in a battery (#4021)
• Added functions for normal probability density function (pybamm.normal_pdf) and cumulative distribution function (pybamm.normal_cdf) (#3999)
• "Basic" models are now compatible with experiments (#3995)
• Updates multiprocess Pool in BaseSolver.solve() to be constructed with context fork. Adds small example for multiprocess inputs. (#3974)
• Lithium plating now works on composite electrodes (#3919)
• Added lithium plating parameters to Ecker2015 and Ecker2015_graphite_halfcell parameter sets (#3919)
• Added custom experiment steps (#3835)
• MSMR open-circuit voltage model now depends on the temperature (#3832)
• Added support for macOS arm64 (M-series) platforms. (#3789)
• Added the ability to specify a custom solver tolerance in get_initial_stoichiometries and related functions (#3714)
• Modified step function to take an array of time t_eval as an argument and deprecated use of npts. (#3627)
• Renamed "electrode diffusivity" to "particle diffusivity" as a non-breaking change with a deprecation warning (#3624)
• Add support for BPX version 0.4.0 which allows for blended electrodes and user-defined parameters in BPX(#3414)
• Added by_submodel feature in print_parameter_info method to allow users to print parameters and types of submodels in a tabular and readable format (#3628)
• Added WyciskOpenCircuitPotential for differential capacity hysteresis state open-circuit potential submodel (#3593)
• Transport efficiency submodel has new options from the literature relating to different tortuosity factor models and also a new option called "tortuosity factor" for specifying the value or function directly as parameters (#3437)
• Heat of mixing source term can now be included into thermal models (#2837)
• Added a JAX interface to the IDAKLU solver (#3658)

Bug Fixes

• Fixed bug where passing deprecated electrode diffusivity parameter resulted in a breaking change and/or the corresponding diffusivity parameter not updating. Improved the deprecated translation around BPX. (#4176)
• Fixed a bug where a factor of electrode surface area to volume ratio is missing in the rhs of the LeadingOrderDifferential conductivity model (#4139)
• Fixes the breaking changes caused by #3624, specifically enables the deprecated parameter electrode diffusivity to be used by ParameterValues.update({name:value}) and Solver.solve(inputs={name:value}). Fixes parameter translation from old name to new name, with corrected tests. (#4072
• Set the remove_independent_variables_from_rhs to False by default, and moved the option from Discretisation.process_model to Discretisation.__init__. This fixes a bug related to the discharge capacity, but may make the simulation slower in some cases. To set the option to True, use Simulation(..., discretisation_kwargs={"remove_independent_variables_from_rhs": True}). (#4020)
• Fixed a bug where independent variables were removed from models even if they appeared in events (#4019)
• Fix bug with upwind and downwind schemes producing the wrong discretised system (#3979)
• Allow evaluation of an Interpolant object with a number (#3932)
• Added scale to dead lithium variable (#3919)
• plot_voltage_components now works even if the time does not start at 0 (#3915)
• Fixed bug where separator porosity was used in calculation instead of transport efficiency (#3905)
• Initial voltage can now match upper or lower cut-offs exactly (#3842)
• Fixed a bug where 1+1D and 2+1D models would not work with voltage or power controlled experiments(#3829)
• Update IDAKLU solver to fail gracefully when a variable is requested that was not in the solves output_variables list (#3803)
• Updated _steps_util.py to throw a specific exception when drive cycle starts at t>0 (#3756)
• Updated plot_voltage_components.py to support both Simulation and Solution objects. Added new methods in both Simulation and Solution classes for allow the syntax simulation.plot_voltage_components and solution.plot_voltage_components. Updated test_plot_voltage_components.py to reflect these changes (#3723).
• The SEI thickness decreased at some intervals when the 'electron-migration limited' model was used. It has been corrected (#3622)
• Allow input parameters in ESOH model (#3921)
• Use casadi MX.interpn_linear function instead of plugin to fix casadi_interpolant_linear.dll not found on Windows (#4077)

