Re: Entering a very large number

On Fri, Mar 30, 2018 at 9:30 PM, bartc wrote: > On 26/03/2018 16:31, Chris Angelico wrote: >> Yeah. It's so annoying that compilers work so hard to make your code >> fast, when all you want to do is measure exactly how slow it is. >> Compiler authors are stupid. > > > In some

Re: Entering a very large number

On 3/30/18 6:41 AM, bartc wrote: On 27/03/2018 04:49, Richard Damon wrote: On 3/26/18 8:46 AM, bartc wrote: Hence my testing with CPython 3.6, rather than on something like PyPy which can give results that are meaningless. Because, for example, real code doesn't repeatedly execute the same

Re: Entering a very large number

On 27/03/2018 04:49, Richard Damon wrote: On 3/26/18 8:46 AM, bartc wrote: Hence my testing with CPython 3.6, rather than on something like PyPy which can give results that are meaningless. Because, for example, real code doesn't repeatedly execute the same pointless fragment millions of

Re: Entering a very large number

On 26/03/2018 16:31, Chris Angelico wrote: On Mon, Mar 26, 2018 at 11:46 PM, bartc wrote: On 26/03/2018 13:30, Richard Damon wrote: On 3/26/18 6:31 AM, bartc wrote: The purpose was to establish how such int("...") conversions compare in overheads with actual arithmetic

Re: Entering a very large number

On Mon, 26 Mar 2018 23:49:07 -0400, Richard Damon wrote: > The bigger issue is that these sort of micro-measurements aren't > actually that good at measuring real quantitative performance costs. > They can often give qualitative indications, but the way modern > computers work, processing

Re: Entering a very large number

On 3/26/18 8:46 AM, bartc wrote: On 26/03/2018 13:30, Richard Damon wrote: On 3/26/18 6:31 AM, bartc wrote: The purpose was to establish how such int("...") conversions compare in overheads with actual arithmetic with the resulting numbers. Of course if this was done in C with a version

Re: Entering a very large number

Am 26.03.18 um 12:31 schrieb bartc: On 26/03/2018 10:34, Steven D'Aprano wrote: So what exactly did you do? I did this: def fn():     C = int(     "28871482380507712126714295971303939919776094592797"     "22700926516024197432303799152733116328983144639225"    

Re: Entering a very large number

On Mon, Mar 26, 2018 at 11:46 PM, bartc wrote: > On 26/03/2018 13:30, Richard Damon wrote: >> >> On 3/26/18 6:31 AM, bartc wrote: > > >>> The purpose was to establish how such int("...") conversions compare in >>> overheads with actual arithmetic with the resulting numbers. >>>

Re: Entering a very large number

Steven D'Aprano writes: > On Mon, 26 Mar 2018 02:37:44 +0100, bartc wrote: > >> If I instead initialise C using 'C = int("288712...")', then timings >> increase as follows: > > Given that the original number given had 397 digits and has a bit length > of

Re: Entering a very large number

On 26/03/2018 13:30, Richard Damon wrote: On 3/26/18 6:31 AM, bartc wrote: The purpose was to establish how such int("...") conversions compare in overheads with actual arithmetic with the resulting numbers. Of course if this was done in C with a version that had builtin bignum ints or an

Re: Entering a very large number

On Mon, 26 Mar 2018 11:45:33 +0100, bartc wrote: > Similar overheads occur when you use string=>int even on small numbers: > > This code: > > C = int("12345") > D = C+C # or C*C; about the same results > > takes 5 times as long (using my CPython 3.6.x on Windows) as: > > C

Re: Entering a very large number

On 3/26/18 6:31 AM, bartc wrote: On 26/03/2018 10:34, Steven D'Aprano wrote: On Mon, 26 Mar 2018 02:37:44 +0100, bartc wrote: If I instead initialise C using 'C = int("288712...")', then timings increase as follows: Given that the original number given had 397 digits and has a bit length

Re: Entering a very large number

On 3/26/18 6:45 AM, bartc wrote: On 26/03/2018 03:35, Richard Damon wrote: On 3/25/18 9:37 PM, bartc wrote: So the overhead /can/ be substantial, and /can/ be significant compared with doing bignum calculations. Of course, once initialised, C might be used a hundred times, then the

Re: Entering a very large number

On Mon, 26 Mar 2018 11:31:22 +0100, bartc wrote: > On 26/03/2018 10:34, Steven D'Aprano wrote: >> So what exactly did you do? > > I'm not sure why you think the language C came into it. My misunderstanding. Sorry. -- Steve -- https://mail.python.org/mailman/listinfo/python-list

Re: Entering a very large number

On 26/03/2018 03:35, Richard Damon wrote: On 3/25/18 9:37 PM, bartc wrote: So the overhead /can/ be substantial, and /can/ be significant compared with doing bignum calculations. Of course, once initialised, C might be used a hundred times, then the overhead is less significant. But it is

