In [2]:
sc = SparkContext.getOrCreate()
In [3]:
# carregar base de dados
from test_helper import Test
import os.path
baseDir = os.path.join('Data')
inputPath = os.path.join('millionsong.txt')
fileName = os.path.join(baseDir, inputPath)
numPartitions = 2
rawData = sc.textFile(fileName, numPartitions)
In [4]:
# EXERCICIO
numPoints = rawData.count()
print numPoints
samplePoints = rawData.take(5)
print samplePoints
In [5]:
# TEST Load and check the data (1a)
Test.assertEquals(numPoints, 6724, 'incorrect value for numPoints')
Test.assertEquals(len(samplePoints), 5, 'incorrect length for samplePoints')
LabeledPoint parsePoint que recebe como entrada uma amostra de dados, transforma os dados usandoo comando unicode.split, e retorna um LabeledPoint.samplePoints da célula anterior e imprima os atributos e rótulo utilizando os atributos LabeledPoint.features e LabeledPoint.label. Finalmente, calcule o número de atributos nessa base de dados.
In [6]:
from pyspark.mllib.regression import LabeledPoint
import numpy as np
# Here is a sample raw data point:
# '2001.0,0.884,0.610,0.600,0.474,0.247,0.357,0.344,0.33,0.600,0.425,0.60,0.419'
# In this raw data point, 2001.0 is the label, and the remaining values are features
In [7]:
# EXERCICIO
def parsePoint(line):
"""Converts a comma separated unicode string into a `LabeledPoint`.
Args:
line (unicode): Comma separated unicode string where the first element is the label and the
remaining elements are features.
Returns:
LabeledPoint: The line is converted into a `LabeledPoint`, which consists of a label and
features.
"""
Point = line.split(",")
return LabeledPoint(Point[0], Point[1:])
parsedSamplePoints = map(parsePoint,samplePoints)
firstPointFeatures = parsedSamplePoints[0].features
firstPointLabel = parsedSamplePoints[0].label
print firstPointFeatures, firstPointLabel
d = len(firstPointFeatures)
print d
In [8]:
# TEST Using LabeledPoint (1b)
Test.assertTrue(isinstance(firstPointLabel, float), 'label must be a float')
expectedX0 = [0.8841,0.6105,0.6005,0.4747,0.2472,0.3573,0.3441,0.3396,0.6009,0.4257,0.6049,0.4192]
Test.assertTrue(np.allclose(expectedX0, firstPointFeatures, 1e-4, 1e-4),
'incorrect features for firstPointFeatures')
Test.assertTrue(np.allclose(2001.0, firstPointLabel), 'incorrect label for firstPointLabel')
Test.assertTrue(d == 12, 'incorrect number of features')
In [9]:
#insert a graphic inline
%matplotlib inline
import matplotlib.pyplot as plt
import matplotlib.cm as cm
sampleMorePoints = rawData.take(50)
parsedSampleMorePoints = map(parsePoint, sampleMorePoints)
dataValues = map(lambda lp: lp.features.toArray(), parsedSampleMorePoints)
#print dataValues
def preparePlot(xticks, yticks, figsize=(10.5, 6), hideLabels=False, gridColor='#999999',
gridWidth=1.0):
"""Template for generating the plot layout."""
