The purpose of the PopTools program is to emulate a subset of the analytical and statistical methods that are available in advanced mathematical and statistical programs (eg, Mathematica, Matlab, R, S-Plus, Genstat). These programs are more flexible and powerful than PopTools, but are not generally available to students (or impoverished ecologists), and also require some knowledge of programming to use them properly. PopTools allows the construction, analysis, and simulation of quite complex models in a simple spreadsheet format. The only programming required is the ability to construct formulas in Excel — although to use the full potential of PopTools, and Excel worksheets in general, you might want to learn how to use array formulas.

• Documentation

Eigenvalue

Eigenvalues and diagonalization were discovered in 1926 by Augustin Louis Cauchy in the process of finding normal forms for quadratic functions. (An early calculation equivalent to diagonalization is attributed to Johan de Witt in 1660.)