input: Write a function to filter out all negative numbers from the given matrix. Return the matrix with all negative numbers replaced by 0. If the matrix is empty, return an empty list.
  import numpy as np
  
  def filter_out_negative(matrix):
    if not matrix:
      return []
    # Convert matrix to numpy array
    matrix = np.array(matrix)
    # Find all negative numbers and set them to 0
    matrix[matrix < 0] = 0
    return matrix
  
  assert np.array_equal(filter_out_negative([[-1, 2, -3], [-4, 5, 6], [-7, 8, 9]]), np.array([[0, 2, 0], [0, 5, 6], [0, 8, 9]]))
output: if not matrix:
      return []
  # Convert matrix to numpy array
  matrix = np.array(matrix)
  # Find all negative numbers and set them to 0
  matrix[matrix < 0] = 0
  return matrix