// Copyright 2015 Singapore Management University (SMU). All Rights Reserved. // // Permission to use, copy, modify and distribute this software and // its documentation for purposes of research, teaching and general // academic pursuits, without fee and without a signed licensing // agreement, is hereby granted, provided that the above copyright // statement, this paragraph and the following paragraph on disclaimer // appear in all copies, modifications, and distributions. Contact // Singapore Management University, Intellectual Property Management // Office at [email protected], for commercial licensing opportunities. // // This software is provided by the copyright holder and creator "as is" // and any express or implied warranties, including, but not Limited to, // the implied warranties of merchantability and fitness for a particular // purpose are disclaimed. In no event shall SMU or the creator be // liable for any direct, indirect, incidental, special, exemplary or // consequential damages, however caused arising in any way out of the // use of this software. namespace TreeSVM module Kernel = let inline normCachedIJKernel kernel (cache: double [,]) i j = if i = j then 1.0 // as we do not use diagonal let's save there sqrt(Kii) else let i, j = if i < j then j, i else i, j let cachedValue = cache.[i, j] if cachedValue >= 0.0 then cachedValue else let inline getCachedSqrtKii i (cache: double [,]) = let cKii = cache.[i, i] if cKii >= 0.0 then cKii else let v = sqrt (kernel i i) cache.[i, i] <- v v let sqrtKii = getCachedSqrtKii i cache let sqrtKjj = getCachedSqrtKii j cache let kij = kernel i j let value = kij / (sqrtKii * sqrtKjj) cache.[i, j] <- value value let inline normKernel kernel x y = let kxx = kernel x x let kyy = kernel y y let kxy = kernel x y kxy / sqrt (kxx * kyy)