Expand vector along third dimension

My question is simply, but I cannot figure out how to do it.

Assume I have a vector K=[K_1,..,K_n] then I would like to create a three dimensional matrix M with first dimension equal to x, second dimension equal to y and third dimension equal to n such that M(:,:,1)=K1*ones(x,y), M(:,:,2)=K2 * ones(x,y) etc. I know of course I can loop, but I am expecting a neat one-liner exists.

Answer 1

[Matt J]

I have a matrix S which is x times y. Then I would subtract each element of K (what I wanted to use the extra dimension for), take the positive part (i.e. max of the result and 0) and sum out the first dimension x to get a y times n matrix.

 K=reshape(K,1,1);
 result = squeeze( sum( max(  bsxfun(@minus,S,K), 0), 1 )  )

[Matt J]

Henrik's comment moved from an "Answer" to here:

That is one sexy line of code :D Thanks!

Answer 2

[Matt J]

but I am expecting a neat one-liner exists.

It does

    M=repmat(  reshape(K,1,1,[]),   x, y);

but it is often better to use BSXFUN when applicable. That way you don't have to allocate any actual memory for duplicate data.