Is multiplying a matrix or a constant with another constant and multiplying a const. with a variable which stores a constant different?

Respected Sirs, I have a loop running about 1000 times.I am using an equation like

 while...
   for i=1:3
     x(i) = a(i) + a(i)*(b(:,i)).^1.2
   end
 end

and i'm getting some output, BUT when i use this form

b=1.2;
while...
 for i=1:3
   x(i) = a(i) + a(i)*(b(:,i)).^b
 end
end

i get output as [NaN NaN]

why is it happening?? please help!!

Answer 1

[per isakson]

Here are some links on debugging in Matlab

• Debugging in MATLAB
• Debugging session
• Debugging Approaches

.

BTW: b=1.2; overwrites the array b(:,i)