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added result array output loop in main for alg3; fixed alg3 and alg4 set... #11

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added result array output loop in main for alg3; fixed alg3 and alg4 set... #11

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added result array output loop in main for alg3; fixed alg3 and alg4 …
charlesmjenkins Apr 26, 2015
3516e96
Added header block, function headers, and some basic comments
charlesmjenkins Apr 26, 2015
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111 changes: 91 additions & 20 deletions projects/project1/project1algorithms.py
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Original file line number Diff line number Diff line change
@@ -1,3 +1,21 @@
# PROJECT GROUP 21 - PROJECT 1
# ---------------------------------------
# Members: Albert Le
# <leal@onid.oregonstate.edu>
#
# Charles Jenkins
# <jenkinch@onid.oregonstate.edu>
#
# Colin Bradford
# <bradfoco@onid.oregonstate.edu>
#
# Class: CS325 Analysis of Algorithms
#
# Description: Program uses four different
# algorithms to find the maximum subarray
# of a given array.
# ---------------------------------------

import sys
import math
import re
Expand All @@ -10,6 +28,16 @@

results = [[],[],[],[]]

# ---------------------------------------
# Name: max_subarray_algorithm1
#
# Description: Finds max subarray using
# enumeration.
#
# Receives: array
#
# Returns: max subarray
# ---------------------------------------
def max_subarray_algorithm1(array):
max_array = current_sum = start = end = 0
for i in range(0, len(array)):
Expand All @@ -24,7 +52,17 @@ def max_subarray_algorithm1(array):
start = i
end = k+1
return array[start:end]


# ---------------------------------------
# Name: max_subarray_algorithm2
#
# Description: Finds max subarray using
# better enumeration.
#
# Receives: array
#
# Returns: max subarray
# ---------------------------------------
def max_subarray_algorithm2(array):
max_array = current_sum = start = end = 0
for i in range(0, len(array)):
Expand All @@ -37,7 +75,17 @@ def max_subarray_algorithm2(array):
start = i
end = j+1
return array[start:end]


# ---------------------------------------
# Name: max_subarray_algorithm3
#
# Description: Finds max subarray using
# divide and conquer.
#
# Receives: array
#
# Returns: max subarray sum
# ---------------------------------------
def max_subarray_algorithm3(array):
current_sum = start = end = 0
if len(array) == 0:
Expand All @@ -60,10 +108,18 @@ def max_subarray_algorithm3(array):
if current_sum > right_max:
right_max = current_sum
end = i
print start
print end
return max(max(left_array,right_array),(left_max+right_max))


# ---------------------------------------
# Name: max_subarray_algorithm4
#
# Description: Finds max subarray using
# dynamic programming.
#
# Receives: array
#
# Returns: max subarray
# ---------------------------------------
def max_subarray_algorithm4(array):
max_array = current_sum = start = end = 0
for i in range(0,len(array)):
Expand All @@ -78,47 +134,62 @@ def max_subarray_algorithm4(array):
start = 0
return array[start:end]

#main function
# Main Function
if __name__ == '__main__':
args = sys.argv
if len(args) == 2:
# Process test file and check for correctness for given algorithm arg
with open("./MSS_Problems.txt","r") as f:
file = f.read() #bad if taking in big file
file = f.read() # Bad if taking in big file
reg = "(\[.*\])(?:\n|\r\n)(\[.*\])(?:\n|\r\n)(\d+)"
#reg = "(\[.*\])(?:\n|\r\n)"

for m in re.findall(reg,file):
if m == None: continue
array = eval(m[0]) #interpret the square bracketed stuff as python list
solution = int(m[2]) #cast the string number to an int
array = eval(m[0]) # Interpret the square bracketed stuff as python list
solution = int(m[2]) # Cast the string number to an int
print array
result = 0

if int(args[1]) == 1:
result_array = max_subarray_algorithm1(array)
print result_array
result = sum(result_array)

