MATLAB Programming Fundamentals - MathWorks

Pass Function to Another Function

You can use function handles as input arguments to other functions, which are called

function functions. These functions evaluate mathematical expressions over a range of

values. Typical function functions include integral, quad2d, fzero, and fminbnd.

For example, to find the integral of the natural log from 0 through 5, pass a handle to the

log function to integral.

a = 0;

b = 5;

q1 = integral(@log,a,b)

q1 = 3.0472

Similarly, to find the integral of the sin function and the exp function, pass handles to

those functions to integral.

q2 = integral(@sin,a,b)

q2 = 0.7163

q3 = integral(@exp,a,b)

q3 = 147.4132

Also, you can pass a handle to an anonymous function to function functions. An

anonymous function is a one-line expression-based MATLAB® function that does not

require a program file. For example, evaluate the integral of x/(ex−1) on the range

[0,Inf]:

fun = @(x)x./(exp(x)-1);

q4 = integral(fun,0,Inf)

q4 = 1.6449

Functions that take a function as an input (called function functions) expect that the

function associated with the function handle has a certain number of input variables. For

example, if you call integral or fzero, the function associated with the function handle

must have exactly one input variable. If you call integral3, the function associated with

the function handle must have three input variables. For information on calling function

functions with more variables, see “Parameterizing Functions”.

13 Function Handles