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Diffstat (limited to 'sourcecodes/bnt-master/netlab3.3/mdndist2.m')
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diff --git a/sourcecodes/bnt-master/netlab3.3/mdndist2.m b/sourcecodes/bnt-master/netlab3.3/mdndist2.m new file mode 100644 index 00000000..d7ed93d3 --- /dev/null +++ b/sourcecodes/bnt-master/netlab3.3/mdndist2.m @@ -0,0 +1,51 @@ +function n2 = mdndist2(mixparams, t) +%MDNDIST2 Calculates squared distance between centres of Gaussian kernels and data +% +% Description +% N2 = MDNDIST2(MIXPARAMS, T) takes takes the centres of the Gaussian +% contained in MIXPARAMS and the target data matrix, T, and computes +% the squared Euclidean distance between them. If T has M rows and N +% columns, then the CENTRES field in the MIXPARAMS structure should +% have M rows and N*MIXPARAMS.NCENTRES columns: the centres in each row +% relate to the corresponding row in T. The result has M rows and +% MIXPARAMS.NCENTRES columns. The I, Jth entry is the squared distance +% from the Ith row of X to the Jth centre in the Ith row of +% MIXPARAMS.CENTRES. +% +% See also +% MDNFWD, MDNPROB +% + +% Copyright (c) Ian T Nabney (1996-2001) +% David J Evans (1998) + +% Check arguments for consistency +errstring = consist(mixparams, 'mdnmixes'); +if ~isempty(errstring) + error(errstring); +end + +ncentres = mixparams.ncentres; +dim_target = mixparams.dim_target; +ntarget = size(t, 1); +if ntarget ~= size(mixparams.centres, 1) + error('Number of targets does not match number of mixtures') +end +if size(t, 2) ~= mixparams.dim_target + error('Target dimension does not match mixture dimension') +end + +% Build t that suits parameters, that is repeat t for each centre +t = kron(ones(1, ncentres), t); + +% Do subtraction and square +diff2 = (t - mixparams.centres).^2; + +% Reshape and sum each component +diff2 = reshape(diff2', dim_target, (ntarget*ncentres))'; +n2 = sum(diff2, 2); + +% Calculate the sum of distance, and reshape +% so that we have a distance for each centre per target +n2 = reshape(n2, ncentres, ntarget)'; + |
