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@varunagrawal
Forked from akesling/mnist.py
Created February 16, 2017 21:37
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import os
import struct
import numpy as np
"""
Loosely inspired by http://abel.ee.ucla.edu/cvxopt/_downloads/mnist.py
which is GPL licensed.
"""
def read(dataset = "training", path = "."):
"""
Python function for importing the MNIST data set. It returns an iterator
of 2-tuples with the first element being the label and the second element
being a numpy.uint8 2D array of pixel data for the given image.
"""
if dataset is "training":
fname_img = os.path.join(path, 'train-images-idx3-ubyte')
fname_lbl = os.path.join(path, 'train-labels-idx1-ubyte')
elif dataset is "testing":
fname_img = os.path.join(path, 't10k-images-idx3-ubyte')
fname_lbl = os.path.join(path, 't10k-labels-idx1-ubyte')
else:
raise ValueError, "dataset must be 'testing' or 'training'"
# Load everything in some numpy arrays
with open(fname_lbl, 'rb') as flbl:
magic, num = struct.unpack(">II", flbl.read(8))
lbl = np.fromfile(flbl, dtype=np.int8)
with open(fname_img, 'rb') as fimg:
magic, num, rows, cols = struct.unpack(">IIII", fimg.read(16))
img = np.fromfile(fimg, dtype=np.uint8).reshape(len(lbl), rows, cols)
get_img = lambda idx: (lbl[idx], img[idx])
# Create an iterator which returns each image in turn
for i in xrange(len(lbl)):
yield get_img(i)
def show(image):
"""
Render a given numpy.uint8 2D array of pixel data.
"""
from matplotlib import pyplot
import matplotlib as mpl
fig = pyplot.figure()
ax = fig.add_subplot(1,1,1)
imgplot = ax.imshow(image, cmap=mpl.cm.Greys)
imgplot.set_interpolation('nearest')
ax.xaxis.set_ticks_position('top')
ax.yaxis.set_ticks_position('left')
pyplot.show()
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