MATLAB: How to vectorize this code

for loopvectorization

 for k=1:1:3
    for j=1:1:160
       for i=1:1:160
            for a=1:1:9
                %Cover1 in Share1
                if enshare1{i,j}(a)==1
                    enshare1{i,j}(a)=cover1(i,j,k);
                else
                    enshare1{i,j}(a)=cover1(i,j,k)-1;
                end
                %Cover2 in Share2
                if enshare2{i,j}(a)==1
                    enshare2{i,j}(a)=cover2(i,j,k);
                else
                    enshare2{i,j}(a)=cover2(i,j,k)-1;
                end
            end
        end
     end
  end
The i,j and k for loops are not in the same way as specified here. I added them so that one need not wonder where those 3 variables came from. I want to vectorize the inner 'a' for loop.
Thanks

Best Answer

 isOne = enshare1{i,j} == 1 ;
 enshare1{i,j}(:) = cover1(i,j,k)-1 ;
 enshare1{i,j}(isOne) = cover1(i,j,k) ;
and same for cover2/share2. The second line above should be
 enshare1{i,j}(~isOne) = cover1(i,j,k)-1 ;
but I guess that is is more efficient to skip this indexing and let the 3rd line update relevant elements.
A more efficient but not as clean (up to me) way to do it would be
 isOne = enshare1{i,j} == 1 ;
 enshare1{i,j} = isOne * cover1(i,j,k) + ~isOne * (cover1(i,j,k)-1) ;
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