Index exceeds matrix dimensions

My matlab code is as follows

        function [g,shift,M] = nsgcqwin(fmin,fmax,bins,sr,Ls,varargin)

          % Set defaults
          bwfac = 1;
          min_win = 4;
          fractional = 0;
          winfun = 'hann';
          gamma = 0;

          % Check input arguments

          if nargin < 5
              error('Not enough input arguments');
          end

          if nargin >= 6
              Lvar = length(varargin);
              if mod(Lvar,2)
                  error('Invalid input argument');
              end
              for kk = 1:2:Lvar
                  if ~ischar(varargin{kk})
                      error('Invalid input argument');
                  end
                  switch varargin{kk}
                      case {'min_win'}
                          min_win = varargin{kk+1};
                      case {'gamma'}
                          gamma = varargin{kk+1};
                      case {'bwfac'}
                          bwfac = varargin{kk+1};
                      case {'fractional'}
                          fractional = varargin{kk+1};
                      case {'winfun'}
                          winfun = varargin{kk+1};
                      otherwise
                          error(['Invalid input argument: ', varargin{kk}]);
                  end
              end
          end

          nf = sr/2;

          if fmax > nf
              fmax = nf;
          end

          fftres = sr / Ls;
          b = floor(bins * log2(fmax/fmin));
          fbas = fmin .* 2.^((0:b).'./bins);

          Q = 2^(1/bins) - 2^(-1/bins);
          cqtbw = Q*fbas + gamma; cqtbw = cqtbw(:);

          %make sure the support of highest filter won't exceed nf
          tmpIdx = find(fbas+cqtbw/2>nf,1,'first');
          if (~isempty(tmpIdx))
              fbas = fbas(1:tmpIdx-1);
              cqtbw = cqtbw(1:tmpIdx-1);
          end

          %make sure the support of the lowest filter won't exceed DC
          tmpIdx = find(fbas-cqtbw/2<0,1,'last');
          if (~isempty(tmpIdx))
              fbas = fbas(tmpIdx+1:end);
              cqtbw = cqtbw(tmpIdx+1:end);
              warning(['fmin set to' num2str(fftres*floor(fbas(1)/fftres),6)  ' Hz!']);
          end

          Lfbas = length(fbas);
          fbas = [0;fbas];
          fbas(Lfbas+2) = nf;
          fbas(Lfbas+3:2*(Lfbas+1)) = sr-fbas(Lfbas+1:-1:2);

          bw = [2*fmin; cqtbw; fbas(Lfbas+3)-fbas(Lfbas+1); cqtbw(end:-1:1)];
          fftres = sr / Ls;
          bw = bw / fftres;
          fbas = fbas / fftres;

          % center positions of filters in DFT frame
          posit = zeros(size(fbas));
          posit(1:Lfbas+2) = floor(fbas(1:Lfbas+2));
          posit(Lfbas+3:end) = ceil(fbas(Lfbas+3:end));

          shift = [mod(-posit(end),Ls); diff(posit)];

          if fractional
              corr_shift = fbas-posit;
              M = ceil(bw+1);
          else
              bw = round(bw);
              M = bw;
          end

          for ii = 1:2*(Lfbas+1)
              if bw(ii) < min_win;
                  bw(ii) = min_win;
                  M(ii) = bw(ii);
              end
          end

          if fractional
              g = arrayfun(@(x,y,z) ...
                  winfuns(winfun,([0:ceil(z/2),-floor(z/2):-1]'-x)/y)/sqrt(y),corr_shift,...
                  bw,M,'UniformOutput',0);
          else
                  g = arrayfun(@(x) winfuns(winfun,x),...
                      bw,'UniformOutput',0);

          end

          M = bwfac*ceil(M/bwfac);

          % Setup Tukey window for 0- and Nyquist-frequency
          for kk = [1,Lfbas+2]
              if M(kk) > M(kk+1);
                  g{kk} = ones(M(kk),1);
                  g{kk}((floor(M(kk)/2)-floor(M(kk+1)/2)+1):(floor(M(kk)/2)+...
                      ceil(M(kk+1)/2))) = winfuns('hann',M(kk+1));
                  g{kk} = g{kk}/sqrt(M(kk));
              end
          end

and the error i am getting is this

_Index exceeds matrix dimensions.

Error in nsgcqwin (line 161) bw = [2*fmin; cqtbw; fbas(Lfbas+3)-fbas(Lfbas+1); cqtbw(end:-1:1)];

Error in slicq (line 124) [g,shift,M] = nsgcqwin(fmin,fmax,bins,sr,sl_len,'min_win',min_win,'bwfac',4,'fractional',1,'winfun','modblackharr'); _

[Matt J]

In,

 fbas(Lfbas+3)-fbas(Lfbas+1)

what are the values of Lfbas and what is the size of fbas?