Hmmm, I don't know though, usually the usage pattern with hashed collections has been to presize explicitly and then add to them... what kind of use cases are you dealing with?
Henrik Johansen wrote: > Having spent a fair deal of time (in VisualWorks) worrying about my > intial Set sizes, writing functions to precompute sane sizes for > arbitrary inputs and adding changeCapacityTo: calls before addAll: > operations due to performance issues on a case-by-case basis (Squeak/ > Pharo doesn't even HAVE a changeCapacityTo: ), I have to strongly > disagree. > > I'd rather spend my time thinking about my problem domain, and know > the Set implementation handles the nitty-gritty details in a > sufficiently smart way. > > Whether that means growing once to accomedate the worst case, then > shrinking afterwards, or doing a grow check every X added items, in > the unlikely event that what you're adding is a 3 million element > Array with 10 unique objects, I don't really care. > > Cheers, > Henry > > On Jul 2, 2009, at 7:38 10AM, Andres Valloud wrote: > > >> (Set new: desiredCapacity) addAll: "consecutive integers" >> >> may be a better compromise. >> >> Andres. >> >> >> Stéphane Ducasse wrote: >> >>> Thanks this is really good. >>> We will probably integrate these changes really fast >>> >>> On Jul 1, 2009, at 1:03 PM, Henrik Johansen wrote: >>> >>> >>> >>>> I took some time to check this yesterday, my comments on the code >>>> itself are basically the same as what Lucas posted in the issue >>>> tracker. >>>> Works as advertised, but should probably clean out the "gunk" >>>> which is >>>> unused after it's integrated. >>>> >>>> Some feedback on possible improvements: >>>> - What it does, is basically speed up the adds to the new array in a >>>> grow that might happen Why not take this all to the logical >>>> conclusion, and instead optimize an addAll: method to be used in >>>> grow, >>>> that assumes elements are not in set (and themselves are not >>>> duplicates)? F.ex. it could also add to tally just once, instead of >>>> one increase per element as the noCompareAdd: does. (an add method >>>> with no tally add, no = object check, and no growCheck). >>>> >>>> - The usual addAll: method can be sped up in a similar way, by >>>> performing one grow operation before adding elements if necessary >>>> (pessimistically assuming all elements are unique), then use an add >>>> method which does not check for grow need at all. (an add method >>>> with >>>> tally add and = object check, but no growCheck) >>>> If desirable, you could also shrink the capacity after adds are >>>> done, to match the real amount of new elements. >>>> >>>> Adding (1 to: 1200000) to a new Set with such an addAll: method took >>>> 1/2 to 1/3rd the time of the regular addAll: method, even with the >>>> lower grow cost of FasterSets. (Lower gains if Set is presized, >>>> and if >>>> hash-calculation is bigger part of cost) >>>> >>>> Note: If you want to stay ANSI-compatible, one tricky point in >>>> such an >>>> optimization is adding all objects in collection up to a nil >>>> element, >>>> then raising an error. (ie: must produce equivalent results to add: >>>> performed of each of collections elements in sequence ) >>>> >>>> Cheers, >>>> Henry >>>> >>>> >>>> On Jun 25, 2009, at 8:55 03PM, Stéphane Ducasse wrote: >>>> >>>> >>>> >>>>> I would really like to assess FasterSets for Pharo1.1 >>>>> >>>>> Begin forwarded message: >>>>> >>>>> >>>>> >>>>>> From: Ralph Boland <[email protected]> >>>>>> Date: June 25, 2009 8:30:13 PM CEDT >>>>>> To: Stéphane Ducasse <[email protected]> >>>>>> Subject: Re: about fasterTests >>>>>> >>>>>> 2009/6/25 Stéphane Ducasse <[email protected]>: >>>>>> >>>>>> >>>>>>> we are interest to get better libraries in pharo. >>>>>>> If you want to join and help making sure that your code in >>>>>>> integrated in >>>>>>> pharo1.1 >>>>>>> please say it and may be join the pharo mailing-list. >>>>>>> >>>>>>> Stef >>>>>>> >>>>>>> >>>>>>> >>>>>> Yes, I would like my code 'FasterSets' added to Pharo. >>>>>> I joined the pharo mailing list. >>>>>> Today I will mail you my MIT license release. >>>>>> Probably will take a couple of weeks (From Calgary, Canada) to get >>>>>> there. >>>>>> Once I am added as a contributer I will release my code to Pharo >>>>>> for >>>>>> verification. >>>>>> In the meantime if any Squeakers try out my code and report bugs I >>>>>> will fix them >>>>>> before releasing to Pharo. >>>>>> >>>>>> Some comments: >>>>>> >>>>>> 1) Since FasterSets modifies low level methods in class Set and >>>>>> its >>>>>> subclasses it >>>>>> may be incompatible with packages that create subclasses of Set >>>>>> and then >>>>>> override low level methods. If someone could send me a list of >>>>>> package add-ons >>>>>> to Pharo that do this then I can download them and make any >>>>>> modifications >>>>>> necessary for them to run with FasterSets and make these changes >>>>>> part of my >>>>>> release. Note that it is no more difficult to subclass from Set >>>>>> with FasterSets >>>>>> than without; it is just different and only different if you do >>>>>> low level things. >>>>>> >>>>>> 2) FasterSets uses a method 'noCompareOrGrowAdd:' which adds >>>>>> an element to a set without doing compares or growing the set. >>>>>> Needless to say it is a private method. >>>>>> I also have a public method 'nastyAddNew:' which, like >>>>>> 'noCompareOrGrowAdd:' adds an element to a set without checking >>>>>> if the >>>>>> element is already there but does do a grow if needed. >>>>>> This is useful (i.e. faster) in situations where you KNOW the >>>>>> object >>>>>> you are adding to a set is not there already. >>>>>> However if the object IS already there then you now have two >>>>>> of them in your set; i.e. you now have a subtle bug. >>>>>> I use 'nastyAddNew:' in my code but never made it a part of >>>>>> FasterSets >>>>>> because it is questionable whether or not such a method should be >>>>>> available generally. However, if I can decide I like the >>>>>> 'nastyAddNew:' >>>>>> method and am willing to use it despite its risks so can others >>>>>> so there >>>>>> is an argument for it being added. >>>>>> While my expectation is that you don't want 'nastyAddNew:' in >>>>>> Pharo >>>>>> I thought you should at least be aware of it. >>>>>> >>>>>> Regards, >>>>>> >>>>>> Ralph Boland >>>>>> >>>>>> >>>>> _______________________________________________ >>>>> Pharo-project mailing list >>>>> [email protected] >>>>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >>>>> >>>>> >>>>> >>>> _______________________________________________ >>>> Pharo-project mailing list >>>> [email protected] >>>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >>>> >>>> >>> _______________________________________________ >>> Pharo-project mailing list >>> [email protected] >>> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >>> . >>> >>> >>> >> _______________________________________________ >> Pharo-project mailing list >> [email protected] >> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >> >> > > . > > _______________________________________________ Pharo-project mailing list [email protected] http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