Re: Entering a very large number

On 26/03/2018 10:34, Steven D'Aprano wrote: On Mon, 26 Mar 2018 02:37:44 +0100, bartc wrote: If I instead initialise C using 'C = int("288712...")', then timings increase as follows: Given that the original number given had 397 digits and has a bit length of 1318, I must admit to some

Re: Entering a very large number

On Mon, 26 Mar 2018 02:37:44 +0100, bartc wrote: > Calling a function that sets up C using 'C = 288714...' on one line, and > that then calculates D=C+C, takes 0.12 seconds to call 100 times. > > To do D=C*C, takes 2.2 seconds (I've subtracted the function call > overhead of 0.25 seconds;

Re: Entering a very large number

On Monday, March 26, 2018 at 12:55:43 AM UTC+5:30, Peter J. Holzer wrote: > On 2018-03-25 19:18:23 +0200, ast wrote: > > Le 25/03/2018 à 03:47, Steven D'Aprano a écrit : > > > The Original Poster (OP) is concerned about saving, what, a tenth of a > > > microsecond in total? Hardly seems worth the

Re: Entering a very large number

On 3/25/18 9:37 PM, bartc wrote: On 26/03/2018 00:27, Richard Damon wrote: On 3/25/18 8:32 AM, bartc wrote: Using CPython on my machine, doing a string to int conversion that specific number took 200 times as long as doing a normal assignment. That conversion took 4 microseconds. Not

Re: Entering a very large number

On 26/03/2018 00:27, Richard Damon wrote: On 3/25/18 8:32 AM, bartc wrote: Using CPython on my machine, doing a string to int conversion that specific number took 200 times as long as doing a normal assignment. That conversion took 4 microseconds. Not significant if it's only done once.

Re: Entering a very large number

On 3/25/18 8:32 AM, bartc wrote: On 25/03/2018 02:47, Steven D'Aprano wrote: On Sun, 25 Mar 2018 00:05:56 +0100, Peter J. Holzer wrote: [...] yes, good idea Not if you want to avoid that string to int conversion (as you stated). That is still there, but in addition you now split the string

Re: Entering a very large number

On 2018-03-25 19:18:23 +0200, ast wrote: > Le 25/03/2018 à 03:47, Steven D'Aprano a écrit : > > The Original Poster (OP) is concerned about saving, what, a tenth of a > > microsecond in total? Hardly seems worth the effort, especially if you're > > going to end up with something even slower. > >

Re: Entering a very large number

Le 25/03/2018 à 03:47, Steven D'Aprano a écrit : On Sun, 25 Mar 2018 00:05:56 +0100, Peter J. Holzer wrote: The Original Poster (OP) is concerned about saving, what, a tenth of a microsecond in total? Hardly seems worth the effort, especially if you're going to end up with something even

Re: Entering a very large number

On 25/03/2018 16:47, Grant Edwards wrote: On 2018-03-25, bartc wrote: On 25/03/2018 02:47, Steven D'Aprano wrote: The Original Poster (OP) is concerned about saving, what, a tenth of a microsecond in total? Hardly seems worth the effort, especially if you're going to end up

Re: Entering a very large number

bartc writes: > On 25/03/2018 15:53, Joe Pfeiffer wrote: >> ast writes: > >>> C = int( >>> "28871482380507712126714295971303939919776094592797" >>> "22700926516024197432303799152733116328983144639225" >>> "94197780311092934965557841894944174093380561511397" >>>

Re: Entering a very large number

On 2018-03-25, bartc wrote: > On 25/03/2018 02:47, Steven D'Aprano wrote: > >> The Original Poster (OP) is concerned about saving, what, a tenth of a >> microsecond in total? Hardly seems worth the effort, especially if you're >> going to end up with something even slower. > >

Re: Entering a very large number

On 25/03/2018 15:53, Joe Pfeiffer wrote: ast writes: C = int( "28871482380507712126714295971303939919776094592797" "22700926516024197432303799152733116328983144639225" "94197780311092934965557841894944174093380561511397" "4215424169339729054237110027510420801349667317"

Re: Entering a very large number

On 3/25/2018 10:53 AM, Joe Pfeiffer wrote: After following the thread for a while... you will, of course, simply have to do a string to int conversion no matter what approach you take to writing it. The number is a string of digits; it has to be converted to the internal representation. Even

Re: Entering a very large number

On 25/03/2018 15:01, Christian Gollwitzer wrote: Am 25.03.18 um 14:32 schrieb bartc: Using CPython on my machine, doing a string to int conversion that specific number took 200 times as long as doing a normal assignment. That conversion took 4 microseconds. Not significant if it's only done

Re: Entering a very large number

ast writes: > Hi > > I found this way to put a large number in > a variable. > > C = int( > "28871482380507712126714295971303939919776094592797" > "22700926516024197432303799152733116328983144639225" > "94197780311092934965557841894944174093380561511397" >

Re: Entering a very large number

Am 25.03.18 um 14:32 schrieb bartc: Using CPython on my machine, doing a string to int conversion that specific number took 200 times as long as doing a normal assignment. That conversion took 4 microseconds. Not significant if it's only done once. But it might be executed a million times.

