def test(X_train, y_train, X_test, y_test, best_k):
classifier = KNearestNeighbor()
classifier.train(X_train, y_train)
y_test_pred = classifier.predict(X_test, k=best_k)
# Compute and display the accuracy
num_correct = np.sum(y_test_pred == y_test)
accuracy = float(num_correct) / len(y_test)
print 'Best k=%d' % best_k
print 'Got %d / %d correct => accuracy: %f' % (num_correct, len(y_test),
accuracy)
def cross_validation(train_data, train_label):
"""交叉验证的方式选择最优的超参数k"""
num_folds = 5
k_choices = [1, 3, 5, 8, 10, 12, 15, 20, 50, 100]
# 任务：
# 将训练数据切分，训练样本和对应的样本标签包含在数组
# x_train_folds 和 y_train_folds 之中，数组的长度为num_folds
# 其中y_train_folds[i] 是一个矢量，表示矢量x_train_folds[i]中所有样本的标签
# 提示：可以尝试使用numpy的 array_spilt 方法
x_train_folds = np.array_split(train_data, num_folds)
y_train_folds = np.array_split(train_label, num_folds)
# 我们将不同k值下的准确率保存在一个字典中。交叉验证之后，k_to_accuracies[k]保存了一个
# 长度为num_folds的list，值为k值下的准确率
k_to_accuracies = {}
# 任务：
# 通过k折的交叉验证找到最佳k值。对于每一个k值，执行KNN算法num_folds次，每一次执行中，选择一折为验证集
# 其它折为训练集。将不同k值在不同折上的验证结果保存在k_to_accuracies字典中
classifiers = KNearestNeighbor()
for k in k_choices:
accuracies = np.zeros(num_folds)
for fold in range(num_folds):
temp_x = x_train_folds.copy()
temp_y = y_train_folds.copy()
# 组成验证集
x_validate_fold = temp_x.pop(fold)
y_validate_fold = temp_y.pop(fold)
# 组成训练集
x_temp_train_fold = np.array([x for x_fold in temp_x for x in x_fold])
y_temp_train_fold = np.array([y for y_fold in temp_y for y in y_fold])
classifiers.train(x_temp_train_fold, y_temp_train_fold)
# 进行验证
y_test_predicted = classifiers.predict(x_validate_fold, k, 0)
num_correct = np.sum(y_test_predicted == y_validate_fold)
accuracy = float(num_correct) / y_validate_fold.shape[0]
accuracies[fold] = accuracy
k_to_accuracies[k] = accuracies
# 输出准确率
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
# 画图显示所有的精确度散点
for k in k_choices:
accuracies = k_to_accuracies[k]
plt.scatter([k]*len(accuracies), accuracies)
# plot the trend line with error bars that correspond to standard
# 画出在不同k值下，误差均值和标准差
accuracies_mean = np.array([np.mean(k_to_accuracies[k]) for k in sorted(k_to_accuracies)])
accuracies_std = np.array([np.std(k_to_accuracies[k]) for k in sorted(k_to_accuracies)])
plt.errorbar(k_choices, accuracies_mean, yerr=accuracies_std)
plt.title('Cross-validation on k')
plt.xlabel('k')
plt.ylabel('Cross-validation accuracy')
plt.show()
def main():
X_train, y_train, X_test, y_test = load_CIFAR10('../cifar-10-batches-py')
num_training = 48000
mask = list(range(num_training))
X_train = X_train[mask]
y_train = y_train[mask]
num_test = 1000
mask = list(range(num_test))
X_test = X_test[mask]
y_test = y_test[mask]
# Reshape the image data into rows
print(X_train.shape)
'''
(48000, 32, 32, 3)
'''
X_train = np.reshape(X_train, (X_train.shape[0], -1))
print(X_train.shape)
'''
(48000, 3072)
'''
X_test = np.reshape(X_test, (X_test.shape[0], -1))
print(X_train.shape, X_test.shape)
'''
(48000, 3072) (1000, 3072)
'''
classifier = KNearestNeighbor()
classifier.train(X_train, y_train)
y_test_pred = classifier.predict(X_test, k=5)
print(y_test_pred)
# Compute and display the accuracy
num_correct = np.sum(y_test_pred == y_test)
accuracy = float(num_correct) / num_test
print('Got %d / %d correct => accuracy: %f' %
(num_correct, num_test, accuracy))
'''
acc_k = np.zeros((len(k_choices), num_folds), dtype=np.float)
################################################################################
# TODO: #
# Perform k-fold cross validation to find the best value of k. For each #
# possible value of k, run the k-nearest-neighbor algorithm num_folds times, #
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
for ik, k in enumerate(k_choices):
for i in range(num_folds):
train_set = np.concatenate((X_train_folds[:i] + X_train_folds[i + 1:]))
label_set = np.concatenate((y_train_folds[:i] + y_train_folds[i + 1:]))
classifier.train(train_set, label_set)
y_pred_fold = classifier.predict(X_train_folds[i], k=k, num_loops=0)
