lower triangular matrix in javascript

To create a lower triangular matrix in JavaScript, we can use nested loops to set the values below the main diagonal to zero. Here's an example function:

index.tsx
function lowerTriangular(matrix) {
  var rows = matrix.length;

  // Loop through each row
  for (var i = 0; i < rows; i++) {
    // Loop through each column
    for (var j = i + 1; j < rows; j++) {
      // Set values below the diagonal to zero
      matrix[j][i] = 0;
    }
  }

  return matrix;
}
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This function takes a two-dimensional array matrix as input, and modifies it in place to create the lower triangular matrix.

We first get the number of rows in the matrix using the length property. We then use two nested loops to iterate over each element below the main diagonal (elements where the row index is greater than the column index). For each of these elements, we set its value to 0.

Finally, we return the modified matrix.

Here's an example usage of the function:

index.tsx
var matrix = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
];

var lower = lowerTriangular(matrix);

console.log(lower);
// Output: [[1, 0, 0], [4, 5, 0], [7, 8, 9]]
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This will output the lower triangular matrix for the input matrix.