w3resource

JavaScript: Check whether a matrix is a diagonal matrix or not

JavaScript Basic: Exercise-115 with Solution

Write a JavaScript program to check whether a matrix is a diagonal matrix or not. In linear algebra, a diagonal matrix is a matrix in which the entries outside the main diagonal are all zero (the diagonal from the upper left to the lower right).

Example:
[1, 0, 0], [0, 2, 0], [0, 0, 3] ]) = true
[1, 0, 0], [0, 2, 3], [0, 0, 3] ]) = false

Pictorial Presentation:

JavaScript: Check whether a matrix is a diagonal matrix or not.

Sample Solution:

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title> Check whether a matrix is a diagonal matrix or not</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function is_diagonal_matrix(user_matrix) {
    for (var i = 0; i < user_matrix.length; i++) {
        for (var j = 0; j < user_matrix.length; j++) {
            if (i !== j && user_matrix[i][j] !== 0) 
              return false;
        }
    }
    return true;
}


console.log(is_diagonal_matrix([[1, 0, 0], [0, 2, 0], [0, 0, 3] ]));
console.log(is_diagonal_matrix([[1, 0, 0], [0, 2, 3], [0, 0, 3] ]));

Sample Output:

true
false

Flowchart:

Flowchart: JavaScript - Check whether a matrix is a diagonal matrix or not

ES6 Version:

function is_diagonal_matrix(user_matrix) {
    for (let i = 0; i < user_matrix.length; i++) {
        for (let j = 0; j < user_matrix.length; j++) {
            if (i !== j && user_matrix[i][j] !== 0) 
              return false;
        }
    }
    return true;
}


console.log(is_diagonal_matrix([[1, 0, 0], [0, 2, 0], [0, 0, 3] ]));
console.log(is_diagonal_matrix([[1, 0, 0], [0, 2, 3], [0, 0, 3] ]));

Live Demo:

See the Pen javascript-basic-exercise-115 by w3resource (@w3resource) on CodePen.


Contribute your code and comments through Disqus.

Previous: Write a JavaScript program to check whether a given string represents a correct sentence or not.
Next: Write a JavaScript program to find all the possible options to replace the hash in a string (Consists of digits and one hash (#)) with a digit to produce an integer divisible by 3.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Share this Tutorial / Exercise on : Facebook and Twitter

JavaScript: Tips of the Day

Returns the sum of the powers of all the numbers from start to end (both inclusive)

Example:

const sumPower = (end, power = 2, start = 1) =>
  Array(end + 1 - start)
    .fill(0)
    .map((x, i) => (i + start) ** power)
    .reduce((a, b) => a + b, 0);
console.log(sumPower(10)); // 385
console.log(sumPower(10, 3)); // 3025
console.log(sumPower(10, 3, 5)); // 2925 

Output:

385
3025
2925