need help with a for loop

Hi All, I am trying to get this for loop to execute, and I'm not sure what I am doing wrong here. I was wondering if you could help me out. It keeps telling me that my matrix dimensions must agree, but I'm pretty sure that they do.

%Define Variables
A=[100,0,.1;.01,50,0;0,.01,200];
b=[1;1;1];
x=A\b;
r=b-A*x;
c=A\r;
%My for loop
a=1:3;
for a=1:length(a)
  r(a)= b+(A*x(a))
  c(a)=A\r(a)
  x_new=x(a)+c(a)
end

any help you could give me would be really appreciated

[per isakson]

"pretty sure that they do" &nbsp Check b+(A*x(a)) once more

Replace the name of the counter a by e.g. jj

And see Debug a MATLAB Program

Answer 1

[freebil]

In the second line of the for loop, b is 3x1 and (A*x(a)) is 3x3. So, you cant sum these. For summing, they must have identical dimensions.