Question

There are matices A(n,1), B(n,1) and the following condition inside a loop

for i=1:m
   if ( A(i, 1) > error )
      B(i,1) = 0;
   else
      B(i,1) = exp (-A(i,1) / 100)
   end
end

How to rewrite this condition without using any loop? Is it possible something like that

 if ( A(:, 1) > error )
      B(:,1) = 0;
   else
      B(:,1) = exp (-A(:,1) / 100)
 end

Answer 1

Use logical indexing:

idxs = (A > error);
B( idxs) = 0;
B(~idxs) = exp(-A(~idxs) / 100);