num_correct = np.sum(y_pred_fold == y_train_folds[i])
acc_k[ik, i] = float(num_correct) / num_split
k_to_accuracies[k] = acc_k[ik]
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
# plot the raw observations
fig = plt.figure()
for k in k_choices:
# 交叉验证：执行knn算法num_folds次，每次选择一折为验证集，其他折为训练集，将准确率保存在k_to_accuracy中。
classifier = KNearestNeighbor()
for k in k_choices:
accuracies = np.zeros(num_folds)
for fold in xrange(num_folds):
temp_X = X_train_folds[:]
temp_y = y_train_folds[:]
X_validate_fold = temp_X.pop(fold)
y_validate_fold = temp_y.pop(fold)
temp_X = np.array([y for x in temp_X for y in x])
temp_y = np.array([y for x in temp_y for y in x])
classifier.train(temp_X, temp_y)
y_test_pred = classifier.predict(X_validate_fold, k = k)
num_correct = np.sum(y_test_pred == y_validate_fold)
accuracy = float(num_correct) / len(y_test_pred)
accuracies[fold] = accuracy
k_to_accuracies[k] = accuracies
# 输出准确率
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# 画图
for k in k_choices:
accuracies = k_to_accuracies[k]
plt.scatter([k] * len(accuracies), accuracies)
for k in k_choices:
acc = np.zeros((num_folds))
for f in xrange(num_folds):
X_current_fold = list(X_train_folds)
del X_current_fold[f]
X_current_fold = np.concatenate(X_current_fold)
y_current_fold = list(y_train_folds)
del y_current_fold[f]
y_current_fold = np.concatenate(y_current_fold)
classifier = KNearestNeighbor()
classifier.train(X_current_fold, y_current_fold)
y_current_predict = classifier.predict(X_train_folds[f],
k,
num_loops=0)
num_correct = np.sum(y_current_predict == y_train_folds[f])
acc[f] = float(num_correct) / num_test
k_to_accuracies[k] = acc
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# plot the raw observations
for k in k_choices:
accuracies = k_to_accuracies[k]
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
for k in k_choices: # for each k
for n in range(num_folds): # for each nth fold
other_folds = [x for x in range(num_folds) if x != n]
X_test_fold = X_train_folds[n]
y_test_fold = y_train_folds[n] # we have the test data
X_train_other_folds = np.concatenate((X_train_folds[other_folds]),
axis=0)
y_train_other_folds = np.concatenate((y_train_folds[other_folds]),
axis=0)
classifier = KNearestNeighbor()
classifier.train(X_train_other_folds, y_train_other_folds)
y_pred_fold = classifier.predict(X=X_test_fold, k=k)
num_correct_fold = np.sum(y_pred_fold == y_test_fold)
acc_fold = float(num_correct_fold) / len(y_test_fold)
k_to_accuracies.setdefault(k, []).append(acc_fold)
#print(k_to_accuracies)
#print("for k=%d choice, the accuracy= %f" % (k, acc_fold))
pass
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
print("mean for k=%d is %f1" % (k, np.mean(k_to_accuracies[k])))
X_train_instance_list = X_train_folds[:idx_fold] + X_train_folds[
idx_fold + 1:]
y_train_instance_list = y_train_folds[:idx_fold] + y_train_folds[
idx_fold + 1:]
X_train_instance = np.concatenate(X_train_instance_list)
y_train_instance = np.concatenate(y_train_instance_list)
# train
classifier.train(X_train_instance, y_train_instance)
# cross-validation
# dists_cv = classifier.compute_distances_no_loops(X_cv_instance)
# y_cv_pred = classifier.predict_labels(dists_cv, k=k_cv)
y_cv_pred = classifier.predict(X_cv_instance, k=k_cv)
num_correct = np.sum(y_cv_pred == y_cv_instance)
accuracy = float(num_correct) / len(y_cv_instance)
k_to_accuracies[k_cv].append(accuracy)
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
# In[ ]:
for k in k_choices:
accuracies = k_to_accuracies[k]
plt.scatter([k] * len(accuracies), accuracies)
# plot the trend line with error bars that correspond to standard deviation
accuracies_mean = np.array(
[np.mean(v) for k, v in sorted(k_to_accuracies.items())])
accuracies_std = np.array(
[np.std(v) for k, v in sorted(k_to_accuracies.items())])
plt.errorbar(k_choices, accuracies_mean, yerr=accuracies_std)
plt.title('Cross-validation on k')
plt.xlabel('k')
plt.ylabel('Cross-validation accuracy')
plt.show()
