NDArray::identity

public static function identity(int $size): NDArray;

This function returns a square array, where the main diagonal consists of ones and all other elements are zeros. It takes a parameter $size which determines the number of rows and columns in the output array.

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Parameters

$size

Type long

• Number of rows and columns of the new square array of size ($size, $size)

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Return

Type - NDArray

• Return a new square array of size ($size, $size)

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Examples

Example 1

use \NDArray as nd;

$a = nd::identity(10);
print_r($a);

[[1, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 1, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 1, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 1, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 1, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 1, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 1, 0, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 1, 0],
 [0, 0, 0, 0, 0, 0, 0, 0, 0, 1]]

Example 2

use \NDArray as nd;

$a = nd::identity(0);
print_r($a);

[]

Example 3

use \NDArray as nd;

$a = nd::identity(-1);
print_r($a);

Fatal error: Uncaught Error: negative dimensions are not allowed in /src/test.php:4

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Exceptions

If $size is less than 0 a Fatal error will be raised

Fatal error: Uncaught Error: negative dimensions are not allowed in /src/test.php:4