Handle used in calling functions indirectly

`handle = @functionname`

handle = @(arglist)anonymous_function

`handle = @functionname`

returns
a handle to the specified MATLAB^{®} function.

A function handle is a MATLAB value that provides a means
of calling a function indirectly. You can pass function handles in
calls to other functions (often called *function functions*).
You can also store function handles in data structures for later use
(for example, as Handle Graphics callbacks). A function handle is
one of the standard MATLAB data types.

At the time you create a function handle, the function you specify must be on the MATLAB path and in the current scope of the code creating the handle. For example, you can create a handle to a local function as long as you do so from within the file that defines that local function. This condition does not apply when you evaluate the function handle. You can, for example, execute a local function from a separate (out-of-scope) file using a function handle. This requires that the handle was created by the local function (in-scope).

`handle = @(arglist)anonymous_function`

constructs
an anonymous function and
returns a `handle`

to that function. The body of
the function, to the right of the parentheses, is a single MATLAB statement
or command. `arglist`

is a comma-separated list of
input arguments. Execute the function by calling it by means of the
function handle, `handle`

.

The following example creates a function handle for the `humps`

function
and assigns it to the variable `fhandle`

.

fhandle = @humps;

Pass the handle to another function in the same way you would
pass any argument. This example passes the function handle just created
to `fminbnd`

, which then minimizes over the interval ```
[0.3,
1]
```

.

x = fminbnd(fhandle, 0.3, 1) x = 0.6370

The `fminbnd`

function evaluates the `@humps`

function
handle. A small portion of the `fminbnd`

file is
shown below. In line 1, the `funfcn`

input parameter
receives the function handle `@humps`

that was passed
in. The statement, in line 113, evaluates the handle.

1 function [xf,fval,exitflag,output] = ... fminbnd(funfcn,ax,bx,options,varargin) . . . 113 fx = funfcn(x,varargin{:});

The statement below creates an anonymous function that finds
the square of a number. When you call this function, MATLAB assigns
the value you pass in to variable `x`

, and then uses `x`

in
the equation `x.^2`

:

sqr = @(x) x.^2;

The `@`

operator constructs a function handle
for this function, and assigns the handle to the output variable `sqr`

.
As with any function handle, you execute the function associated with
it by specifying the variable that contains the handle, followed by
a comma-separated argument list in parentheses. The syntax is

fhandle(arg1, arg2, ..., argN)

To execute the `sqr`

function defined above,
type

a = sqr(5) a = 25

Because `sqr`

is a function handle, you can
pass it in an argument list to other functions. The code shown here
passes the `sqr`

anonymous function to the MATLAB `integral`

function to compute its integral
from zero to one:

integral(sqr, 0, 1) ans = 0.3333

This example creates a structure array of function handles `S`

and
then applies each handle in the array to the output of a `linspace`

calculation in one operation
using `structfun`

:

S.a = @sin; S.b = @cos; S.c = @tan; structfun(@(x)x(linspace(1,4,3)), S, 'UniformOutput', false) ans = a: [0.8415 0.5985 -0.7568] b: [0.5403 -0.8011 -0.6536] c: [1.5574 -0.7470 1.1578]

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