MATLAB: Index exceeds matrix dimensions error !!

iterationnewton raphson

I am using newton -raphson method .. the code for newton method is ..
function [x,f,ea,iter] = newtmult (func,x0,es,maxit,varargin)
if nargin<2,error('atleast 2 input arguments required'),end
if nargin<3||isempty(es),es=0.0001;end
if nargin<4||isempty(maxit),maxit=50;end
iter = 0;
x = x0;
while (1)
      [J,f] = func(x,varargin{:});
      [L,U] = lu(J);
      dx = U\(L\f); 
      x = x - dx;
      iter = iter+1;
      ea = 100*max(abs(dx./x));
      if iter>=maxit||ea<=es, break, end
  end
Using this function i am supposed to calculate the values of some variables of other code .. which is as follows :
% open circuit voltage irradiance and temperature dependence
% Voc1 = is the irradiance dependent Voc 
% Voc2 = is the temperature dependent Voc 
% Voc1 has to be calculated using Newton -Raphson method. 
function [J,f] = Voccalculation4(x,varargin)
%v = [ Voc1 Voc2]
Rsh =   417.5; % panel parallel (shunt) resistance.
Ns = 72 ; % no of cells connected in series.
Iph = 5.20;
I0 = 4.54;
G = 1000 ;  % G= irradiance (different values of irradiance ) in W/m^2.
Iph1 = Iph*G;   % Iph = photo-generated current in STC , obtained from previous calculation.
%I01 =  I0*G ; % I0 = dark saturation current in STC,obtained from previous calculation.
Tstc = 298 ;  % Tstc (K) is temperature in kelvin at STC .
K = 1.381e-23; %Boltzmann constant = 1.3806488 × 10-23 m2 kg s-2 K-1 .
q = 1.60e-19; % electron charge in coulombs.
A=1.2;
Vt = (A*K*Tstc)/q  ;   % threshold voltage of cell-diode.
Voc = 42;
T = 320 ; % operating range given in datasheet !
Kv = -0.38;
format short
% G is irradiance here
syms Voc1  Voc2
f1= Voc1 - (log((Iph1*Rsh - Voc1)/(I0*Rsh)))*Ns*Vt;
f2= Voc2 - Voc + Kv(T-Tstc); % sign before Kv is positive in standard equation.
J11 = diff(f1,'Voc1');
J12 = diff(f1,'Voc2');
J21 = diff(f2,'Voc1');
J22 = diff(f2,'Voc2');
f = zeros(2,1);
f(1)= subs (f1,{Voc1,Voc2},{x(1),x(2)});
f(2)= subs (f2,{Voc1,Voc2},{x(1),x(2)});
J = zeros(2,2);
J(1,1) = subs (J11,{Voc1,Voc2},{x(1),x(2)});
J(1,2) = subs (J12,{Voc1,Voc2},{x(1),x(2)});
J(2,1) = subs (J21,{Voc1,Voc2},{x(1),x(2)});
J(2,2) = subs (J22,{Voc1,Voc2},{x(1),x(2)});
J
I have been stuck on this code for weeks now … after trying recommendations to other users .. I am finally posting it here .. any help will be greatly appreciated !!! Thanks in advance .

Best Answer

My guess is that you're missing a multiplication operator:
f2= Voc2 - Voc + Kv*(T-Tstc);
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