ex1

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
#  MC886.py
#
#  Copyright 2017 Andre Muricy <ra134949@lazaro.lab.ic.unicamp.br>
#
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#  MA 02110-1301, USA.
#
#
import sklearn

x = [-5.0,  -4.0,   -3.0,   -2.0, -1.0,   0.0,  1.0,  2.0,  3.0,  4.0,  5.0]
y = [-53.9, -28.5,  -20.7,  -3.6, -9.8,   5.0,  4.2,  5.1,  11.4, 27.4, 44.0]

def fun(a, b, c, d, xi):
  res = a*xi*xi*xi + b*xi*xi + c*xi + d
  return res

def gun(a, b, c, d):
  acc = 0
  for i in range(0, len(x)):
    acc = acc + ( y[i] - fun(a, b, c, d, x[i]) ) * ( y[i] - fun(a, b, c, d, x[i]) )
  return acc


print (gun(0, 0, 0, 1))