Finding the sum of all elements in a matrix is a common operation in mathematical computations and programming. In PHP, this can be achieved using various approaches, including loops and array functions. In this article, we will explore different methods to calculate the sum of all elements in a matrix.

Sum of All Matrix Elements using Nested Loops

This PHP program uses nested loops to find the sum of all elements in a matrix. It iterates through each row and column, adding each element to a running total. The final sum is returned as the result.

Example: Implementation to find the sum of all Matrix elements.

<?php

function sumMatrixElements($matrix) {
    $sum = 0;
    foreach ($matrix as $row) {
        foreach ($row as $element) {
            $sum += $element;
        }
    }
    return $sum;
}

// Driver code
$matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];

$sum = sumMatrixElements($matrix);
echo "Sum of all matrix elements: $sum";

?>

Sum of all matrix elements: 45

Explanation:

• The sumMatrixElements function takes a 2D array (matrix) as input.
• It uses nested foreach loops to iterate through each row and each element in the row.
• The elements are accumulated in the $sum variable, which is returned at the end.

Sum of All Matrix Elements using Array Functions

This PHP program uses array functions to find the sum of all elements in a matrix. It first flattens the matrix into a single-dimensional array using array_map( ) and array_sum( ), then calculates the sum using array_sum( ).

Example: Implementation to find the sum of all Matrix elements.

<?php

function sumMatrixElements($matrix) {
    return array_sum(array_map("array_sum", $matrix));
}

// Driver code
$matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];

$sum = sumMatrixElements($matrix);
echo "Sum of all matrix elements: $sum";

?>

Sum of all matrix elements: 45

Explanation:

• The sumMatrixElements function uses the array_map( ) function to apply array_sum() to each row of the matrix. This results in an array of row sums.
• The array_sum( ) function is then used again to sum the row sums, resulting in the total sum of all matrix elements.

Using array_reduce and array_merge

This PHP program uses array_reduce and array_merge to find the sum of all elements in a matrix. It first flattens the matrix into a single-dimensional array using array_merge, then calculates the sum using array_reduce.

Example: Implementation to find the sum of all Matrix elements

<?php

function sumMatrixElements($matrix) {
    // Flatten the matrix into a single-dimensional array
    $flatArray = call_user_func_array('array_merge', $matrix);
    // Calculate the sum of the flattened array
    $sum = array_reduce($flatArray, function($carry, $item) {
        return $carry + $item;
    }, 0);
    return $sum;
}

// Driver code
$matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];

$sum = sumMatrixElements($matrix);
echo "Sum of all matrix elements: $sum";

?>

Sum of all matrix elements: 45

Approach 4: Using the array_walk_recursive() Function

The array_walk_recursive() function in PHP can be effectively used to compute the sum of all elements in a multidimensional matrix. This function applies a user-defined callback function to each element of an array recursively, allowing you to operate on arrays of arbitrary depth.

Example: Here’s an example that demonstrates how to use array_walk_recursive() to find the sum of all elements in a 2D matrix:

<?php
$matrix = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
];

$sum = 0;  // Initialize sum variable

// Function to sum all elements
array_walk_recursive($matrix, function($value) use (&$sum) {
    $sum += $value;
});

echo "The sum of all matrix elements is: $sum";

?>

The sum of all matrix elements is: 45

Approach 5: Using array_column() and array_sum()

The array_column() function can be used to extract a single column from a multidimensional array. By iterating through the columns of the matrix and summing each column’s values using array_sum(), you can find the total sum of all elements in the matrix.

Example

<?php
function sumMatrixElements($matrix) {
    $totalSum = 0;
    for ($i = 0; $i < count($matrix[0]); $i++) {
        $totalSum += array_sum(array_column($matrix, $i));
    }
    return $totalSum;
}

$matrix = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
];

echo "The sum of all elements in the matrix is: " . sumMatrixElements($matrix);
?>

The sum of all elements in the matrix is: 45