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: dss_create_state.m
    path of file: ./repos/fieldtrip/external/dss
    
    the code of the file until where you have to start completion: function state = dss_create_state(X_or_state, parameters)
% Initializes DSS state structure based on existing state
% and given parameters.
%   state = dss_create_state(X or state, parameters)
%     X           Mixed source, matrix with row vectors as signals.
%     state       New or updated persistent algorithm state structure
%     parameters  Optional parameters that are included in the state.
%                 Overwrites parameters in the state variable.
%
% Description of parameter and state variables:
%   algorithm       DSS algorithm
%                     'defl' = Deflation approach (default)
%		      'symm' = Symmetric approach 
%		      'pca'  = Linear PCA DSS
%   sdim            Number of components to be extracted
%   wdim            Dimension of the data after whitening (preprocessing)
%   verbose         Verbosity
%                     0 = no print output
%                     1 = terse print output (default)
%                     2 = more detailed print output 
%                     3 = verbose print output (shows iteration
%                     progress)
%
%   preprocf.h      Preprocessing function (default: pre_sphere)
%   preprocf.params Modifiable parameter structure
%   orthof.h        Orthogonalization function (default: ortho_default)
%   orthof.params   Modifiable parameter structure
%   denf.h          Denoising function (default: denoise_fica_tanh)
%   denf.params     Modifiable parameter structure
%   stopf.h         Stopping criteria function (default: default_stop)
%   stopf.params    Modifiable parameter structure
%
%   reportf         Vector or list of iteration reporting functions.
%   report          Reporting data used by reporting functions
%
%   alphaf.h        Denoise normalization function (default:none)
%   alphaf.params   Modifiable parameter structure
%   betaf.h         Denoise spectral shift function (default: none)

    
function state = dss_create_state(X_or_state, parameters)
% Initializes DSS state structure based on existing state
% and given parameters.
%   state = dss_create_state(X or state, parameters)
%     X           Mixed source, matrix with row vectors as signals.
%     state       New or updated persistent algorithm state structure
%     parameters  Optional parameters that are included in the state.
%                 Overwrites parameters in the state variable.
%
% Description of parameter and state variables:
%   algorithm       DSS algorithm
%                     'defl' = Deflation approach (default)
%		      'symm' = Symmetric approach 
%		      'pca'  = Linear PCA DSS
%   sdim            Number of components to be extracted
%   wdim            Dimension of the data after whitening (preprocessing)
%   verbose         Verbosity
%                     0 = no print output
%                     1 = terse print output (default)
%                     2 = more detailed print output 
%                     3 = verbose print output (shows iteration
%                     progress)
%
%   preprocf.h      Preprocessing function (default: pre_sphere)
%   preprocf.params Modifiable parameter structure
%   orthof.h        Orthogonalization function (default: ortho_default)
%   orthof.params   Modifiable parameter structure
%   denf.h          Denoising function (default: denoise_fica_tanh)
%   denf.params     Modifiable parameter structure
%   stopf.h         Stopping criteria function (default: default_stop)
%   stopf.params    Modifiable parameter structure
%
%   reportf         Vector or list of iteration reporting functions.
%   report          Reporting data used by reporting functions
%
%   alphaf.h        Denoise normalization function (default:none)
%   alphaf.params   Modifiable parameter structure
%   betaf.h         Denoise spectral shift function (default: none)
%   betaf.params    Modifiable parameter structure
%   gammaf.h        Adaptive learning rate function (default:none)
%   gammaf.params   Modifiable parameter structure
%
%   alpha           Constant value for alpha (not adaptive, default: 1)
%   beta            Constant value for beta (not adaptive, default: 0)
%   gamma           Constant value for gamma (not adaptive, default: 1)
%
% Internal data and state variables
%   X          Original mixed source
%   Y          Sphered mixed source
%   A          Mixing matrix
%   B          Unmixing matrix (for X)
%   W          Matrix of all/found projection vectors (for Y)
%   s          Estimate of the current source component (deflation)
%   w          Estimate of the current projection vector (deflation)
%   w_old      Projection vector of the previous iteration (deflation)
%   S          Estimate of all the signal components (symmetric)
%   W_old      Projection vector matrix of the previous iteration (symmetric)
%   iteration  Current iteration number
%   component  Index of currently calculated component (deflation)
%   V          Sphering matrix
%   dV         De-sphering matrix
%
% There are three ways to give values for alpha, beta and gamma:
%  1) Constant value (alpha, beta, gamma),
%  2) function handle (alphaf, betaf, gammaf) with
%    a) constant value (adapt_... = 0) or
%    b) adaptive value (adapt_... = 1)

% Copyright (C) 2004, 2005 DSS MATLAB package team (dss@cis.hut.fi).
% Distributed by Laboratory of Computer and Information Science,
% Helsinki University of Technology. http://www.cis.hut.fi/projects/dss/.
% $Id$

if nargin<1
  error('DSS initialization requires state structure with input data.');
end