### 11.13 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.

`@ftp`

  Class functions for the FTP object.

`+containers`

  Package for the containers classes.

`audio`

  Functions for playing and recording sounds.

`deprecated`

  Out-of-date functions which will eventually be removed from Octave.

`elfun`

  Elementary functions, principally trigonometric.

`general`

  Miscellaneous matrix manipulations, like `flipud`, `rot90`, and `triu`, as well as other basic functions, like `ismatrix`, `narginchk`, etc.

`geometry`

  Functions related to Delaunay triangulation.

`gui`

  Functions for GUI elements like dialog, message box, etc.

`help`

  Functions for Octave’s built-in help system.

`image`

  Image processing tools. These functions require the X Window System.

`io`

  Input-output functions.

`java`

  Functions related to the Java integration.

`linear-algebra`

  Functions for linear algebra.

`miscellaneous`

  Functions that don’t really belong anywhere else.

`ode`

  Functions to solve ordinary differential equations (ODEs).

`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.