Re: Entering a very large number

On 25/03/2018 02:47, Steven D'Aprano wrote: On Sun, 25 Mar 2018 00:05:56 +0100, Peter J. Holzer wrote: [...] yes, good idea Not if you want to avoid that string to int conversion (as you stated). That is still there, but in addition you now split the string into a list and then join the

Re: Entering a very large number

On Sun, 25 Mar 2018 00:05:56 +0100, Peter J. Holzer wrote: [...] >> yes, good idea > > Not if you want to avoid that string to int conversion (as you stated). > > That is still there, but in addition you now split the string into a > list and then join the list into a different string. I'm

Re: Entering a very large number

On 2018-03-23 14:12:27 +0100, ast wrote: > Le 23/03/2018 à 13:55, Wolfgang Maier a écrit : > > On 03/23/2018 01:30 PM, Wolfgang Maier wrote: > > > On 03/23/2018 01:16 PM, ast wrote: [quoted from the first mail in this thread:] > > > > It works but is it not optimal since there is a > > > > string

Re: Entering a very large number

On 2018-03-23 14:01, ast wrote: > Le 23/03/2018 à 13:43, Rustom Mody a écrit : >> On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: >>> Hi >>> >>> I found this way to put a large number in >>> a variable. >> >> What stops you from entering the number on one single (v long) line? > > >

Re: Entering a very large number

On 3/23/18 9:35 AM, ast wrote: Le 23/03/2018 à 14:16, Antoon Pardon a écrit : On 23-03-18 14:01, ast wrote: Le 23/03/2018 à 13:43, Rustom Mody a écrit : On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: What meaningful information from number can you easily retrieve from

Re: Entering a very large number

On 23-03-18 14:35, ast wrote: > Le 23/03/2018 à 14:16, Antoon Pardon a écrit : >> On 23-03-18 14:01, ast wrote: >>> Le 23/03/2018 à 13:43, Rustom Mody a écrit : On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: > > >> What meaningful information from number can you easily retrieve

Re: Entering a very large number

Le 23/03/2018 à 14:16, Antoon Pardon a écrit : On 23-03-18 14:01, ast wrote: Le 23/03/2018 à 13:43, Rustom Mody a écrit : On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: What meaningful information from number can you easily retrieve from representing the number in some kind

Re: Entering a very large number

Le 23/03/2018 à 13:55, Wolfgang Maier a écrit : On 03/23/2018 01:30 PM, Wolfgang Maier wrote: On 03/23/2018 01:16 PM, ast wrote: n = int(     ''.join(""" 37107287533902102798797998220837590246510135740250 46376937677490009712648124896970078050417018260538

Re: Entering a very large number

On 23-03-18 14:01, ast wrote: > Le 23/03/2018 à 13:43, Rustom Mody a écrit : >> On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: >>> Hi >>> >>> I found this way to put a large number in >>> a variable. >> >> What stops you from entering the number on one single (v long) line? > > > It

Re: Entering a very large number

On 23.03.2018 14:01, ast wrote: > It is not beautiful and not very readable. It is better to > have a fixed number of digits per line (eg 50) Oh yes, because clearly a 400-digit number becomes VERY beautiful and readable once you add line breaks to it. Cheers, Joe -- >> Wo hattest Du das

Re: Entering a very large number

Le 23/03/2018 à 13:30, Wolfgang Maier a écrit : On 03/23/2018 01:16 PM, ast wrote: A very simple improvement would be to use a single triple-quoted string. Assuming you are copy/pasting the number from somewhere that will save a lot of your time. no, it seems that sone \n are inserted

Re: Entering a very large number

Le 23/03/2018 à 13:43, Rustom Mody a écrit : On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: Hi I found this way to put a large number in a variable. What stops you from entering the number on one single (v long) line? It is not beautiful and not very readable. It is better

Re: Entering a very large number

On 03/23/2018 01:30 PM, Wolfgang Maier wrote: On 03/23/2018 01:16 PM, ast wrote: Hi I found this way to put a large number in a variable. C = int( "28871482380507712126714295971303939919776094592797" "22700926516024197432303799152733116328983144639225"

Re: Entering a very large number

On Friday, March 23, 2018 at 5:46:56 PM UTC+5:30, ast wrote: > Hi > > I found this way to put a large number in > a variable. What stops you from entering the number on one single (v long) line? In case there is a religious commitment to PEP 8 dicta, the recommended meditation is this line

Re: Entering a very large number

On 03/23/2018 01:16 PM, ast wrote: Hi I found this way to put a large number in a variable. C = int( "28871482380507712126714295971303939919776094592797" "22700926516024197432303799152733116328983144639225" "94197780311092934965557841894944174093380561511397"

Entering a very large number

Hi I found this way to put a large number in a variable. C = int( "28871482380507712126714295971303939919776094592797" "22700926516024197432303799152733116328983144639225" "94197780311092934965557841894944174093380561511397" "4215424169339729054237110027510420801349667317"