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: SimPanelIndexes_FHorz_Case1_noz_semiz_aggsemiz.m
    path of file: ./repos/VFIToolkit-matlab/SimulateTimeSeries/FHorz
    
    the code of the file until where you have to start completion: function SimPanel=SimPanelIndexes_FHorz_Case1_noz_semiz_aggsemiz(InitialDist,Policy,n_d,n_a,N_j, simoptions)
% Simulates a panel based on PolicyIndexes of 'numbersims' agents of length
% 'simperiods' beginning from randomly drawn InitialDist. (If you use the
% newbirths option you will get more than 'numbersims', due to the extra births)
%
% InitialDist can be inputed as over the finite time-horizon (j), or
% without a time-horizon in which case it is assumed to be an InitialDist
% for time j=1. (So InitialDist is either n_a-by-n_z-by-n_j, or n_a-by-n_z)

N_a=prod(n_a);
N_semiz=prod(n_semiz);
N_d=prod(n_d);


    
function SimPanel=SimPanelIndexes_FHorz_Case1_noz_semiz_aggsemiz(InitialDist,Policy,n_d,n_a,N_j, simoptions)
% Simulates a panel based on PolicyIndexes of 'numbersims' agents of length
% 'simperiods' beginning from randomly drawn InitialDist. (If you use the
% newbirths option you will get more than 'numbersims', due to the extra births)
%
% InitialDist can be inputed as over the finite time-horizon (j), or
% without a time-horizon in which case it is assumed to be an InitialDist
% for time j=1. (So InitialDist is either n_a-by-n_z-by-n_j, or n_a-by-n_z)

N_a=prod(n_a);
N_semiz=prod(n_semiz);
N_d=prod(n_d);

%% Check which simoptions have been declared, set all others to defaults 
if exist('simoptions','var')==1
    %Check simoptions for missing fields, if there are some fill them with
    %the defaults
    if ~isfield(simoptions, 'polindorval')
        simoptions.polindorval=1;
    end