Question

A square matrix is diagonally dominant if

Answer 1

if the sum of left diagonal elements is greater than or equal to sum of non diagonal elements in that matrix.

For example:
| 19  1  1|
| 3    5  5|
| 6    2  4|

Here sum of left f=diagonal element is 19+5+4 i.e. 28 which is greater than non diagonal elements, (1+1+5+3+6+2) i.e. 18

Hence this matrix is diagonally dominant