# In[ ]:
# Based on the cross-validation results above, choose the best value for k,
# retrain the classifier using all the training data, and test it on the test
# data. You should be able to get above 28% accuracy on the test data.
best_k = 1
classifier = KNearestNeighbor()
classifier.train(X_train, y_train)
y_test_pred = classifier.predict(X_test, k=best_k)
# Compute and display the accuracy
num_correct = np.sum(y_test_pred == y_test)
accuracy = float(num_correct) / num_test
print 'Got %d / %d correct => accuracy: %f' % (num_correct, num_test, accuracy)
dists2 = classifier.compute_distances_two_loops(X_test)
dists1 = classifier.compute_distances_one_loop(X_test)
dists0 = classifier.compute_distances_no_loops(X_test)
dists = classifier.compute_distances_no_loops(X_test)
print dists.shape
# Now implement the function predict_labels and run the code below:
# We use k = 1 (which is Nearest Neighbor).
y_test_pred = classifier.predict_labels(dists, k=1)
# Compute and print the fraction of correctly predicted examples
num_correct = np.sum(y_test_pred == y_test)
accuracy = float(num_correct) / num_test
print 'Got %d / %d correct => accuracy: %f' % (num_correct, num_test, accuracy)
classifier.predict(X_test, k=1, num_loops=0)
classifier.pridict_currency(X_test, y_test, k=1, num_loops=0)
# cross validation
num_folds = 5
k_choices = [1, 3, 5, 8, 10, 12, 15, 20, 50, 100]
X_train_folds = []
y_train_folds = []
X_train_folds = np.array_split(X_train, num_folds)
y_train_folds = np.array_split(y_train, num_folds)
k_to_accuracies = {}
for k in k_choices:
validation_accuracies = []
for i in range(num_folds):
current_x_test = X_train_folds[i]
X_train_folds = np.array_split(X_train_temp, num_folds)
y_train_folds = np.array_split(y_train_temp, num_folds)
print(X_train_folds[4])
k_to_accuracies = {}
num_test = X_train_folds[0].shape[0]
for j in range(len(k_choices)):
k = k_choices[j]
for i in range(1,num_folds+1):
X_train_temp = np.concatenate((X_train_folds[num_folds-i],X_train_folds[num_folds-i-1],X_train_folds[num_folds-i-2],X_train_folds[num_folds-i-3]),axis = 0)
y_train_temp = np.concatenate((y_train_folds[num_folds-i],y_train_folds[num_folds-i-1],y_train_folds[num_folds-i-2],y_train_folds[num_folds-i-3]))
X_test_temp = X_train_folds[num_folds-i-4]
y_test_temp = y_train_folds[num_folds-i-4]
classifier.train(X_train_temp, y_train_temp)
y_test_pred = classifier.predict(X_test_temp, k=k)
num_correct = np.sum(y_test_pred == y_test_temp)
accuracy = float(num_correct) / num_test
k_to_accuracies.setdefault(k,[]).append(accuracy)
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
for k in k_choices:
accuracies = k_to_accuracies[k]
plt.scatter([k] * len(accuracies), accuracies)
# plot the trend line with error bars that correspond to standard deviation
accuracies_mean = np.array([np.mean(v) for k,v in sorted(k_to_accuracies.items())])
accuracies_std = np.array([np.std(v) for k,v in sorted(k_to_accuracies.items())])
plt.errorbar(k_choices, accuracies_mean,yerr=accuracies_std)
y_train_folds = []
X_train_folds = np.array_split(classifier.X_train, num_folds)
y_train_folds = np.array_split(classifier.y_train, num_folds)
pass
k_to_accuracies = {}
X_val = X_train_folds[num_folds-1]
y_val = y_train_folds[num_folds-1]
for k in k_choices:
k_to_accuracies[k] = []
for i in range(num_folds):
knn = KNearestNeighbor()
knn.train(X_train_folds[i], y_train_folds[i])