Optimizations

• Sped up initialization of a ProcessedVariable by making the internal xarray.DataArray initialization lazy (only gets created if interpolation is needed) (#3862)

Breaking changes

• Functions that are created using pybamm.Function(function_object, children) can no longer be differentiated symbolically (e.g. to compute the Jacobian). This should affect no users, since function derivatives for all "standard" functions are explicitly implemented (#4196)
• Removed data files under pybamm/input and released them in a separate repository upstream at pybamm-data. Note that data files under pybamm/input/parameters have not been removed. (#4098)
• Removed check_model argument from Simulation.solve. To change the check_model option, use Simulation(..., discretisation_kwargs={"check_model": False}). (#4020)
• Removed multiple Docker images. Here on, a single Docker image tagged pybamm/pybamm:latest will be provided with both solvers (IDAKLU and JAX) pre-installed. (#3992)
• Removed support for Python 3.8 (#3961)
• Renamed "ocp_soc_0_dimensional" to "ocp_soc_0" and "ocp_soc_100_dimensional" to "ocp_soc_100" (#3942)
• The ODES solver was removed due to compatibility issues. Users should use IDAKLU, Casadi, or JAX instead. (#3932)
• Integrated the [pandas] extra into the core PyBaMM package, deprecating the pybamm[pandas] optional dependency. Pandas is now a required dependency and will be installed upon installing PyBaMM (#3892)
• Renamed "have_optional_dependency" to "import_optional_dependency" (#3866)
• Integrated the [latexify] extra into the core PyBaMM package, deprecating the pybamm[latexify] set of optional dependencies. SymPy is now a required dependency and will be installed upon installing PyBaMM (#3848)
• Renamed "testing" argument for plots to "show_plot" and flipped its meaning (show_plot=True is now the default and shows the plot) (#3842)
• Dropped support for BPX version 0.3.0 and below (#3414)
• The function get_spatial_var in `pybamm.Qui...

v24.5rc2

Features

• Added new parameters "f{pref]Initial inner SEI on cracks thickness [m]" and "f{pref]Initial outer SEI on cracks thickness [m]", instead of hardcoding these to L_inner_0 / 10000 and L_outer_0 / 10000. (#4168)
• Added pybamm.DataLoader class to fetch data files from pybamm-data and store it under local cache. (#4098)
• Added time as an option for Experiment.termination. Now allows solving up to a user-specified time while also allowing different cycles and steps in an experiment to be handled normally. (#4073)
• Added plot_thermal_components to plot the contributions to the total heat generation in a battery (#4021)
• Added functions for normal probability density function (pybamm.normal_pdf) and cumulative distribution function (pybamm.normal_cdf) (#3999)
• "Basic" models are now compatible with experiments (#3995)
• Updates multiprocess Pool in BaseSolver.solve() to be constructed with context fork. Adds small example for multiprocess inputs. (#3974)
• Lithium plating now works on composite electrodes (#3919)
• Added lithium plating parameters to Ecker2015 and Ecker2015_graphite_halfcell parameter sets (#3919)
• Added custom experiment steps (#3835)
• MSMR open-circuit voltage model now depends on the temperature (#3832)
• Added support for macOS arm64 (M-series) platforms. (#3789)
• Added the ability to specify a custom solver tolerance in get_initial_stoichiometries and related functions (#3714)
• Modified step function to take an array of time t_eval as an argument and deprecated use of npts. (#3627)
• Renamed "electrode diffusivity" to "particle diffusivity" as a non-breaking change with a deprecation warning (#3624)
• Add support for BPX version 0.4.0 which allows for blended electrodes and user-defined parameters in BPX(#3414)
• Added by_submodel feature in print_parameter_info method to allow users to print parameters and types of submodels in a tabular and readable format (#3628)
• Added WyciskOpenCircuitPotential for differential capacity hysteresis state open-circuit potential submodel (#3593)
• Transport efficiency submodel has new options from the literature relating to different tortuosity factor models and also a new option called "tortuosity factor" for specifying the value or function directly as parameters (#3437)
• Heat of mixing source term can now be included into thermal models (#2837)

