Release 4.18

This is a performance and bug-fix release.

• Improved performance of AbsorbingLS.fit by deferring some operations.
• Added support for the method available in PyHDFE in AbsorbingLS. These methods can only be used when the variables absorbed are categorical (i.e., fixed-effects only) and when the model is unweighted.
• Added alternative measures of R-squared using the squared correlation. See PanelResults.corr_squared_overall, PanelResults.corr_squared_within, and PanelResults.corr_squared_between.
• Added a clustered covariance estimator (ClusteredCovariance) for system regressions.
• Fixed a bug in kernel_optimal_bandwidth which used incorrect values for a tuning parameter in the bandwidth estimation for the Parzen and Quadratic Spectral kernels.

Release 4.17

This is a minor release that corrects multiple incorrect type definitions.

Release 4.16

This release being two features and some bug fixes:

• Added FamaMacBethResults which exposes the set of estimated regression coefficients used to construct the model estimator.
• Added typing to all functions
• Refactored code to statically type with mypy and fixed some subtle bugs

Release 4.15.4

This release fixes a small number of bugs, adds new measure of model fit, and provides some essential maintenance:

• Blackened the code.
• Added McElroy's and Berndt's measures of system fit.
• Removed support for Python 3.5 inline with NEP-29.
• Fixed a bad test that only appeared when packaging from 4.15.3.

Release 4.15.3

This release fixes a small number of bugs, adds new measure of model fit, and provides some essential maintenance:

• Blackened the code.
• Added McElroy's and Berndt's measures of system fit.
• Removed support for Python 3.5 inline with NEP-29.
• Fixed a packing error in 4.15.2

Release 4.15.2

This release fixes a small number of bugs, adds new measure of model fit, and provides some essential maintenance:

• Blackened the code.
• Added McElroy's and Berndt's measures of system fit.
• Removed support for Python 3.5 inline with NEP-29.
• Fixed a packing error in 4.15.1

Release 4.15.1

This release fixes a small number of bugs, adds new measure of model fit, and provides some essential maintenance:

• Blackened the code.
• Added McElroy's and Berndt's measures of system fit.
• Removed support for Python 3.5 inline with NEP-29.
• Fixed a packing error in 4.15

Release 4.15

This release fixes a small number of bugs, adds new measure of model fit, and provides some essential maintenance:

• Blackened the code.
• Added McElroy's and Berndt's measures of system fit.
• Removed support for Python 3.5 inline with NEP-29.

Release 4.14

This release fixes a small number of bugs and provides some essential maintenance:

• Fixed issue where datasets were not installed with wheels.
• Switched to property-cached to inherit cached property from property.
• Removed all use pandas.Panel.

Release 4.13

This is a feature and bug release.

• Added AbsorbingLS which allows a large number of variables to be absorbed. This model can handle very high-dimensional dummy variables and has been tested using up to 1,000,000 categories in a data set
  with 5,000,000 observations.
• Fixed a bug when estimating weighted panel models that have repeated observations (i.e., more than one observation per entity and time id).
• Added drop_absorbed option to PanelOLS which automatically drops variables that are absorbed by fixed effects.
• Added optional Cythonized node selection for dropping singletons
• Added preconditioning to the dummy variable matrix when use_lsmr=True in fit. In models with many effects, this can reduce run time by a factor of 4 or more.