plt.close()
fig, ax = plt.subplots(figsize=figsize, facecolor='white', edgecolor='white')
ax.axes.tick_params(labelcolor='#999999', labelsize='10')
for axis, ticks in [(ax.get_xaxis(), xticks), (ax.get_yaxis(), yticks)]:
axis.set_ticks_position('none')
axis.set_ticks(ticks)
axis.label.set_color('#999999')
if hideLabels: axis.set_ticklabels([])
plt.grid(color=gridColor, linewidth=gridWidth, linestyle='-')
map(lambda position: ax.spines[position].set_visible(False), ['bottom', 'top', 'left', 'right'])
return fig, ax
# generate layout and plot
fig, ax = preparePlot(np.arange(.5, 11, 1), np.arange(.5, 49, 1), figsize=(8,7), hideLabels=True,
gridColor='#eeeeee', gridWidth=1.1)
image = plt.imshow(dataValues,interpolation='nearest', aspect='auto', cmap=cm.Greys)
for x, y, s in zip(np.arange(-.125, 12, 1), np.repeat(-.75, 12), [str(x) for x in range(12)]):
plt.text(x, y, s, color='#999999', size='10')
plt.text(4.7, -3, 'Feature', color='#999999', size='11'), ax.set_ylabel('Observation')
pass
In [10]:
# EXERCICIO
parsedDataInit = rawData.map(lambda x: parsePoint(x))
onlyLabels = parsedDataInit.map(lambda x: x.label)
minYear = onlyLabels.min()
maxYear = onlyLabels.max()
print maxYear, minYear
In [11]:
# TEST Find the range (1c)
Test.assertEquals(len(parsedDataInit.take(1)[0].features), 12,
'unexpected number of features in sample point')
sumFeatTwo = parsedDataInit.map(lambda lp: lp.features[2]).sum()
Test.assertTrue(np.allclose(sumFeatTwo, 3158.96224351), 'parsedDataInit has unexpected values')
yearRange = maxYear - minYear
Test.assertTrue(yearRange == 89, 'incorrect range for minYear to maxYear')
In [12]:
# Debug
parsedDataInit.take(1)
Out[12]:
In [13]:
# EXERCICIO
parsedData = parsedDataInit.map(lambda x: LabeledPoint(x.label - minYear, x.features))
# Should be a LabeledPoint
print type(parsedData.take(1)[0])
# View the first point
print '\n{0}'.format(parsedData.take(1))
In [14]:
# TEST Shift labels (1d)
oldSampleFeatures = parsedDataInit.take(1)[0].features
newSampleFeatures = parsedData.take(1)[0].features
Test.assertTrue(np.allclose(oldSampleFeatures, newSampleFeatures),
'new features do not match old features')
sumFeatTwo = parsedData.map(lambda lp: lp.features[2]).sum()
Test.assertTrue(np.allclose(sumFeatTwo, 3158.96224351), 'parsedData has unexpected values')
minYearNew = parsedData.map(lambda lp: lp.label).min()
maxYearNew = parsedData.map(lambda lp: lp.label).max()
Test.assertTrue(minYearNew == 0, 'incorrect min year in shifted data')
Test.assertTrue(maxYearNew == 89, 'incorrect max year in shifted data')
cache() faça o pré-armazenamento da base processada.
In [15]:
# EXERCICIO
weights = [.8, .1, .1]
seed = 42
parsedTrainData, parsedValData, parsedTestData = parsedData.randomSplit(weights, seed)
parsedTrainData.cache()
parsedValData.cache()
parsedTestData.cache()
nTrain = parsedTrainData.count()
nVal = parsedValData.count()
nTest = parsedTestData.count()
print nTrain, nVal, nTest, nTrain + nVal + nTest
print parsedData.count()
In [16]:
# TEST Training, validation, and test sets (1e)
Test.assertEquals(parsedTrainData.getNumPartitions(), numPartitions,
'parsedTrainData has wrong number of partitions')
Test.assertEquals(parsedValData.getNumPartitions(), numPartitions,
'parsedValData has wrong number of partitions')
Test.assertEquals(parsedTestData.getNumPartitions(), numPartitions,
'parsedTestData has wrong number of partitions')
Test.assertEquals(len(parsedTrainData.take(1)[0].features), 12,
'parsedTrainData has wrong number of features')
sumFeatTwo = (parsedTrainData
.map(lambda lp: lp.features[2])
.sum())
sumFeatThree = (parsedValData
.map(lambda lp: lp.features[3])
.reduce(lambda x, y: x + y))
sumFeatFour = (parsedTestData
.map(lambda lp: lp.features[4])
.reduce(lambda x, y: x + y))
Test.assertTrue(np.allclose([sumFeatTwo, sumFeatThree, sumFeatFour],
2526.87757656, 297.340394298, 184.235876654),
'parsed Train, Val, Test data has unexpected values')
Test.assertTrue(nTrain + nVal + nTest == 6724, 'unexpected Train, Val, Test data set size')
Test.assertEquals(nTrain, 5371, 'unexpected value for nTrain')
Test.assertEquals(nVal, 682, 'unexpected value for nVal')
Test.assertEquals(nTest, 671, 'unexpected value for nTest')
In [17]:
# EXERCICIO
averageTrainYear = (parsedTrainData
.map(lambda x: x.label)
.mean()
)
print averageTrainYear
In [18]:
# TEST Average label (2a)
Test.assertTrue(np.allclose(averageTrainYear, 53.9316700801),
'incorrect value for averageTrainYear')
In [19]:
# EXERCICIO
def squaredError(label, prediction):
"""Calculates the the squared error for a single prediction.