y_predict = knn.predict(X_val, k = k)
acc = np.mean(y_predict == y_val)
k_to_accuracies[k].append(acc)
print('k_to_accuracies')
print(k_to_accuracies)
pass
for k in k_choices:
accuracies = k_to_accuracies[k]
plt.scatter([k] * len(accuracies), accuracies)
plt.show()
for k,v in sorted(k_to_accuracies.items()):
print(k, v)
# values of k in the k_to_accuracies dictionary. #
################################################################################
# *****START OF YOUR CODE (DO NOT DELETE/MODIFY THIS LINE)*****
num_per_fold = len(X_train)/num_folds
X_valid_fold = X_train_folds[-1]
y_valid_fold = y_train_folds[-1]
X_train_folds = X_train_folds[:-1]
y_train_folds = y_train_folds[:-1]
accuracies = []
for i in range(len(k_choices)):
accuracies = [0.0] * (num_folds - 1)
for n in range(num_folds-1):
classifier.train(X_train_folds[n], y_train_folds[n])
y_pred_folds = classifier.predict(
X_valid_fold, k=k_choices[i], num_loops=0)
num_correct = np.sum(y_valid_fold == y_pred_folds)
accuracies[n] = float(num_correct) / num_per_fold
k_to_accuracies.update({k_choices[i]: accuracies})
pass
# *****END OF YOUR CODE (DO NOT DELETE/MODIFY THIS LINE)*****
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
import numpy as np
import matplotlib.pyplot as plt
from cs231n.data_utils import load_CIFAR10
from cs231n.classifiers import KNearestNeighbor
#Load data
cifar10_dir = 'cs231n/datasets/cifar-10-batches-py'
X_tre, y_tre, X_te, y_te = load_CIFAR10(cifar10_dir)
X_tre_rows = X_tre.reshape(X_tre.shape[0], 32 * 32 * 3)
X_te_rows = X_te.reshape(X_te.shape[0], 32 * 32 * 3)
X_val_rows = X_tre_rows[:1000, :]
y_val_rows = y_tre[:1000]
X_tre_rows = X_tre_rows[1000:, :]
y_tre = y_tre[:1000]
val_acc = []
for k in [1, 3, 5, 10, 20, 50, 100]:
knn = KNearestNeighbor()
knn.train(X_tre, y_tre)
y_val_predict = knn.predict(X_val_rows, k=k)
acc = np.mean(y_val_predict == y_val_rows)
print 'accuracy: %f' % (acc * 100)
val_acc.append((k, acc))
k_to_accuracies = {}
for i in range(len(k_choices)):
accuracy = []
for j in range(num_folds):
X_train_ = np.reshape(
np.asarray(X_train_folds[:j] + X_train_folds[j + 1:]), (-1, 3072))
y_train_ = np.reshape(
np.asarray(y_train_folds[:j] + y_train_folds[j + 1:]), (4000, -1))
X_test_ = np.asarray(X_train_folds[j])
y_test_ = np.asarray(y_train_folds[j])
from cs231n.classifiers import KNearestNeighbor
classifier = KNearestNeighbor()
classifier.train(X_train_, y_train_)
y_test_pred = classifier.predict(X_test_, k=k_choices[i], num_loops=0)
accuracy.append(np.sum(y_test_pred == y_test_) / y_test_.shape[0])
k_to_accuracies[k_choices[i]] = accuracy
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
# plot the raw observations
for k in k_choices:
accuracies = k_to_accuracies[k]
plt.scatter([k] * len(accuracies), accuracies)
# plot the trend line with error bars that correspond to standard deviation
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
for k in k_choices:
k_to_accuracies[k] = []
for f in xrange(num_folds):
X_train_val = np.concatenate(
[j for i, j in enumerate(X_train_folds) if i != f])
y_train_val = np.concatenate(
[j for i, j in enumerate(y_train_folds) if i != f])
classifier = KNearestNeighbor()
classifier.train(X_train_val, y_train_val)
for k in k_choices:
y_pred = classifier.predict(X_train_folds[f], k)
num_correct = np.sum(y_pred == y_train_folds[f])
accuracy = float(num_correct) / float(y_train_folds[f].shape[0])
