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 Other toolboxes required pad_array Pads an array with zeroes in a similar way to padarray in MATLAB. none Helper functions
 This is a helper function that only exists to aid other functions in QETLAB. If you are an end-user of QETLAB, you likely will never have a reason to use this function.

pad_array is a function that takes an array and either prepends or postpends a number of zeroes specified by the function call.

## Argument descriptions

• ARR: The array which will have zeroes padded onto it.
• PAD_NUM: The number of zeroes to either prepend or postpend onto ARR. This must be a non-negative integer.
• DIR: An integer specifying whether to prepend or postpend the zeroes onto ARR. 0 means to prepend, 1 means to postpend, and any other number will throw an error.

## Examples

A basic example of how pad_array works.

```>> arr = [1,2,3,4];

ans =

0     0     1     2     3     4

ans =

1     2     3     4     0     0```

## Notes

This function is only meant to simplify code within other functions without the need to install the image processing package of MATLAB or Octave-Forge. Note that this function only pads with zeroes. If other numbers are required, please use the `padarray' function within the image processing toolbox of MATLAB or Octave-Forge.

## Source code

Click on "expand" to the right to view the MATLAB source code for this function.

1. `%%  IDEN  Computes a sparse or full identity matrix`
2. `%   This function has two required arguments:`
3. `%     DIM: the number of rows (or columns) of the identity matrix`
4. `%     SP: a flag (1 or 0)`
5. `%`
6. `%   ID = iden(DIM,SP) returns the DIM-by-DIM identity matrix. If SP = 0`
7. `%   then ID will be full. If SP = 1 then ID will be sparse.`
8. `%`
9. `%   Only use this function within other functions to easily get the correct`
10. `%   identity matrix. If you always want either the full or the sparse`
11. `%   identity matrix, just use MATLAB's built-in eye or speye function.`
12. `%`
13. `%   URL: http://www.qetlab.com/iden`
14. ` `
15. `%   requires: nothing`
16. `%   author: Nathaniel Johnston (nathaniel@njohnston.ca)`
17. `%   package: QETLAB`
18. `%   last updated: November 28, 2012`
19. ` `
20. `function id = iden(dim,sp)`
21. ` `
22. `if(sp)`
23. `    id = speye(dim);`
24. `else`
25. `    id = eye(dim);`
26. `end`