function D = solveLinearSystem(Model,K,P)
    % Partition system of equations
    %   [ Kff Kfs ] * [ Df ] = [ Pf ]
    %   [ Ksf Kss ]   [ Ds ] = [ Ps ]
    
    Kff = K(1:Model.neqf,1:Model.neqf);
    Pf  = P(1:Model.neqf);  %自由节点对应的自由度
    Ds  = zeros(Model.neqc,1);%被约束的自由度
    
    % Solve for Df
    Df = Kff\Pf;
    
    % Reconstruct the global unknown vector D
    D = [Df;Ds];
end