【发布时间】：2016-01-06 15:00:34
【问题描述】：
最近我需要使用来自 UCI https://archive.ics.uci.edu/ml/datasets/Optical+Recognition+of+Handwritten+Digits 的数据进行数字识别项目 我想使用来自 https://github.com/khiner/Linear-Discrimination-with-Perceptrons 的源代码。但我不想只是复制他的代码。因为我不知道如何在 python 中绘制错误图，所以我希望用 java 和 Matlab 重新编写它。有谁知道如何在 python 中绘制错误图和其他统计图，或者我在哪里可以找到用 java 和 Matlab 重写 python 的教程？
源代码：
from optparse import OptionParser
import random
class Perceptron(object):
def __init__(self, trainfile_string, testfile_string):
train_lines = open(trainfile_string, 'r').readlines()
test_lines = open(testfile_string, 'r').readlines()
# these vectors map a class number to a list of its corresponding
# train/test instances (int vectors)
self.train_vectors = {}
self.test_vectors = {}
self.num_features = len(train_lines[0].strip().split(',')) - 1
self.weights = {}
# initialize train_vectors and test_vectors.
# initialize weight vectors to random values in (-1, 1)
for n in xrange(10):
if n != 8:
self.train_vectors[n] = []
self.test_vectors[n] = []
self.weights[n] = [random.uniform(-1,1) for i in xrange(self.num_features)]
self.weights[n].append(1.0) # input bias
for line in train_lines:
vector = [int(x) for x in line.strip().split(',')]
if vector[-1] in (n, 8):
self.train_vectors[n].append(vector)
for line in test_lines:
vector = [int(x) for x in line.strip().split(',')]
if vector[-1] in (n, 8):
self.test_vectors[n].append(vector)
def run(self, max_epochs, rate, over_train=False, verbose=False):
"""For each class, train until there is no more improvement
(or accuracy is a perfect 1.0), then test the class using the
test file"""
for cls in self.weights.keys():
improvement = 1
epoch = 0
train_accuracy = 0
over_train_epochs = max_epochs
print '___________%dv%d____________' % (cls, 8)
if verbose:
print 'Training:'
epochs_set = False
while (not over_train and train_accuracy < 1.0 and \
improvement > 0.0 and epoch < max_epochs) \
or (over_train and epoch < over_train_epochs):
if not epochs_set and (improvement <= 0.0 or train_accuracy >= 1.0):
# if we're overtraining, train for twice as long as normal
over_train_epochs = 2*epoch
epochs_set = True
print 'over-training. improvement stopped at %d' % epoch
epoch = epoch + 1
self.train(cls, rate)
(c1, i1, c2, i2) = self.test(cls, train=True)
(old_accuracy, train_accuracy) = (train_accuracy, float(c1 + c2)/float(c1+ c2 + i1 + i2))
improvement = train_accuracy - old_accuracy
if verbose:
print 'Epoch %d, accuracy: %f, improvement: %f\n\n%s' % \
(epoch, train_accuracy, improvement, confusionMatrix(cls, c1, i1, c2, i2))
# done training. now test.
(c1, i1, c2, i2) = self.test(cls, train=False)
test_accuracy = float(c1 + c2)/float(c1+ c2 + i1 + i2)
print "Epochs: %d\nTraining accuracy: %f\nTest accuracy: %f\n\n%s" \
% (epoch, train_accuracy, test_accuracy, confusionMatrix(cls, c1, i1, c2, i2))
def train(self, cls, learning_rate):
"""Train perceptron to differentiate between cls and 8,
and return the trained weights weights"""
for vector in self.train_vectors[cls]:
(o, t) = self.getOandT(vector, cls)
if o == None or t == None:
continue
# adjust the weights (+1 for bias)
for i in xrange(self.num_features + 1):
self.weights[cls][i] += learning_rate*(t - o)*vector[i]
def test(self, cls, train):
"""Use the provided test data to test the trained weights
for a given class number vs. 8.
Returns a tuple representing a confusion matrix
eg: (8-correct, 8-incorrect, cls-correct, cls-incorrect)."""
if train:
vectors = self.train_vectors[cls]
else:
vectors = self.test_vectors[cls]
c1 = 0; # num examples classified correctly for 8
i1 = 0; # '' '' '' incorrectly for 8
c2 = 0; # '' '' '' correctly for cls
i2 = 0; # '' '' '' incorrectly for cls
for vector in vectors:
(o, t) = self.getOandT(vector, cls)
if o == None or t == None:
continue
elif o == 1 and t == 1:
c1 = c1 + 1
elif o == -1 and t == -1:
c2 = c2 + 1
elif o == -1 and t == 1:
i1 = i1 + 1
elif o == 1 and t == -1:
i2 = i2 + 1
return (c1, i1, c2, i2)
def getOandT(self, vector, cls):
"""Returns a tuple of o and t values, comparing cls to 8
-1 = cls, 1 = 8
None = provided instance vector is not 8 or the provided class (cls)"""
if vector[-1] == 8:
t = 1
elif vector[-1] == cls:
t = -1
else:
return (None, None)
total = 0.0
for i in xrange(self.num_features + 1):
total += self.weights[cls][i]*vector[i]
o = sgn(total)
return (o, t)
def confusionMatrix(cls, c1, i1, c2, i2):
return "Class\tCorrect\tIncorrect\n%d\t%d\t%d\n%d\t%d\t%d" %\
(cls, c2, i2, 8, c1, i1)
def sgn(val):
"""Returns 1 for val > 0 and -1 for val <= 0"""
if val > 0:
return 1
else:
return -1
if __name__ == "__main__":
parser = OptionParser()
parser.add_option("-n", "--train", dest="train_file", default="data/optdigits.tra", help="file with training data. default: 'data/optdigits.tra'")
parser.add_option("-t", "--test", dest="test_file", default="data/optdigits.tes", help="file with test data. default: 'data/optdigits.tes'")
parser.add_option("-e", "--epochs", dest="max_epochs", default=30, help="maximum number of epochs. default: 30")
parser.add_option("-r", "--rate", dest="rate", default=.2, help="learning rate. default: 0.2")
parser.add_option("-v", "--verbose", dest="verbose", default=False, help="would you like to print more detailed output?")
parser.add_option("-o", "--over-train", dest="over_train", default=False, help="if set to true, training will go for twice as many epochs as it takes to stop improving")
(options, args) = parser.parse_args()
verbose = options.verbose
perceptron = Perceptron(options.train_file, options.test_file)
perceptron.run(max_epochs=int(options.max_epochs), \
rate=float(options.rate), over_train=options.over_train, verbose=options.verbose)
【问题讨论】：
-
查看 matplolib 的图形绘制。你可以在这里找到例子：matplotlib.org/1.4.1/gallery.html