Re: [boost] [GSoC] Some new ideas for this year's GSoC

Subject: Re: [boost] [GSoC] Some new ideas for this year's GSoC
From: Marshall Clow (mclow.lists_at_[hidden])
Date: 2010-04-07 15:24:38

On Apr 7, 2010, at 11:58 AM, Stefan wrote:

> Phil Endecott wrote:
>> Stefan wrote:
>>> * Optimize Boost String Algorithm finders to use an efficient substring matching algorithm as opposed to the naive algorithm. Most likely because of the fact that boost has implemented the finders for strings as generic algorithms, they haven't used efficient algorithms such as KMP, Boyer-Moore, Rabin-Karp etc.
>>>  \see boost/algorithm/string/detail/finder.hpp
>>>  The idea is to implement efficient algorithms such as the ones mentioned above to replace the current naive implementation. Note: it may be difficult to find nth matching substring position using some of these algorithms.
>>>  Difficulty: easy-medium
>>> 
>>> * Implement a string algorithm for generating the suffix array. The suffix array, after being precomputed on a certain string, allows for very efficient substring searches in the future. This is useful when the string doesn't change too often but there are plenty of substring to search against.
>> Hi Stefan,
>> Have you seen this thread, from a couple of years ago? :
>>    http://thread.gmane.org/gmane.comp.lib.boost.devel/171098
>> I don't know what has changed in string_algo since then, but I think there is probably plenty of opportunity for easy optimisation.
>> Do you have a motivating application for this?  A lot of this stuff is rather data-dependant, so having a particular application that can provide a benchmark is a good idea.  I guess that a suffix array library would be reasonable for a GSoC project, if you're good!  You might also like to consider variants that index at e.g. word boundaries; I have used something like that and it works well for some kinds of search.
>> Regards,  Phil.

I, for one, would like to see a lot more algorithms in Boost.
I have implemented B-M and B-M-H, but haven't polished them enough for submission.
[ Sometimes, if you squint correctly, I think I can make B-M-H (at least) work on bidirectional iterators as well as random-access once. ]

-- Marshall