# -*- coding: utf-8 -*-
"""
Created on Thu Aug 30 16:31:10 2018

@author: kaaret
"""

# make Python 2.7 act like Python 3
from __future__ import division, print_function
input = raw_input

# import commonly used libraries
import numpy as np
import matplotlib.pyplot as plt


def row_swap(m, i, j) :
  """
  Swap rows i and j of a matrix m.
  """
  mp = m.copy() # make a copy of the input matrix
  t = mp[i,:].copy() # copy row i of mp, need to copy since next line changes mp
  mp[i,:] = mp[j,:] # copy row j of mp into row i
  mp[j,:] = t # put the copy of the original row i into row j
  return mp

def scalar_mult(m, i, c) :
  """
  Multiply row i of matrix m by c.
  """
  mp = m.copy() # make a copy of the input matrix
  mp[i,:] = c*mp[i,:] # multiply row i by c and put it back into row i
  return mp

def row_add(m, i, j, c) :
  """
  Multiply row i of matrix m by c, add to row j, and replace row j.
  """
  mp = m.copy() # make a copy of the input matrix
  mp[j,:] = c*mp[i,:]+mp[j,:] # multiply row i by c, add to row j, and put sum back into row j
  return mp