input: Write a function to filter out all negative numbers from the given matrix using numpy. The function should replace all negative numbers with 0 and return the modified matrix. If the input matrix is empty, return an empty matrix.
  
  import numpy as np
  
  def filter_out_negative(matrix):
    if not matrix:
      return np.array([])
    matrix = np.array(matrix)
    matrix[matrix < 0] = 0
    return matrix
  
  assert np.array_equal(filter_out_negative([[-1, 2, -3], [-4, 5, 6], [-7, 8, 9]]), [[0, 2, 0], [0, 5, 6], [0, 8, 9]])
  assert np.array_equal(filter_out_negative([[1, -2, 3], [-4, 5, -6], [7, 8, 9]]), [[1, 0, 3], [0, 5, 0], [7, 8, 9]])
  assert np.array_equal(filter_out_negative([[0, 0, 0], [0, 0, 0], [0, 0, 0]]), [[0, 0, 0], [0, 0, 0], [0, 0, 0]])
  assert np.array_equal(filter_out_negative([]), np.array([]))
output: 
  def filter_out_negative(matrix):
    if not matrix:
      return np.array([])
    matrix = np.array(matrix)
    matrix[matrix < 0] = 0
    return matrix
  