Bug Fixes

• Fixed bug where passing deprecated electrode diffusivity parameter resulted in a breaking change and/or the corresponding diffusivity parameter not updating. Improved the deprecated translation around BPX. (#4176)
• Fixed a bug where a factor of electrode surface area to volume ratio is missing in the rhs of the LeadingOrderDifferential conductivity model (#4139)
• Fixes the breaking changes caused by #3624, specifically enables the deprecated parameter electrode diffusivity to be used by ParameterValues.update({name:value}) and Solver.solve(inputs={name:value}). Fixes parameter translation from old name to new name, with corrected tests. (#4072
• Set the remove_independent_variables_from_rhs to False by default, and moved the option from Discretisation.process_model to Discretisation.__init__. This fixes a bug related to the discharge capacity, but may make the simulation slower in some cases. To set the option to True, use Simulation(..., discretisation_kwargs={"remove_independent_variables_from_rhs": True}). (#4020)
• Fixed a bug where independent variables were removed from models even if they appeared in events (#4019)
• Fix bug with upwind and downwind schemes producing the wrong discretised system (#3979)
• Allow evaluation of an Interpolant object with a number (#3932)
• Added scale to dead lithium variable (#3919)
• plot_voltage_components now works even if the time does not start at 0 (#3915)
• Fixed bug where separator porosity was used in calculation instead of transport efficiency (#3905)
• Initial voltage can now match upper or lower cut-offs exactly (#3842)
• Fixed a bug where 1+1D and 2+1D models would not work with voltage or power controlled experiments(#3829)
• Update IDAKLU solver to fail gracefully when a variable is requested that was not in the solves output_variables list (#3803)
• Updated _steps_util.py to throw a specific exception when drive cycle starts at t>0 (#3756)
• Updated plot_voltage_components.py to support both Simulation and Solution objects. Added new methods in both Simulation and Solution classes for allow the syntax simulation.plot_voltage_components and solution.plot_voltage_components. Updated test_plot_voltage_components.py to reflect these changes (#3723).
• The SEI thickness decreased at some intervals when the 'electron-migration limited' model was used. It has been corrected (#3622)
• Allow input parameters in ESOH model (#3921)
• Use casadi MX.interpn_linear function instead of plugin to fix casadi_interpolant_linear.dll not found on Windows (#4077)

Optimizations

• Sped up initialization of a ProcessedVariable by making the internal xarray.DataArray initialization lazy (only gets created if interpolation is needed) (#3862)

Breaking changes

• Functions that are created using pybamm.Function(function_object, children) can no longer be differentiated symbolically (e.g. to compute the Jacobian). This should affect no users, since function derivatives for all "standard" functions are explicitly implemented (#4196)
• Removed data files under pybamm/input and released them in a separate repository upstream at pybamm-data. Note that data files under pybamm/input/parameters have not been removed. (#4098)
• Removed check_model argument from Simulation.solve. To change the check_model option, use Simulation(..., discretisation_kwargs={"check_model": False}). (#4020)
• Removed multiple Docker images. Here on, a single Docker image tagged pybamm/pybamm:latest will be provided with both solvers (IDAKLU and JAX) pre-installed. (#3992)
• Removed support for Python 3.8 (#3961)
• Renamed "ocp_soc_0_dimensional" to "ocp_soc_0" and "ocp_soc_100_dimensional" to "ocp_soc_100" (#3942)
• The ODES solver was removed due to compatibility issues. Users should use IDAKLU, Casadi, or JAX instead. (#3932)
• Integrated the [pandas] extra into the core PyBaMM package, deprecating the pybamm[pandas] optional dependency. Pandas is now a required dependency and will be installed upon installing PyBaMM (#3892)
• Renamed "have_optional_dependency" to "import_optional_dependency" (#3866)
• Integrated the [latexify] extra into the core PyBaMM package, deprecating the pybamm[latexify] set of optional dependencies. SymPy is now a required dependency and will be installed upon installing PyBaMM (#3848)
• Renamed "testing" argument for plots to "show_plot" and flipped its meaning (show_plot=True is now the default and shows the plot) (#3842)
• Dropped support for BPX version 0.3.0 and below (#3414)