k_to_accuracies[k].append(accuracy)
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# In[17]:
# possible value of k, run the k-nearest-neighbor algorithm num_folds times, #
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
#pass
for k_ in k_choices:
k_to_accuracies.setdefault(k_, [])
for i in range(num_folds):
classifier = KNearestNeighbor()
X_val_train = np.vstack(X_train_folds[:i] + X_train_folds[i + 1:])
y_val_train = np.vstack(y_train_folds[:i] + y_train_folds[i + 1:])
y_val_train = y_val_train[:, 0] ##reshape
classifier.train(X_val_train, y_val_train)
for k_ in k_choices:
y_val_pred = classifier.predict(X_train_folds[i], k=k_, num_loops=2)
num_correct = np.sum(y_val_pred == y_train_folds[i][:, 0])
num_correct = np.sum(y_val_pred == y_train_folds[i])
accuracy = float(num_correct) / len(y_val_pred)
k_to_accuracies[k_].append(accuracy) ##try
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# In[ ]:
# possible value of k, run the k-nearest-neighbor algorithm num_folds times, #
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
# pass
for k_ in k_choices:
k_to_accuracies.setdefault(k_, [])
for i in range(num_folds):
classifier = KNearestNeighbor()
X_val_train = np.vstack(X_train_folds[0:i] + X_train_folds[i+1:])
y_val_train = np.vstack(y_train_folds[0:i] + y_train_folds[i+1:])
y_val_train = y_val_train[:,0]
classifier.train(X_val_train, y_val_train)
for k_ in k_choices:
y_val_pred = classifier.predict(X_train_folds[i], k=k_)
num_correct = np.sum(y_val_pred == y_train_folds[i][:,0])
accuracy = float(num_correct) / len(y_val_pred)
k_to_accuracies[k_] = k_to_accuracies[k_] + [accuracy]
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# plot the raw observations
for k in k_choices:
accuracies = k_to_accuracies[k]
# kValue = [3]
kAccuracies = []
# print(xTrain)
for ptr, k in enumerate(kValue):
kValueAcc = []
for i in xrange(0, cvFold):
xValid = xTrain[i]
yValid = yTrain[i]
xTrainCV = xTrain[np.arange(cvFold) != i]
yTrainCV = yTrain[np.arange(cvFold) != i]
xTrainCV = np.reshape(
xTrainCV, (lengthTrain - lengthTrain / cvFold, xTrainCV.shape[2]))
yTrainCV = np.reshape(yTrainCV, (lengthTrain - lengthTrain / cvFold, ))
clsfr.train(xTrainCV, yTrainCV)
yPredict = clsfr.predict(xValid, k=k)
acc = np.sum(yPredict == yValid)
kValueAcc.append([float(acc) / (lengthTrain / cvFold)])
kAccuracies.append(kValueAcc)
print([np.mean(i) for i in kAccuracies])
plt.figure()
x = np.array(kValue)
y = np.array([np.mean(i) for i in kAccuracies])
print(x.shape)
print(y.shape)
plt.errorbar(np.array(kValue),
np.array([np.mean(i) for i in kAccuracies]),
yerr=np.array([np.std(i) for i in kAccuracies]))
plt.show()
# values of k in the k_to_accuracies dictionary. #
################################################################################
for k in k_choices:
for n in range(num_folds):
# Concat all our folds together except for the nth fold for training.
current_train_fold_x = np.concatenate(tuple([X_train_folds[i] for i in range(num_folds) if i!=n]))
current_train_fold_y = np.concatenate(tuple([y_train_folds[i] for i in range(num_folds) if i!=n]))
# Select the held out fold to be our test data.
current_valid_fold_x = X_train_folds[n]
current_valid_fold_y = y_train_folds[n]
classifier.train(current_train_fold_x, current_train_fold_y)
# Perform prediction on our test set, default is to use no loop version.
y_test_pred = classifier.predict(current_valid_fold_x, k=k)
