Do the index notation allowed in subs command..If not, what is the alternative... Plz debug the following program.

clc
clear all
syms x1 x2
conv=0.001;
g(2)=x1^3+x2^3-18
mux1=input('enter mean of x1')
mux2=input('enter mean of x2')
sdx1=input('enter sd of x1')
sdx2=input('enter sd of x2')
mu=subs(g(2),{x1,x2},{mux1,mux2})
var=[subs(diff(g(2),x1),{x1,x2},{mux1,mux2})*sdx1]^2+ ...
  [subs(diff(g(2),x2),{x1,x2},{mux1,mux2})*sdx2]^2
sd=sqrt(var)
betav=mu/sd
alpha1=-sqrt([subs(diff(g(2),x1),{x1,x2},{mux1,mux2})*sdx1]^2)/sd
alpha2=-sqrt([subs(diff(g(2),x2),{x1,x2},{mux1,mux2})*sdx2]^2)/sd

% x1_1new=mux1+beta*sdx1*alpha1
% x2_1new=mux2+beta*sdx2*alpha2
% u1_1=(x1_1new-mux1)/sdx1
% u2_1=(x2_1new-mux2)/sdx2
% mu_new=subs(g,{x1,x2},{x1_1new,x2_1new})
% var_new=[subs(diff(g,x1),{x1,x2},{x1_1new,x2_1new})*sdx1]^2+ ...
%     [subs(diff(g,x2),{x1,x2},{x1_1new,x2_1new})*sdx2]^2
% sd_new=sqrt(var_new)
% novar_new=[subs(diff(g,x1),{x1,x2},{x1_1new,x2_1new})*sdx1]*u1_1+ ...
%           [subs(diff(g,x2),{x1,x2},{x1_1new,x2_1new})*sdx2]*u2_1
% beta_1new=(mu_new-novar_new)/sd_new

% iterations begin
i=2;
beta(1)=0;
beta(2)=betav;
mu(1)=mu;
while ((abs(beta(i)-beta(i-1)))/beta(i-1))>conv
  i
  x1(1)=0;
  x2(1)=0; 
  x1(i)= mux1+beta(i)*sdx1*alpha1
  x2(i)= mux2+beta(i)*sdx2*alpha2
  u1(i)= (x1(i)-mux1)/sdx1
  u2(i)= (x2(i)-mux2)/sdx2
  g
  x1(i)
  x2(i)
  mu(i)=subs(g,{x1,x2},{x1(i),x2(i)})
  var(i)=[subs(diff(g,x1),{x1,x2},{x1(i),x2(i)})*sdx1]^2+ ...
          [subs(diff(g,x2),{x1,x2},{x1(i),x2(i)})*sdx2]^2
  sd(i)=sqrt(var(i))
  novar(i)=[subs(diff(g,x1),{x1,x2},{x1(i),x2(i)})*sdx1]*u1(i)+ ...
            [subs(diff(g,x2),{x1,x2},{x1(i),x2(i)})*sdx2]*u2(i)
  beta(i)=(mu(i)-novar(i))/sd(i)
  alpha1(i)=-sqrt([subs(diff(g,x1),{x1,x2},{x1(i),x2(i)})*sdx1]^2)/sd(i)
  alpha2(i)=-sqrt([subs(diff(g,x2),{x1,x2},{x1(i),x2(i)})*sdx2]^2)/sd(i)
  i=i+1
end
beta(i)

[Azzi Abdelmalek]

What is your problem?

[Jan]

At first start to read the "? Help" link. Then use what you have found there to format your code until it is readable. In the next step, show us, where the problem is instead of letting us guess the details. If you ask for an alternative, be as exact as possible: Alternative to what?