v24.5rc1

Features

• Added functionality to pass in arbitrary functions of time as the argument for a (pybamm.step). (#4222)
• Added new parameters "f{pref]Initial inner SEI on cracks thickness [m]" and "f{pref]Initial outer SEI on cracks thickness [m]", instead of hardcoding these to L_inner_0 / 10000 and L_outer_0 / 10000. (#4168)
• Added pybamm.DataLoader class to fetch data files from pybamm-data and store it under local cache. (#4098)
• Added time as an option for Experiment.termination. Now allows solving up to a user-specified time while also allowing different cycles and steps in an experiment to be handled normally. (#4073)
• Added plot_thermal_components to plot the contributions to the total heat generation in a battery (#4021)
• Added functions for normal probability density function (pybamm.normal_pdf) and cumulative distribution function (pybamm.normal_cdf) (#3999)
• "Basic" models are now compatible with experiments (#3995)
• Updates multiprocess Pool in BaseSolver.solve() to be constructed with context fork. Adds small example for multiprocess inputs. (#3974)
• Lithium plating now works on composite electrodes (#3919)
• Added lithium plating parameters to Ecker2015 and Ecker2015_graphite_halfcell parameter sets (#3919)
• Added custom experiment steps (#3835)
• MSMR open-circuit voltage model now depends on the temperature (#3832)
• Added support for macOS arm64 (M-series) platforms. (#3789)
• Added the ability to specify a custom solver tolerance in get_initial_stoichiometries and related functions (#3714)
• Modified step function to take an array of time t_eval as an argument and deprecated use of npts. (#3627)
• Renamed "electrode diffusivity" to "particle diffusivity" as a non-breaking change with a deprecation warning (#3624)
• Add support for BPX version 0.4.0 which allows for blended electrodes and user-defined parameters in BPX(#3414)
• Added by_submodel feature in print_parameter_info method to allow users to print parameters and types of submodels in a tabular and readable format (#3628)
• Added WyciskOpenCircuitPotential for differential capacity hysteresis state open-circuit potential submodel (#3593)
• Transport efficiency submodel has new options from the literature relating to different tortuosity factor models and also a new option called "tortuosity factor" for specifying the value or function directly as parameters (#3437)
• Heat of mixing source term can now be included into thermal models (#2837)

Bug Fixes

• Fixed bug where passing deprecated electrode diffusivity parameter resulted in a breaking change and/or the corresponding diffusivity parameter not updating. Improved the deprecated translation around BPX. (#4176)
• Fixed a bug where a factor of electrode surface area to volume ratio is missing in the rhs of the LeadingOrderDifferential conductivity model (#4139)
• Fixes the breaking changes caused by #3624, specifically enables the deprecated parameter electrode diffusivity to be used by ParameterValues.update({name:value}) and Solver.solve(inputs={name:value}). Fixes parameter translation from old name to new name, with corrected tests. (#4072
• Set the remove_independent_variables_from_rhs to False by default, and moved the option from Discretisation.process_model to Discretisation.__init__. This fixes a bug related to the discharge capacity, but may make the simulation slower in some cases. To set the option to True, use Simulation(..., discretisation_kwargs={"remove_independent_variables_from_rhs": True}). (#4020)
• Fixed a bug where independent variables were removed from models even if they appeared in events (#4019)
• Fix bug with upwind and downwind schemes producing the wrong discretised system (#3979)
• Allow evaluation of an Interpolant object with a number (#3932)
• Added scale to dead lithium variable (#3919)
• plot_voltage_components now works even if the time does not start at 0 (#3915)
• Fixed bug where separator porosity was used in calculation instead of transport efficiency (#3905)
• Initial voltage can now match upper or lower cut-offs exactly (#3842)
• Fixed a bug where 1+1D and 2+1D models would not work with voltage or power controlled experiments(#3829)
• Update IDAKLU solver to fail gracefully when a variable is requested that was not in the solves output_variables list (#3803)
• Updated _steps_util.py to throw a specific exception when drive cycle starts at t>0 (#3756)
• Updated plot_voltage_components.py to support both Simulation and Solution objects. Added new methods in both Simulation and Solution classes for allow the syntax simulation.plot_voltage_components and solution.plot_voltage_components. Updated test_plot_voltage_components.py to reflect these changes (#3723).
• The SEI thickness decreased at some intervals when the 'electron-migration limited' model was used. It has been corrected (#3622)
• Allow input parameters in ESOH model (#3921)
• Use casadi MX.interpn_linear function instead of plugin to fix casadi_interpolant_linear.dll not found on Windows (#4077)