Args:
label (float): The correct value for this observation.
prediction (float): The predicted value for this observation.
Returns:
float: The difference between the `label` and `prediction` squared.
"""
return np.square(label - prediction)
def calcRMSE(labelsAndPreds):
"""Calculates the root mean squared error for an `RDD` of (label, prediction) tuples.
Args:
labelsAndPred (RDD of (float, float)): An `RDD` consisting of (label, prediction) tuples.
Returns:
float: The square root of the mean of the squared errors.
"""
return np.sqrt(labelsAndPreds.map(lambda (x,y): squaredError(x,y)).mean())
labelsAndPreds = sc.parallelize([(3., 1.), (1., 2.), (2., 2.)])
# RMSE = sqrt[((3-1)^2 + (1-2)^2 + (2-2)^2) / 3] = 1.291
exampleRMSE = calcRMSE(labelsAndPreds)
print exampleRMSE
In [20]:
# TEST Root mean squared error (2b)
Test.assertTrue(np.allclose(squaredError(3, 1), 4.), 'incorrect definition of squaredError')
Test.assertTrue(np.allclose(exampleRMSE, 1.29099444874), 'incorrect value for exampleRMSE')
In [21]:
#Debug
parsedTrainData.take(1)
Out[21]:
In [22]:
# EXERCICIO -> (rótulo, predição)
labelsAndPredsTrain = parsedTrainData.map(lambda x:(x.label, averageTrainYear))
rmseTrainBase = calcRMSE(labelsAndPredsTrain)
labelsAndPredsVal = parsedValData.map(lambda x:(x.label, averageTrainYear))
rmseValBase = calcRMSE(labelsAndPredsVal)
labelsAndPredsTest = parsedTestData.map(lambda x:(x.label, averageTrainYear))
rmseTestBase = calcRMSE(labelsAndPredsTest)
print 'Baseline Train RMSE = {0:.3f}'.format(rmseTrainBase)
print 'Baseline Validation RMSE = {0:.3f}'.format(rmseValBase)
print 'Baseline Test RMSE = {0:.3f}'.format(rmseTestBase)
In [23]:
# TEST Training, validation and test RMSE (2c)
Test.assertTrue(np.allclose([rmseTrainBase, rmseValBase, rmseTestBase],
[21.305869, 21.586452, 22.136957]), 'incorrect RMSE value')
In [24]:
from matplotlib.colors import ListedColormap, Normalize
from matplotlib.cm import get_cmap
cmap = get_cmap('YlOrRd')
norm = Normalize()
actual = np.asarray(parsedValData
.map(lambda lp: lp.label)
.collect())
error = np.asarray(parsedValData
.map(lambda lp: (lp.label, lp.label))
.map(lambda (l, p): squaredError(l, p))
.collect())
clrs = cmap(np.asarray(norm(error)))[:,0:3]
fig, ax = preparePlot(np.arange(0, 100, 20), np.arange(0, 100, 20))
plt.scatter(actual, actual, s=14**2, c=clrs, edgecolors='#888888', alpha=0.75, linewidths=0.5)
ax.set_xlabel('Predicted'), ax.set_ylabel('Actual')
pass
In [25]:
predictions = np.asarray(parsedValData
.map(lambda lp: averageTrainYear)
.collect())
error = np.asarray(parsedValData
.map(lambda lp: (lp.label, averageTrainYear))
.map(lambda (l, p): squaredError(l, p))
.collect())
norm = Normalize()
clrs = cmap(np.asarray(norm(error)))[:,0:3]
fig, ax = preparePlot(np.arange(53.0, 55.0, 0.5), np.arange(0, 100, 20))
ax.set_xlim(53, 55)
plt.scatter(predictions, actual, s=14**2, c=clrs, edgecolors='#888888', alpha=0.75, linewidths=0.3)
ax.set_xlabel('Predicted'), ax.set_ylabel('Actual')
Out[25]:
DenseVector dot para representar a lista de atributos (ele tem funcionalidade parecida com o np.array()).
