Множественная линейная регрессионная модель с использованием Tensorflow

Question

Я хочу построить модель с несколькими линейными регрессиями с помощью Tensorflow.

Dataset: Portland housing prices

пример Один данные: 2104,3,399900 (Первые две функции, а последняя является цена дома, у нас есть 47 примеров)

код ниже:

import numpy as np 
import tensorflow as tf 
import matplotlib.pyplot as plt 

# model parameters as external flags 
flags = tf.app.flags 
FLAGS = flags.FLAGS 
flags.DEFINE_float('learning_rate', 1.0, 'Initial learning rate.') 
flags.DEFINE_integer('max_steps', 100, 'Number of steps to run trainer.') 
flags.DEFINE_integer('display_step', 100, 'Display logs per step.') 


def run_training(train_X, train_Y): 
    X = tf.placeholder(tf.float32, [m, n]) 
    Y = tf.placeholder(tf.float32, [m, 1]) 

    # weights 
    W = tf.Variable(tf.zeros([n, 1], dtype=np.float32), name="weight") 
    b = tf.Variable(tf.zeros([1], dtype=np.float32), name="bias") 

    # linear model 
    activation = tf.add(tf.matmul(X, W), b) 
    cost = tf.reduce_sum(tf.square(activation - Y))/(2*m) 
    optimizer = tf.train.GradientDescentOptimizer(FLAGS.learning_rate).minimize(cost) 

    with tf.Session() as sess: 
     init = tf.initialize_all_variables() 
     sess.run(init) 

     for step in range(FLAGS.max_steps): 

      sess.run(optimizer, feed_dict={X: np.asarray(train_X), Y: np.asarray(train_Y)}) 

      if step % FLAGS.display_step == 0: 
       print "Step:", "%04d" % (step+1), "Cost=", "{:.2f}".format(sess.run(cost, \ 
        feed_dict={X: np.asarray(train_X), Y: np.asarray(train_Y)})), "W=", sess.run(W), "b=", sess.run(b) 

     print "Optimization Finished!" 
     training_cost = sess.run(cost, feed_dict={X: np.asarray(train_X), Y: np.asarray(train_Y)}) 
     print "Training Cost=", training_cost, "W=", sess.run(W), "b=", sess.run(b), '\n' 

     print "Predict.... (Predict a house with 1650 square feet and 3 bedrooms.)" 
     predict_X = np.array([1650, 3], dtype=np.float32).reshape((1, 2)) 

     # Do not forget to normalize your features when you make this prediction 
     predict_X = predict_X/np.linalg.norm(predict_X) 

     predict_Y = tf.add(tf.matmul(predict_X, W),b) 
     print "House price(Y) =", sess.run(predict_Y) 


def read_data(filename, read_from_file = True): 
    global m, n 

    if read_from_file: 
     with open(filename) as fd: 
      data_list = fd.read().splitlines() 

      m = len(data_list) # number of examples 
      n = 2 # number of features 

      train_X = np.zeros([m, n], dtype=np.float32) 
      train_Y = np.zeros([m, 1], dtype=np.float32) 

      for i in range(m): 
       datas = data_list[i].split(",") 
       for j in range(n): 
        train_X[i][j] = float(datas[j]) 
       train_Y[i][0] = float(datas[-1]) 
    else: 
     m = 47 
     n = 2 

     train_X = np.array([[ 2.10400000e+03, 3.00000000e+00], 
      [ 1.60000000e+03, 3.00000000e+00], 
      [ 2.40000000e+03, 3.00000000e+00], 
      [ 1.41600000e+03, 2.00000000e+00], 
      [ 3.00000000e+03, 4.00000000e+00], 
      [ 1.98500000e+03, 4.00000000e+00], 
      [ 1.53400000e+03, 3.00000000e+00], 
      [ 1.42700000e+03, 3.00000000e+00], 
      [ 1.38000000e+03, 3.00000000e+00], 
      [ 1.49400000e+03, 3.00000000e+00], 
      [ 1.94000000e+03, 4.00000000e+00], 
      [ 2.00000000e+03, 3.00000000e+00], 
      [ 1.89000000e+03, 3.00000000e+00], 
      [ 4.47800000e+03, 5.00000000e+00], 
      [ 1.26800000e+03, 3.00000000e+00], 
      [ 2.30000000e+03, 4.00000000e+00], 
      [ 1.32000000e+03, 2.00000000e+00], 
      [ 1.23600000e+03, 3.00000000e+00], 
      [ 2.60900000e+03, 4.00000000e+00], 
      [ 3.03100000e+03, 4.00000000e+00], 
      [ 1.76700000e+03, 3.00000000e+00], 
      [ 1.88800000e+03, 2.00000000e+00], 
      [ 1.60400000e+03, 3.00000000e+00], 
      [ 1.96200000e+03, 4.00000000e+00], 
      [ 3.89000000e+03, 3.00000000e+00], 
      [ 1.10000000e+03, 3.00000000e+00], 
      [ 1.45800000e+03, 3.00000000e+00], 
      [ 2.52600000e+03, 3.00000000e+00], 
      [ 2.20000000e+03, 3.00000000e+00], 
      [ 2.63700000e+03, 3.00000000e+00], 
      [ 1.83900000e+03, 2.00000000e+00], 
      [ 1.00000000e+03, 1.00000000e+00], 
      [ 2.04000000e+03, 4.00000000e+00], 
      [ 3.13700000e+03, 3.00000000e+00], 
      [ 1.81100000e+03, 4.00000000e+00], 
      [ 1.43700000e+03, 3.00000000e+00], 
      [ 1.23900000e+03, 3.00000000e+00], 
      [ 2.13200000e+03, 4.00000000e+00], 
      [ 4.21500000e+03, 4.00000000e+00], 
      [ 2.16200000e+03, 4.00000000e+00], 
      [ 1.66400000e+03, 2.00000000e+00], 
      [ 2.23800000e+03, 3.00000000e+00], 
      [ 2.56700000e+03, 4.00000000e+00], 
      [ 1.20000000e+03, 3.00000000e+00], 
      [ 8.52000000e+02, 2.00000000e+00], 
      [ 1.85200000e+03, 4.00000000e+00], 
      [ 1.20300000e+03, 3.00000000e+00]] 
     ).astype('float32') 

