This project serves two purpose together.

1. It provides bindings for the LSH cpp code that was released by Andoni in Python. Original code is at www.mit.edu/~andoni/LSH. (Note: Since they released their code in GPL, therefore this is also GPL)

   The idea is that once everything compiles and all python paths are set correctly one would be able to do the following

    >>> import cylsh;
    >>> import numpy as np
    >>> db=cylsh.LSH(0.9,
                     0.9,
                     np.asarray([[.1, .7, .7],
                                [.11, .69, .7]]),
                     np.asarray([[.1, .7, .7]]),
                     1e6);
    >>> print db.query(np.asarray([.1, .7, 0]))
   

   "this example comes from the target example_cython_api" in the Makefile But remember that if you compiled it as cython_binding_mips then you must use the mips class.

2. Neyshabur et. al. (2014)[1] presented a clever modification to E2LSH to perform Maximum Inner Product Search. The code change was really small and it only needed like 10 lines of change to the following files to implement. So I added a flag to perform that as well in the Makefile.

   E2LSH-0.1/sources/Geometry.h
   E2LSH-0.1/sources/LocalitySensitiveHashing.h
   E2LSH-0.1/sources/LocalitySensitiveHashing.cpp
   E2LSH-0.1/sources/NearNeighbors.cpp
   

   Basically if you compile the module as "cython_binding_mips" then even though the API remains the same but the algorithm compiled would change and we would start doing MIPS based queries. Note that the parameter R would not map exactly to something meaningful.

Run the following in order to make the cython_bindings and to test them.

1. make cython_binding_mips for NeyShabur's Maximum Inner Product LSH, or make cython_binding_e2lsh for Euclidean distance LSH Note that MIPS and MIPS mean the same thing.

2. make test_cython_binding_mips or test_cython_binding_lsh

All the code needed for creating cython bindings is in sources_py. Read the original manual for understanding the c++ code. Read the diffs "git diff --name-only 0a490a0d0 HEAD" for the c++ and .h file to understand the changes done to implement Neyshabur et. al.'s algorithm

[1] @article{neyshabur2014alsh,
Title = {{On Symmetric and Asymmetric LSHs for Inner Product Search}},
Author = {{Neyshabur}, B. and {Srebro}, N.},
Journal = {ArXiv e-prints},
Month = oct,
Primaryclass = {stat.ML},
Year = 2014}