vbarre
#1
Hello,
I’m coding a program which implements the levenshtein distance between
two
strings. It works, but very slowly.
I discover that the slowest line in the code is:
current[j] = m
where current is an array of Fixnum, and m is a Fixnum.
If i comment this line the program runs about 50 times faster.
If I change it to any other thing, like “current[j] = 1” it still
running
fast.
I can’t understand why “current[j] = 1” is faster than “current[j] = m”.
Thanks,
Michel B.
vbarre
#2
Michel B. wrote:
I discover that the slowest line in the code is:
current[j] = m
where current is an array of Fixnum, and m is a Fixnum.
If i comment this line the program runs about 50 times faster.
If I change it to any other thing, like “current[j] = 1” it still
running
fast.
I can’t understand why “current[j] = 1” is faster than “current[j] = m”.
As far as I can tell, it is not faster.
n = 10_000_000
start_time = Time.now
intarr = [1, 2, 3]
n.times {intarr[1] = n}
p Time.now - start_time
start_time = Time.now
intarr = [1, 2, 3]
n.times {intarr[1] = 5}
p Time.now - start_time
result:
3.438
3.437
vbarre
#3
Opened http://ironruby.codeplex.com/WorkItem/View.aspx?WorkItemId=3314.
That’s wacky! Doesn’t happen if you remove the last or first item …
it’s gonna be fun to track that down. =)