recsFirstGuess finds a first guess using the perfect foresight solution
 
  recsFirstGuess tries to find a first-guess for the rational expectations model
  by solving the corresponding perfect foresight solution on all the grid points
  of the state variables. By default, it considers that the model goes back to
  its deterministic steady state in 50 periods.
 
  INTERP = recsFirstGuess(INTERP,MODEL,S,SSS,XSS) uses the interpolation structure
  defined in the structure INTERP to fit the perfect foresight solution of the
  model defined in the structure MODEL. The grid of state variables is provided in
  the n-by-d matrix S. A first guess for the steady state of the model is provided
  in SSS and XSS for state and response variables. recsFirstGuess returns an
  interpolation structure, INTERP, containing the first guess.
  INTERP is a structure, which has to include the following fields:
     fspace       : a definition structure for the interpolation family (created
                    by the function fundef)
  MODEL is an object created by recsmodel.
 
  INTERP = recsFirstGuess(INTERP,MODEL,S,SSS,XSS,OPTIONS) solves the problem
  with the parameters defined by the structure OPTIONS. The fields of the
  structure are
     eqsolver         : 'fsolve', 'lmmcp' (default), 'ncpsolve' or 'path'
     eqsolveroptions  : options structure to be passed to eqsolver (default:
                        empty structure)
     fgmethod         : 'auto' (default), 'perturbation', 'perfect-foresight' or
                        'steady-state'
     T                : integer defining the time horizon at which the model is
                        supposed to converge to its steady state (default: 50)
     UseParallel      : 'always' (default) to use parallel calculation (require
                        Parallel Computing Toolbox)' or never'
 
  [INTERP,X] = recsFirstGuess(INTERP,MODEL,S,SSS,XSS,...) returns X, n-by-m matrix,
  containing the value of the response variables in the first period.
 
  [INTERP,X,Z] = recsFirstGuess(INTERP,MODEL,S,SSS,XSS,...) returns Z, n-by-p matrix,
  containing the value of the expectations variables in the first period.
 
  [INTERP,X,Z,EXITFLAG] = recsFirstGuess(INTERP,MODEL,S,SSS,XSS,...)
 
  [INTERP,X,Z,EXITFLAG,OUTPUT] = recsFirstGuess(INTERP,MODEL,S,SSS,XSS,...)