### 11.12 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.
`deprecated`
  Out-of-date functions which will eventually be removed from Octave.
`elfun`
  Elementary functions, principally trigonometric.
`@ftp`
  Class functions for the FTP object.
`general`
  Miscellaneous matrix manipulations, like `flipud`, `rot90`, and `triu`, as well as other basic functions, like `ismatrix`, `nargchk`, etc.
`geometry`
  Functions related to Delaunay triangulation.
`help`
  Functions for Octave's built-in help system.
`image`
  Image processing tools. These functions require the X Window System.
`io`
  Input-output functions.
`linear-algebra`
  Functions for linear algebra.
`miscellaneous`
  Functions that don't really belong anywhere else.
`optimization`
  Functions related to minimization, optimization, and root finding.
`path`
  Functions to manage the directory path Octave uses to find functions.
`pkg`
  Package manager for installing external packages of functions in Octave.
`plot`
  Functions for displaying and printing two- and three-dimensional graphs.
`polynomial`
  Functions for manipulating polynomials.
`prefs`
  Functions implementing user-defined preferences.
`set`
  Functions for creating and manipulating sets of unique values.
`signal`
  Functions for signal processing applications.
`sparse`
  Functions for handling sparse matrices.
`specfun`
  Special functions such as `bessel` or `factor`.
`special-matrix`
  Functions that create special matrix forms such as Hilbert or Vandermonde matrices.
`startup`
  Octave's system-wide startup file.
`statistics`
  Statistical functions.
`strings`
  Miscellaneous string-handling functions.
`testfun`
  Functions for performing unit tests on other functions.
`time`
  Functions related to time and date processing.