# Evaluate and store in k_to_accuracies dict.
num_correct = np.sum(y_test_pred == current_valid_fold_y)
if k not in k_to_accuracies:
k_to_accuracies[k] = [float(num_correct) / current_test_fold_x.shape[0]]
else:
k_to_accuracies[k].append(float(num_correct) / current_test_fold_x.shape[0])
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
num_folds = 5
k_choices = [1, 3, 5, 8, 10, 12, 15, 20, 50, 100]
X_train_folds = []
y_train_folds = []
X_train_folds = np.array_split(X_train, num_folds)
y_train_folds = np.array_split(y_train, num_folds)
k_to_accuracies = {}
for k in k_choices:
k_to_accuracies[k] = []
#for f in xrange(num_folds):
# X_train_val = np.concatenate([j for i,j in enumerate(X_train_folds) if i!=f])
# y_train_val = np.concatenate([j for i,j in enumerate(y_train_folds) if i!=f])
X_train_val = np.concatenate([j for i,j in enumerate(X_train_folds) if i!=0])
y_train_val = np.concatenate([j for i,j in enumerate(y_train_folds) if i!=0])
classifier.train(X_train_val, y_train_val)
for k in k_choices:
y_pred = classifier.predict(X_train_folds[f], k)
num_correct = np.sum(y_pred == y_train_folds[f])
accuracy = float(num_correct) / float(y_train_folds[f].shape[0])
k_to_accuracies[k].append(accuracy)
# Perform k-fold cross validation to find the best value of k. For each #
# possible value of k, run the k-nearest-neighbor algorithm num_folds times, #
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
# *****START OF YOUR CODE (DO NOT DELETE/MODIFY THIS LINE)*****
for k in k_choices:
k_to_accuracies[k] = []
for i in range(5):
classifier_k_fold = KNearestNeighbor()
classifier_k_fold.train(
np.delete(X_train_folds, i, axis=0).reshape(-1, 3072),
np.delete(y_train_folds, i, axis=0).reshape(-1))
y_predict_k_fold = classifier_k_fold.predict(X_train_folds[i], k=k)
correct_count = np.sum(y_predict_k_fold == y_train_folds[i])
k_to_accuracies[k].append(
float(correct_count / y_predict_k_fold.shape[0]))
# *****END OF YOUR CODE (DO NOT DELETE/MODIFY THIS LINE)*****
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
# %%
# plot the raw observations
for k in k_choices:
accuracies = k_to_accuracies[k]
accuracy = float(num_correct) / num_test
k_to_accuracies[k].append(accuracy)
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# plot the trend line with error bars that correspond to standard deviation
accuracies_mean = np.array([np.mean(v) for k,v in sorted(k_to_accuracies.items())])
accuracies_std = np.array([np.std(v) for k,v in sorted(k_to_accuracies.items())])
plt.errorbar(k_choices, accuracies_mean, yerr=accuracies_std)
plt.title('Cross-validation on k')
plt.xlabel('k')
plt.ylabel('Cross-validation accuracy')
plt.show()
# Based on the cross-validation results above, choose the best value for k,
# retrain the classifier using all the training data, and test it on the test
# data.
best_k = 6
classifier = KNearestNeighbor()
classifier.train(X_train, y_train)
y_test_pred = classifier.predict(X_test, k=best_k)
# Compute and display the accuracy
num_correct = np.sum(y_test_pred == y_test)
accuracy = float(num_correct) / num_test
print 'Got %d / %d correct => accuracy: %f' % (num_correct, num_test, accuracy)
