M2process/Var_AF.m at master · HaoHuaqing/M2process · GitHub

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%% function 'Var_AF'
%
%   Calculate variance account for of NMF algorithm
%
%	Based on the criterion of Variance Accounted For (VAF)
%	VAF = 100 * ( 1 - ( ||M - D|| / ||M-M_mean|| ) );
%	From: Investigating reduction of dimensionality during single-joint elbow movements:a case study on muscle synergies
%	D:      approximated matrix D= W * H
%	EMG:	original matrix
%
%%

function VAF = Var_AF(EMG,Synergy)

M               =   EMG;
D               =   Synergy.D;
[row, column]	=	size(M);

Method          =   3;

switch Method
    case 1              % 'PDsynergy_VaF_mean_1.mat'
        M_mean          =	repmat(mean(M,1),[row 1]);
        VAF             =	100 * ( 1 - ( norm(M - D) / norm(M - M_mean) ) );

    case 2              % 'PDsynergy_VaF_mean_2.mat'
        M_mean          =	repmat(mean(M,2),[1 column]);
        VAF             =	100 * ( 1 - ( norm(M - D) / norm(M - M_mean) ) );

    case 3              % 'PDsynergy_VaF_square.mat'
        M_mean          =	repmat(mean(M,2),[1 column]);
        VAF             =	100 * ( 1 - ( norm(M - D)^2 / norm(M - M_mean)^2 ) );

    case 4              % 'PDsynergy_VaF_M.mat'
        VAF             =	100 * ( 1 - ( norm(M - D)^2 / norm(M)^2 ) );

end


end