MADlib Release Notes
--------------------

These release notes contain the significant changes in each MADlib release,
with most recent versions listed at the top.

A complete list of changes for each release can be obtained by viewing the git
commit history located at https://github.com/madlib/madlib/commits/master.

Current list of bugs and issues can be found at http://jira.madlib.net.

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MADlib v0.6

Release Date: 2013-Apr-01

New Features / Improvements:
* Generic cross-validation:
    - Support for k-fold cross-validation of any supervised learning
      algorithm
* Heteroskedasticity of linear regression
    - Support for calculating heteroskedasticity via Breusch-Pagan test
* Grouping support for linear regression
    - Support for linear regression on each group of data grouped by
      one or multiple columns
* Grouping support for logistic regression
    - Refactor of logistic regression code
    - Support for logistic regression on each group of data grouped by
      one or multiple columns
    - Grouping support is added to the convex optimization framework
* LDA:
    - Improved performance and scalability (MADLIB-480)
* Elastic net regularization for both linear and logistic regressions
    - Support FISTA and IGD optimizers
* Summary function
    - Support for an overview of data table
* Eigen package upgrade
    - Now Eigen 3.1.2 is used by MADlib v0.6
* Unit testing framework:
    - A new unit testing framework is added for C++ abstraction layer

Bug Fixes:
* C++ abstraction layer:
    - Improved handling of NULL values in the input array (MADLIB-773)
* Naive Bayes:
    - Improved the handling of NULL values. (MADlib-749) 

Known Issues:

* K-means:
    - K-means crashes on some datasets, when the dimensionality of the points is not uniform on the data set. (MADlib-789) 

* Distribution Functions: 
    - Certain quantile functions will abort their session on invalid input. (MADlib-786) 

* Multinomial Logistic Regression:
    - Signs of coefficient outputs are inconsistent with other tools like R and Stata. (MADlib-785) 


--------------------------------------------------------------------------------
MADlib v0.5

Release Date: 2012-Nov-15

Bug Fixes:
* K-means:
    - Improved handling of invalid arguments (MADLIB-359, 361)
* Sketch-based estimators:
	  - Addressed security vulnerability (MADLIB-630)

New Features / Improvements:
* Association Rules (Apriori):
    - Improved reporting output format for better usability (MADLIB-411)
	  - Significant improvement in performance (MADLIB-638)
* C++ (Database) Abstraction Layer:
    - Extension to support modular transition states (MADLIB-499)
    - Extension to support functions returning set of values (MADLIB-638)
* Conditional Random fields:
    - Support for Linear Chain Conditional Random Fields for NLP (MADLIB-628)
* Decision Tree:
    - Improved performance for C4.5 and Random forests (MADLIB-605)
    - Improved encoding (MADLIB-590)
* Infrastructure:
    - Convex optimization framework
* K-means:
    - Code refactoring and Improved performance
      (MADLIB-454, MADLIB-522, MADLIB-678)
    - Silhouette function for k-means (MADLIB-681)
* Low-rank Matrix Factorization
    - New module
* Logistic Regression:
    - Support for Multinomial Logistic Regression (MADLIB-575)
* Naive Bayes
    - Significant improvement in performance (MADLIB-611, 619, 626)
* Regression Analysis:
    - Support for Cox Proportional Hazards test (MADLIB-576)
* Sampling
    - Added weighted sampling of a single row (MADLIB-584)
* SVD Matrix Factorization:
    - Improved performance (MADLIB-578)

Documentation:
* Conditional Random Fields:
    - Example added for CRF module (MADLIB-731)
* SVD Matrix Factorization:
    - Incremental-gradient SVD algorithm (MADLIB-572)

Known issues:
* Multinomial Logistic Regression:
    - Number of independent variables cannot exceed 65535 (MADLIB-665)
* Naive Bayes:
    - Current implementation of Naive Bayes is only suitable for
        categorical attributes (MADLIB-679)
    - NULL input values not accepted for attributes (MADLIB-614)
    - NULL probabilities given for test set values not seen in
      training set (MADLIB-523)

--------------------------------------------------------------------------------
MADlib v0.4.1

Release Date:  2012-Aug-9

Bug Fixes:
* PGXN:
    - Fixed installation problem that could occur on some platforms (MADLIB-589)

New Features/Improvements:
* C++ Abstraction Layer:
    - Increased ABI compatibility across multiple Greenplum versions
      (MADLIB-606)
* Hypothesis Tests:
    - Tests that are not implemented as ordered aggregates are now also
      installed on PostgreSQL 8.4 and Greenplum 4.0.

