You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: eig_geap.m
    path of file: ./repos/tensor_toolbox
    
    the code of the file until where you have to start completion: function [varargout] = eig_geap(A,B,varargin)
%EIG_GEAP Shifted power method for generalized tensor eigenproblem.
%
%   [LAMBDA,X] = EIG_GEAP(A,B) finds an eigenvalue (LAMBDA) and eigenve
    
function H = geap_hessian(data,alpha,dividebym)
%GEAP_HESSIAN Computes Generalized Tensor Eigenproblem gradient.
%
%   G = GEAP_HESSIAN(DATA) returns the GEAP function Hessian divided by
%   DATA.m, where DATA is the result of calling the GEAP_DATA function.
%
%   G = GEAP_FUNTION(DATA,ALPHA) returns the Hessian of the shifted GEAP
%   function, where the shift if ALPHA. 
%
%   G = GEAP_FUNCTION(DATA,ALPHA,FALSE) does not divide the result by
%   data.m.
%
%   See also GEAP_DATA, GEAP_FUNCTION, GEAP_GRADIENT, GEAP.

if ~exist('alpha','var')
    alpha = 0;
end