buildCodebook(node.right, currentCode + "0")
def findCodeLength(nodes):
codeLength = 0.0
for node in nodes:
codeLength += len(node.code)*node.prob
return codeLength
remainingElements = [Node(prob=pList[x],index=x) for x in
xrange(0,len(pList))]
while len(remainingElements) > 1:
remainingElements = aggregate(remainingElements)
buildCodebook(remainingElements[0], "")
codeBook.sort(key=lambda x: x.index)
return ([x.code for x in codeBook], findCodeLength(codeBook))
if __name__ == "__main__":
import sys
import numpy
import PS1bin
if len(sys.argv)>1:
pList = numpy.array(eval(sys.argv[1]))
else:
pList = PS1bin.get_dist(5)
print 'pList = ', pList
(codeBook, codeLength) = huffman(pList)
print 'codeLength = ', codeLength
print 'codeBook:'
for x in codeBook:
print x
for node in nodes:
codeLength += len(node.code) * node.prob
return codeLength
remainingElements = [
Node(prob=pList[x], index=x) for x in xrange(0, len(pList))
]
while len(remainingElements) > 1:
remainingElements = aggregate(remainingElements)
buildCodebook(remainingElements[0], "")
codeBook.sort(key=lambda x: x.index)
return ([x.code for x in codeBook], findCodeLength(codeBook))
if __name__ == "__main__":
import sys
import numpy
import PS1bin
if len(sys.argv) > 1:
pList = numpy.array(eval(sys.argv[1]))
else:
pList = PS1bin.get_dist(5)
print 'pList = ', pList
(codeBook, codeLength) = huffman(pList)
print 'codeLength = ', codeLength
print 'codeBook:'
for x in codeBook:
print x
import sys
import numpy as np
import PS1bin
import PS11mycode
if __name__ == "__main__":
for n in [4, 5, 8, 10, 20]:
pp = PS1bin.get_dist(n)
ppl = len(pp)
print '\n\nchecking with pList = ', pp
print '...'
(codeBook, codeLength) = PS11mycode.huffman(pp.copy())
print 'your codeBook ( codeLength = ', codeLength, ' ):'
print codeBook
assert type(codeBook)==type([]), "code book is not a list"
assert ppl==len(codeBook), "wrong code book length"
for word in codeBook:
assert type(word)==type(''), "code word not a string"
for x in word:
assert x in ['0','1'], "code word has symbols other than 1 or 0"
for i in xrange(ppl):
for j in xrange(ppl):
if i != j:
assert not codeBook[i].startswith(codeBook[j]),\
"code book is not prefix-free"
s = 0.0
for i in xrange(ppl):
s += pp[i]*len(codeBook[i])
assert abs(s-codeLength)<1e-6, "computed and actual code length do not match"
assert PS1bin.chk1(pp,codeLength), "code book is far from optimal"