In [26]:
from pyspark.mllib.linalg import DenseVector
In [27]:
# EXERCICIO
def gradientSummand(weights, lp):
"""Calculates the gradient summand for a given weight and `LabeledPoint`.
Note:
`DenseVector` behaves similarly to a `numpy.ndarray` and they can be used interchangably
within this function. For example, they both implement the `dot` method.
Args:
weights (DenseVector): An array of model weights (betas).
lp (LabeledPoint): The `LabeledPoint` for a single observation.
Returns:
DenseVector: An array of values the same length as `weights`. The gradient summand.
"""
return (weights.dot(lp.features) - lp.label) * lp.features
exampleW = DenseVector([1, 1, 1])
exampleLP = LabeledPoint(2.0, [3, 1, 4])
summandOne = gradientSummand(exampleW, exampleLP)
print summandOne
exampleW = DenseVector([.24, 1.2, -1.4])
exampleLP = LabeledPoint(3.0, [-1.4, 4.2, 2.1])
summandTwo = gradientSummand(exampleW, exampleLP)
print summandTwo
In [28]:
# TEST Gradient summand (3a)
Test.assertTrue(np.allclose(summandOne, [18., 6., 24.]), 'incorrect value for summandOne')
Test.assertTrue(np.allclose(summandTwo, [1.7304,-5.1912,-2.5956]), 'incorrect value for summandTwo')
In [29]:
# EXERCICIO
def getLabeledPrediction(weights, observation):
"""Calculates predictions and returns a (label, prediction) tuple.
Note:
The labels should remain unchanged as we'll use this information to calculate prediction
error later.
Args:
weights (np.ndarray): An array with one weight for each features in `trainData`.
observation (LabeledPoint): A `LabeledPoint` that contain the correct label and the
features for the data point.
Returns:
tuple: A (label, prediction) tuple.
"""
return ( observation.label, weights.dot(observation.features) )
weights = np.array([1.0, 1.5])
predictionExample = sc.parallelize([LabeledPoint(2, np.array([1.0, .5])),
LabeledPoint(1.5, np.array([.5, .5]))])
labelsAndPredsExample = predictionExample.map(lambda lp: getLabeledPrediction(weights, lp))
print labelsAndPredsExample.collect()
In [30]:
# TEST Use weights to make predictions (3b)
Test.assertEquals(labelsAndPredsExample.collect(), [(2.0, 1.75), (1.5, 1.25)],
'incorrect definition for getLabeledPredictions')
In [31]:
# EXERCICIO
def linregGradientDescent(trainData, numIters):
"""Calculates the weights and error for a linear regression model trained with gradient descent.
Note:
`DenseVector` behaves similarly to a `numpy.ndarray` and they can be used interchangably
within this function. For example, they both implement the `dot` method.
Args:
trainData (RDD of LabeledPoint): The labeled data for use in training the model.
numIters (int): The number of iterations of gradient descent to perform.
Returns:
(np.ndarray, np.ndarray): A tuple of (weights, training errors). Weights will be the
final weights (one weight per feature) for the model, and training errors will contain
an error (RMSE) for each iteration of the algorithm.
"""
# The length of the training data
n = trainData.count()
# The number of features in the training data
d = len(trainData.take(1)[0].features)
w = np.zeros(d)
alpha = 1.0
# We will compute and store the training error after each iteration
errorTrain = np.zeros(numIters)
for i in range(numIters):
# Use getLabeledPrediction from (3b) with trainData to obtain an RDD of (label, prediction)
# tuples. Note that the weights all equal 0 for the first iteration, so the predictions will
# have large errors to start.
labelsAndPredsTrain = trainData.map(lambda x: getLabeledPrediction(w, x))
errorTrain[i] = calcRMSE(labelsAndPredsTrain)
