2023-04-28: Version 0.1.15
* Updated.

2018-04-25: Version 0.1.14
* Error fixed.

2018-04-24: Version 0.1.13
* Demo for Sigma-K-means added.

2018-04-21: Version 0.1.12
* Sigma-K-means added.

2017-11-18: Version 0.1.11
* Minor problem fixed.

2017-11-18: Version 0.1.10
* New functionality added.

2017-09-25: Version 0.1.9
* Error fixed.

2017-09-03: Version 0.1.8
* New functions added.

2016-12-03: Version 0.1.7
* Reference fixed.

2016-12-02: Version 0.1.6
* Reference added.

2016-12-02: Version 0.1.5
* Running time fixed.

2016-12-01: Version 0.1.4
* New functions added.

2016-04-14: Version 0.1.3
* New functions added.

2015-10-03: Version 0.1.2
* Memory allocation error fixed.

2015-09-30: Version 0.1.1
* First version built.