     train_Y = np.array([[ 399900.], 
      [ 329900.], 
      [ 369000.], 
      [ 232000.], 
      [ 539900.], 
      [ 299900.], 
      [ 314900.], 
      [ 198999.], 
      [ 212000.], 
      [ 242500.], 
      [ 239999.], 
      [ 347000.], 
      [ 329999.], 
      [ 699900.], 
      [ 259900.], 
      [ 449900.], 
      [ 299900.], 
      [ 199900.], 
      [ 499998.], 
      [ 599000.], 
      [ 252900.], 
      [ 255000.], 
      [ 242900.], 
      [ 259900.], 
      [ 573900.], 
      [ 249900.], 
      [ 464500.], 
      [ 469000.], 
      [ 475000.], 
      [ 299900.], 
      [ 349900.], 
      [ 169900.], 
      [ 314900.], 
      [ 579900.], 
      [ 285900.], 
      [ 249900.], 
      [ 229900.], 
      [ 345000.], 
      [ 549000.], 
      [ 287000.], 
      [ 368500.], 
      [ 329900.], 
      [ 314000.], 
      [ 299000.], 
      [ 179900.], 
      [ 299900.], 
      [ 239500.]] 
     ).astype('float32') 

    return train_X, train_Y 


def feature_normalize(train_X): 

    train_X_tmp = train_X.transpose() 

    for N in range(2): 
     train_X_tmp[N] = train_X_tmp[N]/np.linalg.norm(train_X_tmp[N]) 

    train_X = train_X_tmp.transpose() 

    return train_X 
import sys 

def main(argv): 
    if not argv: 
     print "Enter data filename." 
     sys.exit() 

    filename = argv[1] 

    train_X, train_Y = read_data(filename, False) 
    train_X = feature_normalize(train_X) 
    run_training(train_X, train_Y) 

if __name__ == '__main__': 
    tf.app.run() 

Результаты я получил:

со скоростью обучения 1,0 и 100 итераций, модель Fina LLY предсказывает дом с 1650 квадратных футов и 3 спальни получить цену $ 752903, с:

Стоимость обучения = 4.94429e + 09

W = [[505305,375] [177712,625]]

б = [ 247275.515625]

Там должны быть какие-то ошибки в своем коде как график функции затрат для различных скоростей обучения просто не то же самое с solution

Я должен получили следующие результаты в виде предложенного решения:

theta_0: 340.413

theta_1: 110.631

theta_2: -6.649

Прогнозируемая цена дома должна быть $ 293081.

Неправильное использование моего тензорного потока?

Answer 1

Нормализация функции должна выполняться путем вычитания среднего значения и деления на диапазон (или стандартное отклонение).

def feature_normalize(train_X): 

    global mean, std 
    mean = np.mean(train_X, axis=0) 
    std = np.std(train_X, axis=0) 

    return (train_X - mean)/std 

Не забудьте нормализовать свои функции, когда вы делаете это предсказание.

predict_X = (predict_X - mean)/std 

Answer 2

Вы должны попробовать:

for (x, y) in zip(train_X, train_Y): 
    sess.run(optimizer, feed_dict={X: x, Y: y}) 

вместо:

sess.run(optimizer, feed_dict={X: np.asarray(train_X), Y: np.asarray(train_Y)}) 

Причина, вы код работает только с одним элементом в списке train_X и train_Y.

Надеюсь, это поможет вам,