Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of SAS/IML software. His areas of expertise include computational statistics, simulation, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS.
Many applications in mathematics and statistics require the numerical computation of the derivatives of smooth multivariate functions. For simple algebraic and trigonometric functions, you often can write down expressions for the first and second partial derivatives. However, for complicated functions, the formulas can get unwieldy (and some applications do not
An experienced SAS programmer recently switched to SAS Viya and asked how to discover what products are available on his version of Viya. We discussed a few older SAS 9 procedures, and I showed him a new Viya-specific way to get information about his version of SAS and his licensed
It is important to be able to detect whether a numerical matrix is symmetric. Some operations in linear algebra require symmetric matrices. Sometimes, you can use special algorithms to factor a symmetric matrix. In both cases, you need to test a matrix for symmetry. A symmetric matrix must be square.
