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Working with equations : Functions


Simile provides a large number of built-in functions that can be used in mathematical expressions. These include standard mathematical functions, such as log(…) as well as functions specific to Simile.

Some functions have one or more arguments (in brackets, after the function name). Others, such as the time() function, which returns the current simulation time, do not. You must still write the brackets after the function name, even if there are no arguments. This indicates that the name is a function name.

For most functions, the arguments are scalar values, i.e. a single quantitative value. In some cases, an argument is expected to be some other type of data structure, such as a Boolean value (true or false), or an array or list (such as the sum(…) function, which returns the sum of the values in an array or list.


It is possible to include user-defined functions. These can be specific to modelling in a restricted domain (such as plant physiology), so it will be possible for researchers in a particular community to build up and share common libraries of functions. 

Two special functions are graph(…) and table(…), which relate to a graphically-represented and a tabulated relationship respectively. These can be included in an expression like any other function, but differ from other functions in that the result they return for a given input value can be different in each equation in which it is used: it's definition is local to the equation, rather than being universally defined (like the log(…) function, for example).

In: Contents >> Working with equations >> Components of an equation