# Calculate the `gradient`. Make use of the `gradientSummand` function you wrote in (3a).
# Note that `gradient` sould be a `DenseVector` of length `d`.
gradient = trainData.map(lambda x: gradientSummand(w, x)).sum()
# Update the weights
alpha_i = alpha / (n * np.sqrt(i+1))
w -= alpha_i*gradient
return w, errorTrain
# create a toy dataset with n = 10, d = 3, and then run 5 iterations of gradient descent
# note: the resulting model will not be useful; the goal here is to verify that
# linregGradientDescent is working properly
exampleN = 10
exampleD = 3
exampleData = (sc
.parallelize(parsedTrainData.take(exampleN))
.map(lambda lp: LabeledPoint(lp.label, lp.features[0:exampleD])))
print exampleData.take(2)
exampleNumIters = 5
exampleWeights, exampleErrorTrain = linregGradientDescent(exampleData, exampleNumIters)
print exampleWeights
In [32]:
# TEST Gradient descent (3c)
expectedOutput = [48.88110449, 36.01144093, 30.25350092]
Test.assertTrue(np.allclose(exampleWeights, expectedOutput), 'value of exampleWeights is incorrect')
expectedError = [79.72013547, 30.27835699, 9.27842641, 9.20967856, 9.19446483]
Test.assertTrue(np.allclose(exampleErrorTrain, expectedError),
'value of exampleErrorTrain is incorrect')
In [33]:
# EXERCICIO
numIters = 50
weightsLR0, errorTrainLR0 = linregGradientDescent(parsedTrainData, numIters)
labelsAndPreds = parsedValData.map(lambda x: getLabeledPrediction(weightsLR0, x))
rmseValLR0 = calcRMSE(labelsAndPreds)
print 'Validation RMSE:\n\tBaseline = {0:.3f}\n\tLR0 = {1:.3f}'.format(rmseValBase,
rmseValLR0)
In [34]:
# TEST Train the model (3d)
expectedOutput = [22.64535883, 20.064699, -0.05341901, 8.2931319, 5.79155768, -4.51008084,
15.23075467, 3.8465554, 9.91992022, 5.97465933, 11.36849033, 3.86452361]
Test.assertTrue(np.allclose(weightsLR0, expectedOutput), 'incorrect value for weightsLR0')
In [35]:
norm = Normalize()
clrs = cmap(np.asarray(norm(np.log(errorTrainLR0))))[:,0:3]
fig, ax = preparePlot(np.arange(0, 60, 10), np.arange(2, 6, 1))
ax.set_ylim(2, 6)
plt.scatter(range(0, numIters), np.log(errorTrainLR0), s=14**2, c=clrs, edgecolors='#888888', alpha=0.75)
ax.set_xlabel('Iteration'), ax.set_ylabel(r'$\log_e(errorTrainLR0)$')
pass
In [36]:
norm = Normalize()
clrs = cmap(np.asarray(norm(errorTrainLR0[6:])))[:,0:3]
fig, ax = preparePlot(np.arange(0, 60, 10), np.arange(17, 22, 1))
ax.set_ylim(17.8, 21.2)
plt.scatter(range(0, numIters-6), errorTrainLR0[6:], s=14**2, c=clrs, edgecolors='#888888', alpha=0.75)
ax.set_xticklabels(map(str, range(6, 66, 10)))
ax.set_xlabel('Iteration'), ax.set_ylabel(r'Training Error')
pass
LinearRegressionWithSGD
In [37]:
from pyspark.mllib.regression import LinearRegressionWithSGD
# Values to use when training the linear regression model
numIters = 500 # iterations
alpha = 1.0 # step
miniBatchFrac = 1.0 # miniBatchFraction
reg = 1e-1 # regParam
regType = 'l2' # regType
useIntercept = True # intercept
In [45]:
# EXERCICIO
firstModel = LinearRegressionWithSGD.train(parsedTrainData, iterations = numIters, step = alpha, miniBatchFraction = 1.0,
regParam=reg,regType=regType, intercept=useIntercept)
# weightsLR1 stores the model weights; interceptLR1 stores the model intercept
weightsLR1 = firstModel.weights
interceptLR1 = firstModel.intercept
print weightsLR1, interceptLR1
In [46]:
# TEST LinearRegressionWithSGD (4a)
expectedIntercept = 13.3335907631
expectedWeights = [16.682292427, 14.7439059559, -0.0935105608897, 6.22080088829, 4.01454261926, -3.30214858535,
11.0403027232, 2.67190962854, 7.18925791279, 4.46093254586, 8.14950409475, 2.75135810882]
Test.assertTrue(np.allclose(interceptLR1, expectedIntercept), 'incorrect value for interceptLR1')
Test.assertTrue(np.allclose(weightsLR1, expectedWeights), 'incorrect value for weightsLR1')
features de um LabeledPoint comp parâmetro.
