add changelog

CHANGELOG.md

@@ -1,25 +1,45 @@
 # Changelog
+
 All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.0.0]
+
+### Changed
+
+- Term frequency adjustments are now calculated directly from a term freqency lookup table making them more accurate
+- Term frequency adjustments are now part of the iterative EM estimation step, improving convergence
+- All internal calculations are changed to use bayes factors (match weights) rather than probabilities to make the maths simpler
+
+### Added
+
+- Splink now outputs `match_weight`, the log2(Bayes Factor) of the match score.
+- New `splink.charts.save_offline_chart` function that produces charts that work in airgapped environments with no internet connection
+- New `splink.cluster.clusters_at_thresholds` function that clusters are one or more match thresholds
+- The `splink.truth.roc_chart` function now allows several ROCS to be plotted on a single chart, to compare the accuracy of different models
+- Splink now includes an slower Python implementation of jaro_winkler, in case users are having trouble with the string similarity jar
+
+### Removed
+
+- Since term frequency adjustments are no longer an ex-post step, there's no longer a need for them to be calculated separately. Splink therefore no longer outputs `tf_adjusted_match_prob`. Instead, TF adjustments are included within `match_probability`
+
 ## [1.0.5]
 
 ### Fixed
 
-- Bug that meant default numerical case statements were not available.  See [here](https://github.com/moj-analytical-services/splink/issues/189).  Thanks to [geobetts](https://github.com/geobetts)
+- Bug that meant default numerical case statements were not available. See [here](https://github.com/moj-analytical-services/splink/issues/189). Thanks to [geobetts](https://github.com/geobetts)
 
 ### Changed
 
-- `m` and `u` probabilities are now reset to `None` rather than `0`  in EM iteration when they cannot be estimated
+- `m` and `u` probabilities are now reset to `None` rather than `0` in EM iteration when they cannot be estimated
 - Now use `_repr_pretty_` so that objects display nicely in Jupyter Lab rather than `__repr__`, which had been interfering with the interpretatino of stack trace errors
 
 ## [1.0.3] - 2020-02-04
 
-
-
 - Bug whereby Splink lowercased case expressions, see [here](https://github.com/moj-analytical-services/splink/issues/174)
+
 ## [1.0.2] - 2020-02-02
 
 ### Changed
@@ -39,34 +59,28 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - m and u history charts now display barchart correctly
 
 ## [1.0.0] - 2020-01-20
+
 ### Added
-- Charts now feature improved tooltips, and have a cleaner appearance.  Many are now zoomable
+
+- Charts now feature improved tooltips, and have a cleaner appearance. Many are now zoomable
 - Charts now display better in Jupyter Lab, especially the html file produced by `all_charts_write_html_file()`
 - `m` and `u` probabilities charts can now be produced from `Settings` objects
 - The user can now combine settings objects using `ModelCombiner from splink.combine_models`
-### Changed
 
+### Changed
 
 A number of **backwards incompatible** changes have been made for Splink 1.0.
 
-- The main `Splink` API is different.  Instead of `Splink(...,df=df)` for dedupe and `Splink(...,df_l=df_l,df_r=df_r)` for linking, the user provides an agument `df_or_dfs`, which is either a single DataFrame or a list of DataFrames.  This allows linking n>2 datasets.
+- The main `Splink` API is different. Instead of `Splink(...,df=df)` for dedupe and `Splink(...,df_l=df_l,df_r=df_r)` for linking, the user provides an agument `df_or_dfs`, which is either a single DataFrame or a list of DataFrames. This allows linking n>2 datasets.
 - When linking multiple dataframes, the user must now include a `source_dataset` column (default name `source_dataset`, configurable via `source_dataset_column_name` in the settings dict)
 - The `Params` class is now called `Model` in the `model.py` module.
 - The on-disk (json) format of the `Model` object has changed and is incompatible with `Params`
-- The new `Model` class now uses the same representation for parameters as the Settings object, reducing duplicate code.  Internal functions now have `settings` or `model` as function arguments, never both.
+- The new `Model` class now uses the same representation for parameters as the Settings object, reducing duplicate code. Internal functions now have `settings` or `model` as function arguments, never both.
 - Vega lite chart definitions now stored in json files in splink/files/chart_defs
 - All case statement generation functions are now consistently named, with all names starting `sql_gen_case_stmt_`
 - Fixed `case_statements.sql_gen_case_smnt_strict_equality_2` which previously behaved differently to all other case functions
 - All case statements now have a default threshold of exact equality on their top gamma level
 
-
-
 ### Fixed
 
 ### Removed
-
-
-
-
-
-