Optimizations

• Sped up initialization of a ProcessedVariable by making the internal xarray.DataArray initialization lazy (only gets created if interpolation is needed) (#3862)

Breaking changes

• Functions that are created using pybamm.Function(function_object, children) can no longer be differentiated symbolically (e.g. to compute the Jacobian). This should affect no users, since function derivatives for all "standard" functions are explicitly implemented (#4196)
• Removed data files under pybamm/input and released them in a separate repository upstream at pybamm-data. Note that data files under pybamm/input/parameters have not been removed. (#4098)
• Removed check_model argument from Simulation.solve. To change the check_model option, use Simulation(..., discretisation_kwargs={"check_model": False}). (#4020)
• Removed multiple Docker images. Here on, a single Docker image tagged pybamm/pybamm:latest will be provided with both solvers (IDAKLU and JAX) pre-installed. (#3992)
• Removed support for Python 3.8 (#3961)
• Renamed "ocp_soc_0_dimensional" to "ocp_soc_0" and "ocp_soc_100_dimensional" to "ocp_soc_100" (#3942)
• The ODES solver was removed due to compatibility issues. Users should use IDAKLU, Casadi, or JAX instead. (#3932)
• Integrated the [pandas] extra into the core PyBaMM package, deprecating the pybamm[pandas] optional dependency. Pandas is now a required dependency and will be installed upon installing PyBaMM (#3892)
• Renamed "have_optional_dependency" to "import_optional_dependency" (#3866)
• Integrated the [latexify] extra into the core PyBaMM package, deprecating the pybamm[latexify] set of optional dependencies. SymPy is now a required dependency and will be installed upon installing PyBaMM (#3848)
• Renamed "testing" argument for plots to "show_plot" and flipped its meaning (show_plot=True is now the default and shows the plot) (#3842)
• Dropped support for BPX version 0.3.0 and below ([#3414](https://github.com/pybamm-team/PyBaMM/pull/...

v24.5rc0

Features

• Added new parameters "f{pref]Initial inner SEI on cracks thickness [m]" and "f{pref]Initial outer SEI on cracks thickness [m]", instead of hardcoding these to L_inner_0 / 10000 and L_outer_0 / 10000. (#4168)
• Added pybamm.DataLoader class to fetch data files from pybamm-data and store it under local cache. (#4098)
• Added time as an option for Experiment.termination. Now allows solving up to a user-specified time while also allowing different cycles and steps in an experiment to be handled normally. (#4073)
• Added plot_thermal_components to plot the contributions to the total heat generation in a battery (#4021)
• Added functions for normal probability density function (pybamm.normal_pdf) and cumulative distribution function (pybamm.normal_cdf) (#3999)
• "Basic" models are now compatible with experiments (#3995)
• Updates multiprocess Pool in BaseSolver.solve() to be constructed with context fork. Adds small example for multiprocess inputs. (#3974)
• Lithium plating now works on composite electrodes (#3919)
• Added lithium plating parameters to Ecker2015 and Ecker2015_graphite_halfcell parameter sets (#3919)
• Added custom experiment steps (#3835)
• MSMR open-circuit voltage model now depends on the temperature (#3832)
• Added support for macOS arm64 (M-series) platforms. (#3789)
• Added the ability to specify a custom solver tolerance in get_initial_stoichiometries and related functions (#3714)
• Modified step function to take an array of time t_eval as an argument and deprecated use of npts. (#3627)
• Renamed "electrode diffusivity" to "particle diffusivity" as a non-breaking change with a deprecation warning (#3624)
• Add support for BPX version 0.4.0 which allows for blended electrodes and user-defined parameters in BPX(#3414)
• Added by_submodel feature in print_parameter_info method to allow users to print parameters and types of submodels in a tabular and readable format (#3628)
• Added WyciskOpenCircuitPotential for differential capacity hysteresis state open-circuit potential submodel (#3593)
• Transport efficiency submodel has new options from the literature relating to different tortuosity factor models and also a new option called "tortuosity factor" for specifying the value or function directly as parameters (#3437)
• Heat of mixing source term can now be included into thermal models (#2837)

