The DO Loop
Statistical programming in SAS with an emphasis on SAS/IML programs
In statistical programming, we often assume that the data are stored in a matrix or a data set and can be read at will. For example, if you want to compute a sample mean or standard deviation, you simply pass a vector to a built-in function, and the software spits
This is the last article in a series about the nonnegative matrix factorization (NMF). In this article, I run and visualize an NMF analysis of the Scotch whisky data and compare it to a principal component analysis (PCA). Previous articles in the series provide information about the whisky data, the
The classical singular value decomposition (SVD) has a long and venerable history. I have described it as a fundamental theorem of linear algebra. Nevertheless, the mathematical property that makes it so useful in general (namely, the orthogonality of the matrix factors) also makes it less useful for certain applications. In