4 ms·

jacques, I'll try to get everything. I didn't benchmark the 2 examples since they run about 8 hours each. I mentioned the next JVM release, only to highlight

by lbj 17y ago

jacques, I'll try to get everything. I didn't benchmark the 2 examples since they run about 8 hours each. I mentioned the next JVM release, only to highlight that some improvements are being implemented for BigInteger, which currently is a slow as can be. Regarding the 2.nd example and linecounting. Firstly, if I counted blank lines with Python I apologize, I must have been a bit too fast going over it. Generally the line counting was not meant to be viewed as THE indicator for quality, as I obviously compressed the Clojure-code more than what was optimally - The irony didn't come across though. Your speed on the webcrawler is really quite amazing. I hit it at 2200 here, which is around 4 o'clock on the east coast of the US if I'm not mistaking, using my 4Mbit line. It took exactly 1 hour and 53 minutes, so if yours run in 6 minutes ... Something was horribly wrong. The fact that my gain is from opening several connections is not masked in anyway - I knew that was the key to speed, that's why I did it :) Anyway, putting line counting aside I suggest focus be given to the clarity and expressiveness of the samples - where Python is not lacking. Line counting is fun for golfing. /Lau ps: Out of curiosity, did you get 8200+ something tasks from your crawl?

jacquesm 17y ago
> I didn't benchmark the 2 examples since they run about 8 hours each. ok. > I mentioned the next JVM release, only to highlight that some improvements are being implemented for BigInteger, which currently is a slow as can be. Ok, Afaik BigIntegers are slow everywhere. > Regarding the 2.nd example and linecounting. Firstly, if I counted blank lines with Python I apologize, I must have been a bit too fast going over it. ok > Generally the line counting was not meant to be viewed as THE indicator for quality, as I obviously compressed the Clojure-code more than what was optimally - The irony didn't come across though. It didn't, besides that, it degrades the whole of your post to focussing on meaningless metrics. > Your speed on the webcrawler is really quite amazing. I hit it at 2200 here, which is around 4 o'clock on the east coast of the US if I'm not mistaking, using my 4Mbit line. It took exactly 1 hour and 53 minutes, so if yours run in 6 minutes ... Something was horribly wrong. That was my take on it. When I saw how fast it did the first couple I decided to time it, I was quite surprised on seeing the results. Now I'm curious how fast clojure would run on this rig. fwiw it wasn't exactly doing nothing while running that test either, I just didn't feel like shutting stuff down. > The fact that my gain is from opening several connections is not masked in anyway - I knew that was the key to speed, that's why I did it :) And you're still twice as slow as my python run. I think that benchmarking anything in a context such as networking should be done by several runs at different times of day and presenting both the average as well as the min and max run times. > Anyway, putting line counting aside I suggest focus be given to the clarity and expressiveness of the samples - where Python is not lacking. Line counting is fun for golfing. I think that expressiveness in both languages is comparable, I don't really see a clear winner, it depends on the use case. I'm more used to imperative languages (for the moment) so I can read the python code a little easier but I've long ago learned that micro-optimizing the number of lines at the expense of clarity is a losing strategy. > Out of curiosity, did you get 8200+ something tasks from your crawl? here's the condensed output: eleven:/tmp# date ; python examples.py Mon Oct 19 16:49:35 EDT 2009 100 doors: 50 examples. 99 Bottles of Beer: 67 examples. Abstract type: 18 examples. Ackermann Function: 56 examples. Active object: 8 examples. Adding variables to a class instance at runtime: 16 examples. Address Operations: 18 examples. ... XML Creation: 17 examples. XML Reading: 17 examples. XML and XPath: 15 examples. Xiaolin Wu's line algorithm: 3 examples. Y combinator: 20 examples. Yuletide Holiday: 30 examples. Zig Zag: 27 examples. Total: 8275 examples. eleven:/tmp# date Mon Oct 19 16:55:22 EDT 2009 eleven:/tmp# --- edit: I just saw jcl's post above, combining his trick with some more cramming we now have: from math import sqrt def is_prime(i): return (i > 1 and all(i % x != 0 for x in range(2, int(sqrt(i)) + 1))) def is_mersenne_prime ( p ): if p == 2: return True m_p = ( 1 << p ) - 1; s = 4; for i in range(3, p+1): s = (s ** 2 - 2) % m_p return s == 0 for p in range(2, 33219): if is_prime(p) and is_mersenne_prime(p): print("M%d"%p); There must be a way to make it shorter still ;)
- daivd 17y ago
  Making it shorter is trivial :) I have never tried posting code here, so I I'll try to get the formatting right. #The import line is unnecessary. It can be inlined, like so: def is_prime(i): return (i > 1 and all(i % x != 0 for x in range(2, int(__import__('math').sqrt(i)) + 1))) #Mersenne prime can be put on one line with some functional beautification: def is_mersenne_prime(p): return p == 2 or not reduce(lambda x, y: (x ** 2 - 2) % (( 1 << p ) - 1), range(3, p + 1), 4) #With a list comprehension we do not need "if ..:" and can put the loop on one line as well: for p in [range(2,33219) if s_prime(p) and is_mersenne_prime(p)]: print("M%d"%p) Three lines. Of course the functions are unnecessary, so inline them in the for-loop and we have our magic target, one line! I have replaced the list comprehension and range with generators, so if you run this one-liner in your python terminal you will get a continuous stream of primes (if it flushes the prints properly). for q in (p for p in xrange(2,33219) if (p > 1 and all(p % x != 0 for x in range(2, int(__import__('math').sqrt(p)) + 1))) and (p == 2 or not reduce(lambda x, y: (x ** 2 -2) % (( 1 << p ) - 1), range(3, p + 1), 4))): print("M%d"%q) Easy as pie. I don't know anything about code golf, so perhaps I am breaking some rule with the longer than 80 char line? Using ; to sequence statements as in the original is definitely cheating, IMHO :)