--------------------------------------------------------------------------------
MADlib v0.4

Release Date:  2012-Jun-18

Bug Fixes:
* Association Rules:
    - assoc_rules() now uses schema-qualified function calls (MADLIB-435)
* Decision Trees:
    - Enhanced correctness (MADLIB-409, 502, 503)
    - Improved handling of invalid arguments (MADLIB-331)
* k-Means:
    - Improved handling of invalid arguments (MADLIB-336, 364, 459)
* PLDA:
    - Improved robustness (MADLIB-474)
* Sparse Vectors:
    - svec_sfv() now uses locale-aware sorting (MADLIB-457)
    - Operators now install to MADlib schema (MADLIB-470)

New Features/Improvements:
* C++ Abstraction Layer:
    - Support for "function pointers" (MADLIB-370)
    - Support for sparse vectors (MADLIB-371)
    - Support for more Eigen (linear algebra) types (MADLIB-533)
* Decision Trees:
    - Code refactoring and optimization (MADLIB-410, 476, 504, 509)
    - Documentation improvments (MADLIB-507)
    - Output table now contains unencoded information (MADLIB-434)
    - Enhance the missing value handling for continuous features (MADLIB-493)
* Hypothesis Tests:
    - Pearson chi-square test (MADLIB-390)
    - One- and two-sample t-Tests (MADLIB-391)
    - F-test (MADLIB-392)
    - Mann-Whitney U-test (MADLIB-393)
    - Kolmogorov-Smirnov test (MADLIB-394)
    - Wilcoxon-Signed-Rank test (MADLIB-405)
    - One-way ANOVA (MADLIB-406)
* PostgreSQL Extensibility:
    - Support for CREATE EXTENSION in PostgreSQL >= 9.1 (MADLIB-316)
    - Availability on PGXN (MADLIB-334)
* Probability Functions:
    - Wrap all distribution functions implemented by Boost (MADLIB-412)
    - Wrap Kolmogorov distribution function from CERN ROOT project (MADLIB-413)
* Random Forests:
    - New module (MADLIB-419)
* Support:
    - Add elementary matrix/vector functions (e.g., norm/distances etc.)
      (MADLIB-532)
* Viterbi Feature Extraction:
    - New module (MADLIB-478)

Known issues:
    - svec_sfv() does not support collations, as introduced with PostgreSQL 9.1
      (MADLIB-558)
    - Invalid arguments are not always guaranteed to be handled gracefully and
      may lead to confusing error messages (MADLIB-28, 359, 361, 363)

--------------------------------------------------------------------------------
MADlib v0.3

Release Date:  2012-Feb-9

New features:
* Installer:
    - Single installer package targeting all supported DBMSs per OS (MADLIB-218)
* C++ Abstraction Layer:
    - Switched from using Armadillo to using Eigen for linear-algebra
      operations, thereby eliminating the dependency on LAPACK/BLAS (MADLIB-275)
    - Reimplemented as a template library for performance improvements
      (MADLIB-295)
* Decision Trees:
    - Major update
    - Now supports multiple split criteria (information gain, gini, gain ratio)
    - Now supports tree pruning using a validation set to address over fitting
    - Now supports additional functions for tree output
    - Now supports continuous features in addition to categorical features
    - Additional support for handling null values
    - Improved scalability and performance
* k-Means Clustering:
    - Now handles any input that is convertible to SVEC. (MADLIB-42)
    - Multiple distance functions (L1-norm, L2-norm, cosine similarity, Tanimoto
      similarity) (MADLIB-43)
    - Supports multiple seedings methods (kmeans++, random, user-specified list
      of centroids)
    - Replaced goodness of fit with the (simplified) Silhouette coefficient
      (MADLIB-45)
    - New run-time parameters (MADLIB-47)
* Linear Regression:
    - Major speed improvement
* Logistic Regression:
    - Major speed improvement
    - Now handles any input that is convertible to BOOLEAN (dependent variable)
      or DOUBLE PRECISION[] (independent variables). (MADLIB-283)
    - An under-/overflow safe version to evaluate the (usual) logistic function,
      for scoring logistic regression (MADLIB-271)
    - A third optimizer: Incremental-gradient-descent (MADLIB-303)
* Support:
    - For Greenplum <= 4.2.0, added a workaround for INSERT INTO in the same way
      as the existing CREATE TABLE AS workaround. This workaround is not needed
      in Greenplum >= 4.2.1 any more. (MADLIB-265)
    - Function version() returns Madlib build information (MADLIB-309)