Bug Fixes

• Fixed bug where passing deprecated electrode diffusivity parameter resulted in a breaking change and/or the corresponding diffusivity parameter not updating. Improved the deprecated translation around BPX. (#4176)
• Fixed a bug where a factor of electrode surface area to volume ratio is missing in the rhs of the LeadingOrderDifferential conductivity model (#4139)
• Fixes the breaking changes caused by #3624, specifically enables the deprecated parameter electrode diffusivity to be used by ParameterValues.update({name:value}) and Solver.solve(inputs={name:value}). Fixes parameter translation from old name to new name, with corrected tests. (#4072
• Set the remove_independent_variables_from_rhs to False by default, and moved the option from Discretisation.process_model to Discretisation.__init__. This fixes a bug related to the discharge capacity, but may make the simulation slower in some cases. To set the option to True, use Simulation(..., discretisation_kwargs={"remove_independent_variables_from_rhs": True}). (#4020)
• Fixed a bug where independent variables were removed from models even if they appeared in events (#4019)
• Fix bug with upwind and downwind schemes producing the wrong discretised system (#3979)
• Allow evaluation of an Interpolant object with a number (#3932)
• Added scale to dead lithium variable (#3919)
• plot_voltage_components now works even if the time does not start at 0 (#3915)
• Fixed bug where separator porosity was used in calculation instead of transport efficiency (#3905)
• Initial voltage can now match upper or lower cut-offs exactly (#3842)
• Fixed a bug where 1+1D and 2+1D models would not work with voltage or power controlled experiments(#3829)
• Update IDAKLU solver to fail gracefully when a variable is requested that was not in the solves output_variables list (#3803)
• Updated _steps_util.py to throw a specific exception when drive cycle starts at t>0 (#3756)
• Updated plot_voltage_components.py to support both Simulation and Solution objects. Added new methods in both Simulation and Solution classes for allow the syntax simulation.plot_voltage_components and solution.plot_voltage_components. Updated test_plot_voltage_components.py to reflect these changes (#3723).
• The SEI thickness decreased at some intervals when the 'electron-migration limited' model was used. It has been corrected (#3622)
• Allow input parameters in ESOH model (#3921)
• Use casadi MX.interpn_linear function instead of plugin to fix casadi_interpolant_linear.dll not found on Windows (#4077)

Optimizations

• Sped up initialization of a ProcessedVariable by making the internal xarray.DataArray initialization lazy (only gets created if interpolation is needed) (#3862)

