commonSense project

Hereunder, I list the classes that I have derived. When not mentioned here, it are the original classes but relocated due to programming requirements, such as inherited protected variables and methods.

Derived classes

• Matrix : This is an extended copy of the RealMatrixImpl impementation of commons.math . The main differences are:
  • "0-based" in stead of "1-based" indexing. The RealMatrixImpl tries to be consistent with the mathematical notation and that is often the "1-based" indexing. However, JAVA uses a "0-based" indexing system for their (1d, 2d, etc) arrays and that makes more sense (and less error prone) than when using both systems combined. Beyond that, it reduced the computation time of some of the packages I developed. (This was implemented in the commons.math class several days after I created this class.)
  • No implemented interface with many different methods.
  • Implemented several subMatrix methods, as well as getRowMatrix , getColumnMatrix and toSquareString methods.
• Variances : Implementation of Variance such that it does enable to calculate Sample (dividing by N-1) as well as Population (dividing by N) variances. I think this is better than defining two separate classes for both type of variances.

Added classes

• Distances : Matrix based class to calculate euclidian and mahalanobis distances.
• SpecialMatrices : This class is the home of several special type matrices.
  • SSCP (Sum-of-Squares-Cross-Product) matrix
  • Difference matrices based on row or colum averages
  • Covariance matrix
  • Correlation matrix
  Sample (co-)variance estimates are used by default, but population (co-) variance estimates can be requested by using the extended methods.