Bug fixes:
* Sparse vectors:
    - Fixed sparse-vector type case problems (MADLIB-282, MADLIB-305)
    - Fixed a situation where using svec_svf() could cause a segmentation fault
      (MADLIB-350)
    - Increased compatibility with internal PostgreSQL conventions (MADLIB-257)
* Logistic regression:
    - Handle numerical instability more gracefully (MADLIB-343, MADLIB-345)
    - Handle unexpected inputs more gracefully (MADLIB-284, MADLIB-344)
    - Fixed "Random variate x is nan, but must be finite" issue (MADLIB-356)

Known issues:
    - Decision Trees not supported on Greenplum 4.0 (MADLIB-346, MADLIB-347)
    - K-means: the error '"nan" does not exist' may be raised when input vectors
      contain NaN. (MADLIB-364)
    - Association Rules require the madlib schema to be in the search path
      (MADLIB-353)
    - Invalid arguments are not always guaranteed to be handled gracefully and
      may lead to confusing error messages (MADLIB-28, 336, 359, 361, 363, 364)

--------------------------------------------------------------------------------
MADlib v0.2.1beta

Release Date: 2011-Sep-14

General changes:
* numerous improvements to the C++ abstraction layer:
    - code clean-up
    - fixed issue where incorrect values were returned when used with
      debug builds of PostgreSQL/Greenplum (MADLIB-253)
    - fixed issue where returning arrays to PostgreSQL/Greenplum could lead
      to a crash (MADLIB-250)
    - allocated memory is now 16-byte aligned for improved stability and
      performance (MADLIB-236)
* compiling with advanced warnings enabled by default now
* all C/C++ code now free of warnings. On gcc <= 4.6, there might still be
  warnings due to "unclean" macros in DBMS header files (MADLIB-228)
* prepared Solaris support in a later release (MADLIB-204)
    - added support for Sun Compiler in CMake build script
    - fixed all compilation errors with Sun compiler
* added UDF to mimic "CREATE TABLE AS ...", as a workaround for a Greenplum
  issue (MADLIB-241). Included this as GP Compatibility module.
* madpack utility:
    - dropped madpack dependency on PygreSQL (MADLIB-217)
    - improved security in madpack install-check (MADLIB-229)
    - fixed bashism in madpack (MADLIB-222)
    - fixed install-check not running on non-default schema (MADLIB-251)

Modules/methods:
* SVM (kernel_machines):
    - fixed cumulative error count in svm_cls_update() function
    - improved memory management in SVM module
* Linear regression (regress):
    - fixed unexpected behavior for some edge cases (MADLIB-214)
    - fixed crashing with huge number of independent vars (MADLIB-250)
* Logistic regression (regress):
    - added support for arbitrary expressions for dep./indep. variables, not
      just column names (MADLIB-255)
* Quantile:
    - fixed quantile() function to be exact
    - added simple version for small data sets
* Sparse Vectors:
    - added check for sorted dictionary to svec_sfv (MADLIB-187)
* Decision Tree (decision_tree):
    - now can be run multiple times in one session (MADLIB-156)

Known issues:
* non-unified API for several SQL UDFs (MADLIB-208)
* performance of the conjugate-gradient optimizer in logistic regression
  can be very poor (MADLIB-164)

--------------------------------------------------------------------------------
MADlib v0.2.0beta

Release Date: 2011-Jul-8

General changes:
* new build and installation framework based on CMake
* new C++ abstraction layer for easy and secure method development
* new database installation utility (madpack)

Modules/methods:
* new: Association Rules (assoc_rules)
* new: Array Operators (array_ops)
* new: Decision Tree (decision_tree)
* new: Conjugate Gradient (conjugate_gradient)
* new: Parallel LDA	(plda)
* improved: all methods from previous release

Known issues:
* non-unified API for several SQL UDFs (MADLIB-208)
* running decision tree more than once in one session fails (MADLIB-156)
* performance of the conjugate-gradient optimizer in logistic regression
  can be very poor (MADLIB-164)
* svec_sfv function doesn't check for sorted dictionary (MADLIB-187)

--------------------------------------------------------------------------------
MADlib v0.1.0alpha

Release Date: 2011-Jan-31

Initial release.

Included modules/methods:
* Naive-Bayes Classification (bayes)
* k-Means Clustering (kmeans)
* Support Vector Machines (kernel_machines)
* Sketch-based Estimators (sketch)
* Sketch-based Profile (data_profile)
* Quantile (quantile)
* Linear & Logistic Regression (regress)
* SVD Matrix Factorisation (svdmf)
* Sparse Vectors (svec)

--------------------------------------------------------------------------------
MADlib v0.1.0prerelease

Release date: 2011-Jan-25

Demo release.