On 1/30/2010 6:08 PM, elsa wrote:
Hello again,
Thanks for the tips r.e random.ranint(). This improved matters
somewhat, however my program is still too slow. If anyone has any
further tips on how to speed it up, they would be much appreciated!
So, I'm calling evolve(L,limit) from the interactive prompt. L is
initally [[100],['NA']]. Ideally limit would be 10^7.
Here is my program:
import random
n=100
def evolve(L,limit):
global n
while n<limit:
evnt = event()
if evnt!="None":
ind = chooseInd(L,n)
action(evnt,L,ind)
def chooseInd(L,n):
choiceSum=0
index=0
choice = random.randint(1,n)
while choiceSum< choice:
choiceSum+=L[index][0]
index +=1
return (index-1)
def event():
choice = random.random()
if choice<= .3:
event='b'
elif choice<= .4:
event ='d'
elif choice<= .5:
event = 'm'
else:
event = 'None'
return event
def action(event, L, index):
global n
if event == 'b':
L[index][0]+=1
n +=1
elif event == 'd':
L[index][0]-=1
n -=1
elif event == 'm':
L.append([1,index])
n +=1
thanks in advance,
Elsa.
Elsa,
1. You changed the subject line from "For loop searching takes too
long!" to "Still too slow". This causes newsreader programs to start a
new discussion thread, which makes life difficult for people who need to
refer back to previous messages. Please don't change the subject line
any more.
2. You provided a very clear description of your original question:
Now, what I need to do is randomly choose one myList[i], however the
distribution of my random choice needs to be proportional to the
values of myList[i][0].
This description should be the doc string for the chooseInd() function
-- for example:
def chooseInd(L,n):
"""
randomly choose one L[i], so that the distribution
of choices is proportional to the values of L[i][0]
"""
It is not clear (to me, anyway) what the other functions are trying to
accomplish. So please add a doc string to each of these functions, with
descriptions of similar clarity. This will help us a lot. And it will
help you, too, if you return to the code after a few days/weeks/months
of directing your attention elsewhere.
3. Please provide a *complete* transcript of an interactive session that
exercises this code.
Tx,
John
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