by lbj 17y ago

jacquesm 17y ago

> I didn't benchmark the 2 examples since they run about 8 hours each. ok. > I mentioned the next JVM release, only to highlight that some improvements are being implemented for BigInteger, which currently is a slow as can be. Ok, Afaik BigIntegers are slow everywhere. > Regarding the 2.nd example and linecounting. Firstly, if I counted blank lines with Python I apologize, I must have been a bit too fast going over it. ok > Generally the line counting was not meant to be viewed as THE indicator for quality, as I obviously compressed the Clojure-code more than what was optimally - The irony didn't come across though. It didn't, besides that, it degrades the whole of your post to focussing on meaningless metrics. > Your speed on the webcrawler is really quite amazing. I hit it at 2200 here, which is around 4 o'clock on the east coast of the US if I'm not mistaking, using my 4Mbit line. It took exactly 1 hour and 53 minutes, so if yours run in 6 minutes ... Something was horribly wrong. That was my take on it. When I saw how fast it did the first couple I decided to time it, I was quite surprised on seeing the results. Now I'm curious how fast clojure would run on this rig. fwiw it wasn't exactly doing nothing while running that test either, I just didn't feel like shutting stuff down. > The fact that my gain is from opening several connections is not masked in anyway - I knew that was the key to speed, that's why I did it :) And you're still twice as slow as my python run. I think that benchmarking anything in a context such as networking should be done by several runs at different times of day and presenting both the average as well as the min and max run times. > Anyway, putting line counting aside I suggest focus be given to the clarity and expressiveness of the samples - where Python is not lacking. Line counting is fun for golfing. I think that expressiveness in both languages is comparable, I don't really see a clear winner, it depends on the use case. I'm more used to imperative languages (for the moment) so I can read the python code a little easier but I've long ago learned that micro-optimizing the number of lines at the expense of clarity is a losing strategy. > Out of curiosity, did you get 8200+ something tasks from your crawl? here's the condensed output: eleven:/tmp# date ; python examples.py Mon Oct 19 16:49:35 EDT 2009 100 doors: 50 examples. 99 Bottles of Beer: 67 examples. Abstract type: 18 examples. Ackermann Function: 56 examples. Active object: 8 examples. Adding variables to a class instance at runtime: 16 examples. Address Operations: 18 examples. ... XML Creation: 17 examples. XML Reading: 17 examples. XML and XPath: 15 examples. Xiaolin Wu's line algorithm: 3 examples. Y combinator: 20 examples. Yuletide Holiday: 30 examples. Zig Zag: 27 examples. Total: 8275 examples. eleven:/tmp# date Mon Oct 19 16:55:22 EDT 2009 eleven:/tmp# --- edit: I just saw jcl's post above, combining his trick with some more cramming we now have: from math import sqrt def is_prime(i): return (i > 1 and all(i % x != 0 for x in range(2, int(sqrt(i)) + 1))) def is_mersenne_prime ( p ): if p == 2: return True m_p = ( 1 << p ) - 1; s = 4; for i in range(3, p+1): s = (s ** 2 - 2) % m_p return s == 0 for p in range(2, 33219): if is_prime(p) and is_mersenne_prime(p): print("M%d"%p); There must be a way to make it shorter still ;)

daivd 17y ago
Making it shorter is trivial :) I have never tried posting code here, so I I'll try to get the formatting right. #The import line is unnecessary. It can be inlined, like so: def is_prime(i): return (i > 1 and all(i % x != 0 for x in range(2, int(__import__('math').sqrt(i)) + 1))) #Mersenne prime can be put on one line with some functional beautification: def is_mersenne_prime(p): return p == 2 or not reduce(lambda x, y: (x ** 2 - 2) % (( 1 << p ) - 1), range(3, p + 1), 4) #With a list comprehension we do not need "if ..:" and can put the loop on one line as well: for p in [range(2,33219) if s_prime(p) and is_mersenne_prime(p)]: print("M%d"%p) Three lines. Of course the functions are unnecessary, so inline them in the for-loop and we have our magic target, one line! I have replaced the list comprehension and range with generators, so if you run this one-liner in your python terminal you will get a continuous stream of primes (if it flushes the prints properly). for q in (p for p in xrange(2,33219) if (p > 1 and all(p % x != 0 for x in range(2, int(__import__('math').sqrt(p)) + 1))) and (p == 2 or not reduce(lambda x, y: (x ** 2 -2) % (( 1 << p ) - 1), range(3, p + 1), 4))): print("M%d"%q) Easy as pie. I don't know anything about code golf, so perhaps I am breaking some rule with the longer than 80 char line? Using ; to sequence statements as in the original is definitely cheating, IMHO :)