I'm multiplying 2 3x3 matrices and the answer is displaying as a 1x9, how can i fix this?

A=[0.4 0.1 0.2;0.3 0.7 0.7;0.3 0.2 0.1];
b=[0.4 0.1 0.2;0.3 0.7 0.7;0.3 0.2 0.1];
for i = 1:40
 b = A*b;
 fprintf('i=%3d b=[',i);
 for j = 1:9
 fprintf('%12.6f',b(j));
 end
 fprintf(']\n');
end

Answer 1

[Star Strider]

Your code is printing what you told it to print.

Try this:

A=[0.4 0.1 0.2;0.3 0.7 0.7;0.3 0.2 0.1];
b=[0.4 0.1 0.2;0.3 0.7 0.7;0.3 0.2 0.1];
for i = 1:40
    b = A*b;
    fprintf('i=%3d b=[',i);
    fprintf('%12.6f %12.6f %12.6f\n%12.6f %12.6f %12.6f\n%12.6f %12.6f %12.6f',b');
    fprintf(']\n');
end

[Terry Poole]

That did it!!! Sorry, I'm terribly new to Matlab. I knew it was somthing inside the for loop, I actually tried the %12.6f multiple times to declare the row's/columns it didn't occur to me to remove the J all together, I assumed I needed to declare a new letter to define the answer of A*b to the ith iteration. Thank you so much!!!

[Star Strider]

As always, my pleasure!

No apologies necessary. We were all new to MATLAB (and to programming in general) at one point in our lives. We’re all still learning.

The solution is in understanding how fprintf (and sprintf) intrepret matrix arguments. It’s worthwhile experimenting with it when time permits.

It is quite understandable that you would consider the need to subscript your matrix so it prints the way you want it to, however since you have already defined your matrix, printing it is relatively straightforward.