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
### study np.vstack.. np.hstack..
for ck in k_choices:
k_to_accuracies[ck] = []
for it in range(num_folds):
X_train_cv = np.vstack(X_train_folds[0:it]+X_train_folds[it+1:])
X_test_cv = X_train_folds[it]
y_train_cv = np.hstack(y_train_folds[0:it]+y_train_folds[it+1:])
y_test_cv = y_train_folds[it]
for ck in k_choices:
classifier.train(X_train_cv,y_train_cv)
y_predict = classifier.predict(X_test_cv,k=ck)
k_to_accuracies[ck].append(np.mean(y_predict==y_test_cv))
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
# for k in sorted(k_to_accuracies):
# for accuracy in k_to_accuracies[k]:
# print 'k = %d, accuracy = %f' % (k, accuracy)
# plot the raw observations
for k in k_choices:
accuracies = k_to_accuracies[k]
num_folds = 5
k_choices = [1, 3, 5, 8, 10, 12, 15, 20, 50, 100]
X_train_folds = []
y_train_folds = []
X_train_folds = np.array_split(X_train, num_folds)
y_train_folds = np.array_split(y_train, num_folds)
k_to_accuracies = {k: np.zeros(num_folds) for k in k_choices}
for k in k_to_accuracies:
# Training phase
for i in range(num_folds):
X_train = X_train_folds[i]
y_test_pred = classifier.predict(X_test, k=k, num_loops=0)
#print("y_test_pred[0:4]: ", y_test_pred[0:4])
#print("y_train_folds[",i,",0:4]: ", y_train_folds[i][0:4])
num_correct = np.sum(y_test_pred == y_test)
print("k: ", k, " num_correct: ", num_correct, " len(y_test_pred): ",
len(y_test_pred))
accuracy = float(num_correct) / len(y_test_pred)
print("accuracy: ", accuracy)
#k_to_accuracies[k][i] = accuracy
# Validation phase - need to make this different from training
# y_val_pred = classifier.predict(X_train_folds[num_folds-1], k=k, num_loops=0)
# num_correct = np.sum(y_val_pred == y_train_folds[num_folds-1])
# accuracy = float(num_correct) / len(y_val_pred)
# k_to_accuracies[k][num_folds-1] = accuracy
# print("k_to_accuracies[",k,"]: ", k_to_accuracies[k])
# Perform k-fold cross validation to find the best value of k. For each #
# possible value of k, run the k-nearest-neighbor algorithm num_folds times, #
# where in each case you use all but one of the folds as training data and the #
# last fold as a validation set. Store the accuracies for all fold and all #
# values of k in the k_to_accuracies dictionary. #
################################################################################
for k in k_choices:
accuracy = []
for fold in range(num_folds):
Xval = X_train_folds[fold]
yval = y_train_folds[fold]
Xtrain = X_train_folds[range(num_folds)!=fold]
ytrain = y_train_folds[range(num_folds)!=fold]
import ipdb; ipdb.set_trace()
classifier.train(Xtrain,ytrain)
predictions = classifier.predict(Xval,k)
acc = np.sum(predictions==yval)/float(yval.shape[0])
accuracy.append(acc)
k_to_accuracies[k] = accuracy
################################################################################
# END OF YOUR CODE #
################################################################################
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print 'k = %d, accuracy = %f' % (k, accuracy)
# In[ ]:
# *****START OF YOUR CODE (DO NOT DELETE/MODIFY THIS LINE)*****
for k in k_choices:
k_to_accuracies[k] = []
for i in range(num_folds):
X_train_ = []
y_train_ = []
for j in range(num_folds):
if j!=i :
X_train_.extend(X_train_folds[j])
y_train_.extend(y_train_folds[j])
classifier = KNearestNeighbor()
classifier.train(np.array(X_train_), np.array(y_train_))
X_val = np.array(X_train_folds[i])
for k in k_choices:
y_val_pred = classifier.predict(X_val,k=k)
accuracy_val = np.mean(y_train_folds[i]== y_val_pred)
k_to_accuracies[k].append(accuracy_val)
# pass
# *****END OF YOUR CODE (DO NOT DELETE/MODIFY THIS LINE)*****
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))
X_train_folds = []
y_train_folds = []
X_train_folds = np.array_split(
X_train, num_folds) # (50000,3072) ==> (10000,3072)로 5(num_folds)개
y_train_folds = np.array_split(y_train, num_folds)
k_to_accuracies = {}
for k_val in k_choices:
k_to_accuracies[k_val] = []
for i in range(num_folds):
# print 'Cross-validation :'+ str(i)
X_train_cycle = np.concatenate(
[f for j, f in enumerate(X_train_folds) if j != i])
y_train_cycle = np.concatenate(
[f for j, f in enumerate(y_train_folds) if j != i])
X_val_cycle = X_train_folds[i]
y_val_cycle = y_train_folds[i]
knn = KNearestNeighbor()
knn.train(X_train_cycle, y_train_cycle)
y_val_pred = knn.predict(X_val_cycle, k_val)
num_correct = np.sum(y_val_cycle == y_val_pred)
k_to_accuracies[k_val].append(
float(num_correct) / float(len(y_val_cycle)))
# Print out the computed accuracies
for k in sorted(k_to_accuracies):
for accuracy in k_to_accuracies[k]:
print('k = %d, accuracy = %f' % (k, accuracy))