Expression | str | This is the actual string containing the analytical function f(R, Theta), where R is the radial distance from pixel (X,Y) and Theta is the angle in degrees. The general methematical syntax is based on Python language. The variable arguments are passed labelled with a $ char as specified in PEP 292 (http://www.python.org/dev/peps/pep-0292/). Example | |