Heterogeneous Agents Resources and toolKit (HARK)

This release has many small improvements and fixes to existing HARK capabilities, listed below under Minor Changes. It also includes expanded and improved documentation/learning materials in examples/Gentle-Intro. To copy those example notebooks into a local working directory for easy use, simply execute these two commands and then follow the prompts: from HARK import install_examples install_examples() Four new consumption-saving models have been added, listed below under Major Changes. There are some breaking changes: TimeVaryingDiscreteDistribution has been removed; use IndexDistribution instead, and see #1592. FixedPortfolioShareRiskyAssetConsumerType is removed, but now incorporated as RiskyAssetConsumerType with PortfolioBool=False. Default behavior of latter class is unchanged; see #1607. The content of HARK.parallel has been moved to HARK.core, and the former is deprecated. Import from HARK.core and see #1614. parse_ssa_life_table now returns one fewer survival probability by default, to match output length of parse_income_spec; pass terminal=True to restore old behavior. Argument min_age has been renamed to age_min for consistency. See #1629. The parameter tau in RiskyContribModel has been renamed to WithdrawTax to match HARK notation style; see #1639. Simulation method get_Rfree() has been renamed to get_Rport(), but no functional changes; see #1646. The parameter DeprFac has been renamed to DeprRte to reflect its actual usage. All distributions now default to using a random seed if none is provided. If your code relied on HARK defaulting to a specific seed, it will not reproduce exactly. See #1641. The function apply_flat_income_tax has been removed, but it has not been used at all since 2016. Content from ConsLabeledModel has been split up into files in the Labeled submodule. See #1684. Major Changes Basic health investment model added in new module ConsHealthModel. #1567 Extensive margin medical care choice model added to ConsMedModel. #1595 TRP-style wealth-in-utility model without portfolio choice added in new module ConsWealthUtilityModel. #1634 "Capitalist spirit" style wealth-in-utility model added in new module ConsWealthUtilityModel. #1634 Minor Changes Fixed terminal solution initialization in IndShockConsumerTypeFast for proper numba compatibility, added CRRA=1 validation with clear error message, and expanded test coverage. #1649 Turns off use_infimum feature in ConsIndShock solver because it did not work properly when vFunc=True #1589 Consolidates TimeVaryingDiscreteDistribution into IndexDistribution. For time-varying discrete behavior, use IndexDistribution(distributions=[...]). #1592 Krusell-Smith model guide added to documentation. #1594 Added additional options and simplified syntax for non-default constructors when instantiating agents. #1591 Added options for custom indexer and pre-computation of coefficients to LinearInterp. #1593 Fixed bug that prevented combine_indep_dstn from working with Bernoulli distributions. #1581 Introductory / instructional notebooks significantly expanded. #1597 Lognormal discrete approximation math has been simplified. #1598 Directory structure for consumption-saving examples regularized. #1596 Fixed share model has been combined with RiskyAssetConsumerType's PortfolioBool=False option. #1607 Deprecate HARK.parallel, moving the three functions there to HARK.core. #1614 Test coverage expanded to cover almost all content #1606 #1610 #1617 #1619 #1623 #1624 #1625 #1626 #1628 #1684 Consumption-saving models now aliased at HARK.models and HARK.ConsumptionSaving; some calibration tools also aliased at HARK.Calibration #1629 AgentType.solve() can be passed postsolve=False to skip post-processing call to post_solve(). #1631 The /examples directory can be copied to a directory of user's choice with HARK.install_examples() #1630 Improved and expanded features for Parameters class in HARK.core #1627 Fixed the representation of the terminal period solution in ConsPrefShock #1638 Renamed tau to WithdrawTax in RiskyContribModel #1639 Valid bounds checking on make_grid_exp_mult #1640 Ensure utility functions return NaN for negative consumption #1640 Fixed a bug with resetting the RNG of IndexDistributions, restoring replicability of simulations #1643 Legacy simulation methods now use get_Rport() instead of get_Rfree() #1646 Fixed a bug that occured when changing an AgentType's AgentCount attribute after simulating #1647 Add describe_distance() method to MetricObject, generating text description of how "distance" is calculated for an object #1648 Default behavior of seeds for distribution classes has been revised. #1641 Terminal solution representation for the "fast" solvers (using numba) has been cleaned up. #1649 Refactored ConsLabeledModel to use new HARK.Labeled subpackage with modular architecture (config, factories, transitions, solvers, solution, agents). Added comprehensive input validation, runtime warnings for numerical issues, and expanded test coverage. #1650