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User Defined Functions in MATLAB Part-4

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A MATLAB function that accepts another function as an input is called a function function. Function handles are used for passing functions to function functions. Syntax for function function is same as simple functions, but one or more input arguments will be function handles.
Multiple functions within one function file is called local function. Name of function file should be name of main function. Main function can be called from the command window or any other function. Local functions are typed in any order after the main function. Local functions are only visible to other functions in the same file.
A private function is a function residing in a sub directory with the name private. Private functions are visible only to functions in the parent directory.

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User Defined Functions in MATLAB Part-4

  1. 1. Function Function Local Function Private Function MOREON USERDEFINEDFUNCTION Shameer A Koya http://electricalenggtutorial.blogspot.com
  2. 2. A function handle is a data type that stores an association to a function. the functions can be built-in, user defined, or anonymous It is used to call a function indirectly. To make a function handle for built-in or user- defined function, put the @ symbol in front of function name fhandle = @functionname function handle for MATLAB ones function is @ones FUNCTION HANDLE
  3. 3. Typical uses are: Pass a function to another function (called function functions). Specify callback functions. (GUI programming) Construct handles to inline functions or anonymous functions. Call local functions from outside the main function USES OF FUNCTION HANDLE
  4. 4.  Anonymous function sqr = @(x) x.^2  Calling function indirect: function y = Sqr(x) y = x.^2; end f = @Sqr; a = 2; b = f(a); b = 4  Pass to another function z = integral(f,0,1); EXAMPLES
  5. 5. A MATLAB function that accepts another function as an input is called a function function Function handles are used for passing functions to function functions Syntax for function function is same as simple functions, but one or more input arguments will be function handles. FUNCTION FUNCTIONS
  6. 6.  From the previous example: z = quad(f,0,1); z = 0.33333  Calculate the integral for the interval specified. fzero(@sqr,-3,3)  Finds the zeros of the function with in the range  Can be used to plot the functions x = linspace(-3,3,100); figure; plot(x,f(x)) EXAMPLES
  7. 7.  Multiple functions within one function file  Name of function file should be name of main function.  Main function can be called from the command window or any other function.  Local functions are typed in any order after the main function.  Local functions are only visible to other functions in the same file. (They are not visible to the functions out side or command window). LOCAL FUNCTION (SUB-FUNCTION)
  8. 8. function [a, b, c] = basicmath(x, y) % basicmath is the main function. a = add(x,y); b = sub(x,y); c = mult(x,y); end function l = add(u,v) % add is a local function. l = u+v; end function m = sub(u,v) % sub is another local function. m = u-v; end function n = mult(u,v) % sub is another local function. n = u*v; end EXAMPLE
  9. 9.  A private function is a function residing in a subdirectory with the name private.  Private functions are visible only to functions in the parent directory.  They are useful when we want to limit the scope of a function.  You cannot call the private function from the command line or from functions outside the parent of the private folder. PRIVATE FUNCTIONS

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