Question

care to comment on this code for problem 4?

Answer 1

def findMaxExpenses(salary,save,preRetireGrowthRates,postRetireGrowthRates,epsilon):

preretirement=nestEggVariable(salary,save,preRetireGrowthRates)
index=len(preRetireGrowthRates)-1
startmoney=preretirement[index]
low=0
high=startmoney
counter=1
guess=startmoney/2.0
while guess<startmoney and counter<100:
expenses=guess
post_Retirement=postRetirement(startmoney,postRetireGrowthRates,expenses)
index2=len(postRetireGrowthRates)-1
endmoney=post_Retirement[index2]
if endmoney<epsilon:
high=guess
else:
low=guess
guess=(low+high)/2.0
counter+=1
print expenses, endmoney,counter

if endmoney<epsilon and endmoney>-epsilon:
break




def nestEggVariable(salary, save, growthRates):
cashpile=[]
money=0
counter=0
for counter in range (0,len(growthRates)):
money=money+(0.01 * growthRates[counter]) * money+(salary *(.01 *save))

cashpile.append(money)

return cashpile

def postRetirement(savings, growthRates, expenses):

cashpile=[]
money=savings
counter=0
for counter in range (0,len(growthRates)):
money=money+(0.01 * growthRates[counter]) * money-expenses
cashpile.append(money)

return cashpile


def testFindMaxExpenses():
salary = 10000
save = 10
preRetireGrowthRates = [3, 4, 5, 0, 3]
postRetireGrowthRates = [10, 5, 0, 5, 1]
epsilon = .01
expenses = findMaxExpenses(salary, save, preRetireGrowthRates,
postRetireGrowthRates, epsilon)
print expenses
# Output should have a value close to:
# 1229.95548986

Answer 2

pls use pastebin or dpaste.com to post code.

does it work?? were you looking for style or implementation comments?

Answer 3

It finds the answer in 20 iterations. I had a bit of a problem deciding how to make the program stop running. I made a condition that stopped the counter if the ending balance was between epsilon and -epsilon. My question is if epsilon wasn't .01 this wouldn't work as well, is there a better way to make an end condition?

Answer 4

Don;t think so.. You have to decide how precise you want your answer to be - the more precise, the more iterations. I imagine since the problem concerns money, you could round everything to cents, multiply by one-hundred and work in integers but that is sorta the same thing.

Answer 5

You really will need to use a code host, github, dpaste, something like that, to put up that much code. Then people can easily grab a copy, put in some print statements and play around with your script a bit.