Php Program to check if matrix is lower triangular
Given a square matrix and the task is to check the matrix is in lower triangular form or not. A square matrix is called lower triangular if all the entries above the main diagonal are zero.
Examples:
Input : mat[4][4] = {{1, 0, 0, 0},
{1, 4, 0, 0},
{4, 6, 2, 0},
{0, 4, 7, 6}};
Output : Matrix is in lower triangular form.
Input : mat[4][4] = {{1, 0, 0, 0},
{4, 3, 0, 1},
{7, 9, 2, 0},
{8, 5, 3, 6}};
Output : Matrix is not in lower triangular form.
PHP
<?php
$N = 4;
function isLowerTriangularMatrix( $mat )
{
global $N ;
for ( $i = 0; $i < $N ; $i ++)
for ( $j = $i + 1; $j < $N ; $j ++)
if ( $mat [ $i ][ $j ] != 0)
return false;
return true;
}
$mat = array ( array ( 1, 0, 0, 0 ),
array ( 1, 4, 0, 0 ),
array ( 4, 6, 2, 0 ),
array ( 0, 4, 7, 6 ));
if (isLowerTriangularMatrix( $mat ))
echo ( "Yes" );
else
echo ( "No" );
?>
|
Output:
Yes
Time Complexity: O(n2), where n represents the number of rows and columns of the given matrix.
Auxiliary Space: O(1), no extra space is required, so it is a constant.
Please refer complete article on Program to check if matrix is lower triangular for more details!
Last Updated :
12 Jun, 2022
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