what's the problem with my for loop ?

function [responces] = int_method(records,DT,Tn)
%This function calculates interpolation method's parameter and spectral
%displacement and spectral pseudo-velocity and pseudo-acceleration.

% Parameter defining:
M = 1;            % Mass in units of kg.
XI = 0.05;        % damping ration.

% Calculation of displacement, pseudo-velocity and pseudo-acceleration
% spectrums:
for m=1:length(DT);

      for i=1:numel(Tn);
          Wn=(2*pi)/Tn(i,1); % Radial/Angular frequency in units of rad/sec.
          K=Wn^2*M; % Stiffness in units of kg/cm
          Wd=Wn*sqrt(1-XI^2); % rad/sec

          DT1=DT(m);

          a=(exp(-XI*Wn*DT1));
          b=((2*XI)/(Wn*DT1));
          c=(XI/sqrt(1-XI^2));
          d=((Wn)/(sqrt(1-XI^2)));
          e=sin(Wd*DT1);
          f=cos(Wd*DT1);

          A=a*(c*e+f);
          B=a*(e/Wd);
          C=(1/K)*(b+a*((((1-2*XI^2)/(Wd*DT1))-c)*e-(1+b)*f));
          D=(1/K)*(1-b+a*(((2*XI^2-1)/(Wd*DT1))*e+b*f));
          A1=-a*(d*e);
          B1=a*(f-c*e);
          C1=(1/K)*(-1/DT1+a*((d+c/DT1)*e+f/DT1));
          D1=(1/(K*DT1))*(1-a*(c*e+f));

          for j=1:numel(records.Ag{1,m})-1; 

              % Intial conditions:
              u(1,1)=0;
              v(1,1)=0;

              u(j+1,1)=A*u(j,1)+B*v(j,1)+C*records.Ag{1,m}(j,1)+D*records.Ag{1,m}(j+1,1);
              v(j+1,1)=A1*u(j,1)+B1*v(j,1)+C1*records.Ag{1,m}(j,1)+D1*records.Ag{1,m}(j+1,1);
          end

          responces.Sd{1,m}(i,1)=max(abs(u));                % Spectral displacement (cm).
          responces.Spv{1,m}(i,1)=Wn*responces.Sd{1,m}(i,1);   % Spectral pseudo-velocity (cm/s).
          responces.NSpv{1,m}(i,1)=responces.Spv{1,m}(i,1)./records.MVg{1,m}; % Spectral shape
          responces.Spa{1,m}(i,1)=Wn^2*responces.Sd{1,m}(i,1); % Spectral psudo acceleration (cm/s^2).
      end
  end
  responces.MeanNSpv=(mean((cell2mat(responces.NSpv))'))';
  end

it does'nt give right answer

record argument contains 8 accelerogram

DT argument contais records sampling time

Tn is equal to Tn = 0.01:0.01:4; % periods in units of sec.

when i use one accelerogram the answer is rigth but as i use 2 or more it doesn't give the right answer for each one.