The R You Ready blog posed an interesting problem. Essentially, you have a vector that contains n(n+1)/2 elements, and you want to pack those elements into the upper left triangular portion of a matrix. For example, if your data are proc iml; /** vector v is given: ncol(v) = n(n+1)/2 for
When programmers begin learning a new computer language, the first program they write is often one that prints the text “Hello, World!” Successfully writing a Hello World program assures the programmer that the software is successfully installed and that all necessary features are working: parsers, compilers, linkers, and so on.
I just returned home from Vancouver, British Columbia, where I attended the 2010 Joint Statistical Meetings (JSM). I heard that more than 5,300 statisticians attended this year, including about 40 or so from SAS. I stayed busy. I gave a presentation on techniques for visualizing time series, gave a two-hour