(source : GCP qwiklabs)

 

- Jupyter Notebook 실습 코드 

c_dataset.html
0.27MB

 

- Jupyter Notebook 실습 코드 : 정답  포함

c_dataset_solution.html
0.28MB

 

1. 패키지 import

from google.cloud import bigquery
import tensorflow as tf
import numpy as np
import shutil
print(tf.__version__)

 

2. 입력 Refactor

- Dataset API를 사용하여 데이터가 미니 배치로 모델에 전달 될 때, 필요할 때만 디스크에서 로드됨

CSV_COLUMNS = ['fare_amount', 'pickuplon','pickuplat','dropofflon','dropofflat','passengers', 'key']
DEFAULTS = [[0.0], [-74.0], [40.0], [-74.0], [40.7], [1.0], ['nokey']]

def read_dataset(filename, mode, batch_size = 512):
  def decode_csv(row):
    columns = tf.decode_csv(row, record_defaults = DEFAULTS)
    features = dict(zip(CSV_COLUMNS, columns))
    features.pop('key') # discard, not a real feature
    label = features.pop('fare_amount') # remove label from features and store
    return features, label

  # Create list of file names that match "glob" pattern (i.e. data_file_*.csv)
  filenames_dataset = tf.data.Dataset.list_files(filename, shuffle=False)
  # Read lines from text files
  textlines_dataset = filenames_dataset.flat_map(tf.data.TextLineDataset)
  # Parse text lines as comma-separated values (CSV)
  dataset = textlines_dataset.map(decode_csv)

  # Note:
  # use tf.data.Dataset.flat_map to apply one to many transformations (here: filename -> text lines)
  # use tf.data.Dataset.map      to apply one to one  transformations (here: text line -> feature list)

  if mode == tf.estimator.ModeKeys.TRAIN:
      num_epochs = None # loop indefinitely
      dataset = dataset.shuffle(buffer_size = 10 * batch_size, seed=2)
  else:
      num_epochs = 1 # end-of-input after this

  dataset = dataset.repeat(num_epochs).batch(batch_size)

  return dataset

def get_train_input_fn():
  return read_dataset('./taxi-train.csv', mode = tf.estimator.ModeKeys.TRAIN)

def get_valid_input_fn():
  return read_dataset('./taxi-valid.csv', mode = tf.estimator.ModeKeys.EVAL)

 

 

3. feature 생성 방식 리팩토링

INPUT_COLUMNS = [
    tf.feature_column.numeric_column('pickuplon'),
    tf.feature_column.numeric_column('pickuplat'),
    tf.feature_column.numeric_column('dropofflat'),
    tf.feature_column.numeric_column('dropofflon'),
    tf.feature_column.numeric_column('passengers'),
]

def add_more_features(feats):
  # Nothing to add (yet!)
  return feats

feature_cols = add_more_features(INPUT_COLUMNS)

 

 

4. 모델 생성 및 학습

- num_steps * batch_size 예제 학습

tf.logging.set_verbosity(tf.logging.INFO)
OUTDIR = 'taxi_trained'
shutil.rmtree(OUTDIR, ignore_errors = True) # start fresh each time
model = tf.estimator.LinearRegressor(
      feature_columns = feature_cols, model_dir = OUTDIR)
model.train(input_fn = get_train_input_fn, steps = 200)

 

 

5. 모델 평가

metrics = model.evaluate(input_fn = get_valid_input_fn, steps = None)
print('RMSE on dataset = {}'.format(np.sqrt(metrics['average_loss'])))

 

 

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