### 13.10 Organization of Functions Distributed with Octave

Many of Octave's standard functions are distributed as function files. They are loosely organized by topic, in subdirectories of `octave-home/lib/octave/version/m`, to make it easier to find them.

The following is a list of all the function file subdirectories, and the types of functions you will find there.

`audio`
  Functions for playing and recording sounds.
`control`
  Functions for design and simulation of automatic control systems.
`elfun`
  Elementary functions.
`general`
  Miscellaneous matrix manipulations, like `flipud`, `rot90`, and `triu`, as well as other basic functions, like `ismatrix`, `nargchk`, etc.
`image`
  Image processing tools. These functions require the X Window System.
`io`
  Input-ouput functions.
`linear-algebra`
  Functions for linear algebra.
`miscellaneous`
  Functions that don't really belong anywhere else.
`plot`
  A set of functions that implement the Matlab-like plotting functions.
`polynomial`
  Functions for manipulating polynomials.
`set`
  Functions for creating and manipulating sets of unique values.
`signal`
  Functions for signal processing applications.
`specfun`
  Special functions.
`special-matrix`
  Functions that create special matrix forms.
`startup`
  Octave's system-wide startup file.
`statistics`
  Statistical functions.
`strings`
  Miscellaneous string-handling functions.
`time`
  Functions related to time keeping.