Hi Daniel, You are suggesting that current numpy arrays and implementation of a binary search can be used to create the functionality of an ordered map successfully, right? With this structure, trees for LSH forest can be built. Or we can go for a Cython implementation as well.
Gaël, What is the status of the evaluation of the cost to benefit ratio for this? I would appreciate it if we can decide on storing structure for the LSH implementation quickly as I have to make a sound plan for this project. [?] Best Regards, Maheshakya. On Tue, Mar 11, 2014 at 1:47 PM, Daniel Vainsencher < [email protected]> wrote: > My 0.02 cents; not a scikit learn contributor but have implemented this > before. > > First, its 138 citations on an important but simple datastructure/query > optimization: replace hashed maps with ordered maps for the range > queries, and use those to get the right number of candidates, instead of > too many or too few depending on local density. The problem of variable > density that it solves was pretty serious in my application, and seems > pretty generic. > > The main risk is in trying too hard to optimize the ordered map for > efficiency and compactness. A Judy array would probably be ideal, but > its C/C++ code with a patent in the background, and another B-Tree might > be a hassle as a dependency or maintenance. > > Fortunately, sorted arrays and binary search are already very efficient > ordered maps (as long as batched construction is acceptable), and > something more specialized can be swapped in later if justified. This > avoids the main risk completely for this GSOC at low cost. > > Other than that, the construction code is the same as in LSH, and the > query code is novel but well localized. Maybe test code for some of the > other NN search methods can be reused. > > Daniel Vainsencher > > On 03/11/2014 04:17 AM, Gael Varoquaux wrote: > > On Sun, Mar 09, 2014 at 08:46:32PM +1100, Robert Layton wrote: > >> That said, you'll need to make the case to the community -- the Forest > >> LSH is a variation of a key algorithm. LSH by itself is definitely > >> worthy of inclusion in scikit-learn, and it looks like Forest LSH would > >> be sufficiently well-used (Google tells me 138 citations), but I think > >> we need the community's decision. > > > > 138 citations on Google scholar isn't that much given the current > > standards of inclusion in scikit-learn. I have probably missed the > > discussion, but can someone make a compelling case for Forest LSH in a > > few lines and evaluate the cost to benefit ratio of implementing it > > (factoring in risk analysis and maintenance cost). > > > > Cheers, > > > > Gaël > > > > > ------------------------------------------------------------------------------ > > Learn Graph Databases - Download FREE O'Reilly Book > > "Graph Databases" is the definitive new guide to graph databases and > their > > applications. Written by three acclaimed leaders in the field, > > this first edition is now available. Download your free book today! > > http://p.sf.net/sfu/13534_NeoTech > > _______________________________________________ > > Scikit-learn-general mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/scikit-learn-general > > > > > > ------------------------------------------------------------------------------ > Learn Graph Databases - Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and their > applications. Written by three acclaimed leaders in the field, > this first edition is now available. Download your free book today! > http://p.sf.net/sfu/13534_NeoTech > _______________________________________________ > Scikit-learn-general mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/scikit-learn-general > -- Undergraduate, Department of Computer Science and Engineering, Faculty of Engineering. University of Moratuwa, Sri Lanka
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