In [47]:
# EXERCICIO
samplePoint = parsedTrainData.take(1)[0]
samplePrediction = firstModel.predict(samplePoint.features)
print samplePrediction
In [48]:
# TEST Predict (4b)
Test.assertTrue(np.allclose(samplePrediction, 56.8013380112),
'incorrect value for samplePrediction')
In [49]:
# EXERCICIO
labelsAndPreds = parsedValData.map(lambda x: (x.label, firstModel.predict(x.features)))
rmseValLR1 = calcRMSE(labelsAndPreds)
print ('Validation RMSE:\n\tBaseline = {0:.3f}\n\tLR0 = {1:.3f}' +
'\n\tLR1 = {2:.3f}').format(rmseValBase, rmseValLR0, rmseValLR1)
In [50]:
# TEST Evaluate RMSE (4c)
Test.assertTrue(np.allclose(rmseValLR1, 19.691247), 'incorrect value for rmseValLR1')
In [52]:
# EXERCICIO
bestRMSE = rmseValLR1
bestRegParam = reg
bestModel = firstModel
numIters = 500
alpha = 1.0
miniBatchFrac = 1.0
for reg in [1e-10, 1e-5, 1]:
model = LinearRegressionWithSGD.train(parsedTrainData, numIters, alpha,
miniBatchFrac, regParam=reg,
regType='l2', intercept=True)
labelsAndPreds = parsedValData.map(lambda x: (x.label, model.predict(x.features)))
rmseValGrid = calcRMSE(labelsAndPreds)
print rmseValGrid
if rmseValGrid < bestRMSE:
bestRMSE = rmseValGrid
bestRegParam = reg
bestModel = model
rmseValLRGrid = bestRMSE
print ('Validation RMSE:\n\tBaseline = {0:.3f}\n\tLR0 = {1:.3f}\n\tLR1 = {2:.3f}\n' +
'\tLRGrid = {3:.3f}').format(rmseValBase, rmseValLR0, rmseValLR1, rmseValLRGrid)
In [53]:
# TEST Grid search (4d)
Test.assertTrue(np.allclose(17.017170, rmseValLRGrid), 'incorrect value for rmseValLRGrid')
In [60]:
predictions = np.asarray(parsedValData
.map(lambda lp: bestModel.predict(lp.features))
.collect())
actual = np.asarray(parsedValData
.map(lambda lp: lp.label)
.collect())
error = np.asarray(parsedValData
.map(lambda lp: (lp.label, bestModel.predict(lp.features)))
.map(lambda (l, p): squaredError(l, p))
.collect())
norm = Normalize()
clrs = cmap(np.asarray(norm(error)))[:,0:3]
fig, ax = preparePlot(np.arange(0, 120, 20), np.arange(0, 120, 20))
ax.set_xlim(15, 82), ax.set_ylim(-5, 105)
plt.scatter(predictions, actual, s=14**2, c=clrs, edgecolors='#888888', alpha=0.75, linewidths=.5)
ax.set_xlabel('Predicted'), ax.set_ylabel(r'Actual')
pass
1e-5 e 10 para alpha e os valores 500 e 5 para número de iterações. Avalie todos os modelos no conjunto de valdação. Reparem que com um valor baixo de alpha, o algoritmo necessita de muito mais iterações para convergir ao ótimo, enquanto um valor muito alto para alpha, pode fazer com que o algoritmo não encontre uma solução.
In [63]:
# EXERCICIO
reg = bestRegParam
modelRMSEs = []
for alpha in [1e-5, 10]:
for numIters in [500, 5]:
model = LinearRegressionWithSGD.train(parsedTrainData, numIters, alpha,
miniBatchFrac, regParam=reg,
regType='l2', intercept=True)
labelsAndPreds = parsedValData.map(lambda lp: (lp.label, model.predict(lp.features)))
rmseVal = calcRMSE(labelsAndPreds)
print 'alpha = {0:.0e}, numIters = {1}, RMSE = {2:.3f}'.format(alpha, numIters, rmseVal)
modelRMSEs.append(rmseVal)
In [64]:
# TEST Vary alpha and the number of iterations (4e)
expectedResults = sorted([56.969705, 56.892949, 355124752.221221])
Test.assertTrue(np.allclose(sorted(modelRMSEs)[:3], expectedResults), 'incorrect value for modelRMSEs')
twoWayInteractions que recebe um LabeledPoint e gera um novo LabeledPoint que contém os atributos antigos e as interações par a par entre eles. Note que um objeto com 3 atributos terá nove interações ( $ \scriptsize 3^2 $ ) par a par.