if int(args[1]) == 2:
result_array = max_subarray_algorithm2(array)
print result_array
result = sum(result_array)

if int(args[1]) == 3:
result = max_subarray_algorithm3(array)
#print result_array
#result = sum(result_array)
for i in range(0,len(array)-1):
check = 0
j = i
while check != result and j <= len(array)-1:
check += array[j]
j += 1
if check == result:
break
print array[i:j]

if int(args[1]) == 4:
result_array = max_subarray_algorithm4(array)
print result_array
result = sum(result_array)

if result == solution:
print "Correct: %s==%s"%(result, solution)
else:
print "Wrong: %s!=%s"%(result, solution)
else:
# Time and plot results of all algorithms for random arrays of size n
reps = 10
test = 1
for i in range(0,len(sizes1)):
n = sizes1[i]
setup1 = "import random;from __main__ import max_subarray_algorithm1;array = [random.randint(-1000, 1000) for i in xrange(%s)]"%(n)
test1 = "max_subarray_algorithm1(array)" #timeit interprets strings passed to it as python code and runs them
test1 = "max_subarray_algorithm1(array)" # timeit interprets strings passed to it as python code and runs them
result1 = timeit.timeit(test1, setup=setup1, number=reps)
results[0].append(result1)
r = [float(math.log(o)) for o in results[0]]
Expand All @@ -137,8 +208,8 @@ def max_subarray_algorithm4(array):

for i in range(0,len(sizes2)):
n = sizes2[i]
setup3 = "import random;from __main__ import max_subarray_algorithm2;array = [random.randint(-1000, 1000) for i in xrange(%s)]"%(n)
test3 = "max_subarray_algorithm2(array)"
setup3 = "import random;from __main__ import max_subarray_algorithm3;array = [random.randint(-1000, 1000) for i in xrange(%s)]"%(n)
test3 = "max_subarray_algorithm3(array)"
result3 = timeit.timeit(test3, setup=setup3, number=reps)
results[2].append(result3)
r = [float(math.log(o)) for o in results[2]]
Expand All @@ -147,18 +218,18 @@ def max_subarray_algorithm4(array):

for i in range(0,len(sizes2)):
n = sizes2[i]
setup4 = "import random;from __main__ import max_subarray_algorithm2;array = [random.randint(-1000, 1000) for i in xrange(%s)]"%(n)
test4 = "max_subarray_algorithm2(array)"
setup4 = "import random;from __main__ import max_subarray_algorithm4;array = [random.randint(-1000, 1000) for i in xrange(%s)]"%(n)
test4 = "max_subarray_algorithm4(array)"
result4 = timeit.timeit(test4, setup=setup4, number=reps)
results[3].append(result4)
r = [float(math.log(o)) for o in results[3]]
coefficient = math.exp(numpy.polyfit(sizes2, r, 1)[0])
print 'algorithm 4: ' + str(coefficient)

algorithm1,= mat.pyplot.loglog(sizes1,results[0], label='algorithm 1')
algorithm2,= mat.pyplot.loglog(sizes2,results[1], label='algorithm 2')
algorithm3,= mat.pyplot.loglog(sizes2,results[2], label='algorithm 3')
algorithm4,= mat.pyplot.loglog(sizes2,results[3], label='algorithm 4')
algorithm1 = mat.pyplot.loglog(sizes1,results[0], label='algorithm 1')
algorithm2 = mat.pyplot.loglog(sizes2,results[1], label='algorithm 2')
algorithm3 = mat.pyplot.loglog(sizes2,results[2], label='algorithm 3')
algorithm4 = mat.pyplot.loglog(sizes2,results[3], label='algorithm 4')
plt.title('loglog plot of runtime vs. array size',fontsize=10)
plt.ylabel('log(runtime)',fontsize=12)
plt.xlabel('log(array size)',fontsize=12)
Expand Down