Breaking changes

• Functions that are created using pybamm.Function(function_object, children) can no longer be differentiated symbolically (e.g. to compute the Jacobian). This should affect no users, since function derivatives for all "standard" functions are explicitly implemented (#4196)
• Removed data files under pybamm/input and released them in a separate repository upstream at pybamm-data. Note that data files under pybamm/input/parameters have not been removed. (#4098)
• Removed check_model argument from Simulation.solve. To change the check_model option, use Simulation(..., discretisation_kwargs={"check_model": False}). (#4020)
• Removed multiple Docker images. Here on, a single Docker image tagged pybamm/pybamm:latest will be provided with both solvers (IDAKLU and JAX) pre-installed. (#3992)
• Removed support for Python 3.8 (#3961)
• Renamed "ocp_soc_0_dimensional" to "ocp_soc_0" and "ocp_soc_100_dimensional" to "ocp_soc_100" (#3942)
• The ODES solver was removed due to compatibility issues. Users should use IDAKLU, Casadi, or JAX instead. (#3932)
• Integrated the [pandas] extra into the core PyBaMM package, deprecating the pybamm[pandas] optional dependency. Pandas is now a required dependency and will be installed upon installing PyBaMM (#3892)
• Renamed "have_optional_dependency" to "import_optional_dependency" (#3866)
• Integrated the [latexify] extra into the core PyBaMM package, deprecating the pybamm[latexify] set of optional dependencies. SymPy is now a required dependency and will be installed upon installing PyBaMM (#3848)
• Renamed "testing" argument for plots to "show_plot" and flipped its meaning (show_plot=True is now the default and shows the plot) (#3842)
• Dropped support for BPX version 0.3.0 and below (#3414)

v24.1

Features

• The pybamm_install_odes command now includes support for macOS systems and can be used to set up SUNDIALS and install the scikits.odes solver on macOS (#3417, #3706)
• Added support for Python 3.12 (#3531)
• Added method to get QuickPlot axes by variable (#3596)
• Added custom experiment terminations (#3596)
• Mechanical parameters are now a function of stoichiometry and temperature (#3576)
• Added a new unary operator, EvaluateAt, that evaluates a spatial variable at a given position (#3573)
• Added a method, insert_reference_electrode, to pybamm.lithium_ion.BaseModel that insert a reference electrode to measure the electrolyte potential at a given position in space and adds new variables that mimic a 3E cell setup. (#3573)
• Serialisation added so models can be written to/read from JSON (#3397)
• Added a get_parameter_info method for models and modified "print_parameter_info" functionality to extract all parameters and their type in a tabular and readable format (#3584)
• Mechanical parameters are now a function of stoichiometry and temperature (#3576)

Bug fixes

• Fixed a bug that lead to a ShapeError when specifying "Ambient temperature [K]" as an Interpolant with an isothermal model (#3761)
• Fixed a bug where if the first step(s) in a cycle are skipped then the cycle solution started from the model's initial conditions instead of from the last state of the previous cycle (#3708)
• Fixed a bug where the lumped thermal model conflates cell volume with electrode volume (#3707)
• Reverted a change to the coupled degradation example notebook that caused it to be unstable for large numbers of cycles (#3691)
• Fixed a bug where simulations using the CasADi-based solvers would fail randomly with the half-cell model (#3494)
• Fixed bug that made identical Experiment steps with different end times crash (#3516)
• Fixed bug in calculation of theoretical energy that made it very slow (#3506)
• The irreversible plating model now increments f"{Domain} dead lithium concentration [mol.m-3]", not f"{Domain} lithium plating concentration [mol.m-3]" as it did previously. (#3485)

Optimizations

• Updated jax and jaxlib to the latest available versions and added Windows (Python 3.9+) support for the Jax solver (#3550)

Breaking changes

• The parameters GeometricParameters.A_cooling and GeometricParameters.V_cell are now automatically computed from the electrode heights, widths and thicknesses if the "cell geometry" option is "pouch" and from the parameters "Cell cooling surface area [m2]" and "Cell volume [m3]", respectively, otherwise. When using the lumped thermal model we recommend using the "arbitrary" cell geometry and specifying the parameters "Cell cooling surface area [m2]", "Cell volume [m3]" and "Total heat transfer coefficient [W.m-2.K-1]" directly. (#3707)
• Dropped support for the [jax] extra, i.e., the Jax solver when running on Python 3.8. The Jax solver is now available on Python 3.9 and above (#3550)

v24.1rc2

Bug fixes

• Fixed a bug that lead to a ShapeError when specifying "Ambient temperature [K]" as an Interpolant with an isothermal model (#3761)