In [ ]:
# EXERCICIO
import itertools
def twoWayInteractions(lp):
"""Creates a new `LabeledPoint` that includes two-way interactions.
Note:
For features [x, y] the two-way interactions would be [x^2, x*y, y*x, y^2] and these
would be appended to the original [x, y] feature list.
Args:
lp (LabeledPoint): The label and features for this observation.
Returns:
LabeledPoint: The new `LabeledPoint` should have the same label as `lp`. Its features
should include the features from `lp` followed by the two-way interaction features.
"""
newfeats = <COMPLETAR>
return LabeledPoint(lp.label, <COMPLETAR>)
#return lp
print twoWayInteractions(LabeledPoint(0.0, [2, 3]))
# Transform the existing train, validation, and test sets to include two-way interactions.
trainDataInteract = parsedTrainData.map(twoWayInteractions)
valDataInteract = parsedValData.map(twoWayInteractions)
testDataInteract = parsedTestData.map(twoWayInteractions)
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# TEST Add two-way interactions (5a)
twoWayExample = twoWayInteractions(LabeledPoint(0.0, [2, 3]))
Test.assertTrue(np.allclose(sorted(twoWayExample.features),
sorted([2.0, 3.0, 4.0, 6.0, 6.0, 9.0])),
'incorrect features generatedBy twoWayInteractions')
twoWayPoint = twoWayInteractions(LabeledPoint(1.0, [1, 2, 3]))
Test.assertTrue(np.allclose(sorted(twoWayPoint.features),
sorted([1.0,2.0,3.0,1.0,2.0,3.0,2.0,4.0,6.0,3.0,6.0,9.0])),
'incorrect features generated by twoWayInteractions')
Test.assertEquals(twoWayPoint.label, 1.0, 'incorrect label generated by twoWayInteractions')
Test.assertTrue(np.allclose(sum(trainDataInteract.take(1)[0].features), 40.821870576035529),
'incorrect features in trainDataInteract')
Test.assertTrue(np.allclose(sum(valDataInteract.take(1)[0].features), 45.457719932695696),
'incorrect features in valDataInteract')
Test.assertTrue(np.allclose(sum(testDataInteract.take(1)[0].features), 35.109111632783168),
'incorrect features in testDataInteract')
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# EXERCICIO
numIters = 500
alpha = 1.0
miniBatchFrac = 1.0
reg = 1e-10
modelInteract = LinearRegressionWithSGD.train(trainDataInteract, numIters, alpha,
miniBatchFrac, regParam=reg,
regType='l2', intercept=True)
labelsAndPredsInteract = valDataInteract.<COMPLETAR>
rmseValInteract = calcRMSE(labelsAndPredsInteract)
print ('Validation RMSE:\n\tBaseline = {0:.3f}\n\tLR0 = {1:.3f}\n\tLR1 = {2:.3f}\n\tLRGrid = ' +
'{3:.3f}\n\tLRInteract = {4:.3f}').format(rmseValBase, rmseValLR0, rmseValLR1,
rmseValLRGrid, rmseValInteract)
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# TEST Build interaction model (5b)
Test.assertTrue(np.allclose(rmseValInteract, 15.6894664683), 'incorrect value for rmseValInteract')
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# EXERCICIO
labelsAndPredsTest = testDataInteract.<COMPLETAR>
rmseTestInteract = calcRMSE(labelsAndPredsTest)
print ('Test RMSE:\n\tBaseline = {0:.3f}\n\tLRInteract = {1:.3f}'
.format(rmseTestBase, rmseTestInteract))
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# TEST Evaluate interaction model on test data (5c)
Test.assertTrue(np.allclose(rmseTestInteract, 16.3272040537),
'incorrect value for rmseTestInteract')