# Normalize cols

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 Other toolboxes required normalize_cols Scales the columns of a matrix to have norm 1 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.

normalize_cols is a function that scales each column of a matrix so that it has norm 1. That is, each column of the matrix is divided by its norm.

## Syntax

• Y = normalize_cols(X)

## Argument descriptions

• X: A matrix to have its columns normalized.

## Examples

```>> X = [1 0 1;0 2 1i;0 0 -1;0 0 -1i]

X =

1.0000                  0             1.0000
0             2.0000                  0 + 1.0000i
0                  0            -1.0000
0                  0                  0 - 1.0000i

>> normalize_cols(X)

ans =

1.0000                  0             0.5000
0             1.0000                  0 + 0.5000i
0                  0            -0.5000
0                  0                  0 - 0.5000i```

## Source code

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

1. `%%  NORMALIZE_COLS    Scales the columns of a matrix to have norm 1`
2. `%   This function has one required argument:`
3. `%     X: a matrix`
4. `%`
5. `%   Y = normalize_cols(X) is the same as X, except each of its columns has`
6. `%   been divided by its length.`
7. `%`
8. `%   URL: http://www.qetlab.com/normalize_cols`
9. ` `
10. `%   requires: nothing`
11. `%   author: Nathaniel Johnston (nathaniel@njohnston.ca)`
12. `%   package: QETLAB`
13. `%   last updated: January 2, 2013`
14. ` `
15. `function Y = normalize_cols(X)`
16. ` `
17. `Y = X./repmat(sqrt(sum(abs(X).^2,1)),size(X,1),1);`