MATLAB: I Want to perform element wise matrix multiplication

matrix

I have used the following code but getting an error message

I1=imread('abc.gif');
a=I1(1:3,1:3);
b=[-3 4 5;6 -7 1;-2 -4 -6];
c=a.*b;

The error message obtained is listed below Error using .* Integers can only be combined with integers of the same class, or scalar doubles.

How to clear this error

I1=imread('abc.gif');
a=I1(1:3,1:3);
b=uint8([-3 4 5;6 -7 1;-2 -4 -6]);
c=a.*b;

You see you can multiply only same classes. Class of a is uint8, so you need to convert b into the same class.

B = reshape(permute(A,[2 1 3]),3,[])'

Start with "If an entry in B is greater than or equal to zero": You can either run a loop over all elements of B or use "logical indexing":

% Linear indexing:
for k = 1:numel(B)
   if B(k) >= 0
     ...
   end
end

Or two indices for rows and columns:

for r = 1:size(B, 2)
  for c = 1:size(B, 1)
    if B(r, c) >= 0
       ...
    end
  end
end

Or "logical indexing":

index = (B >= 0);
disp(B(index))

Now try to use this to modify B. Use the mentioned terms to search in the documentation and in the internet.