How to multiply a vector of scalars with a vector of vectors in Matlab? This sounds a bit strange, I'll explain it further.
Assume we have a row vector $c = (c_1,c_2,\dots,c_n)$ and we have $n$ column vectors $v_i\in\mathbb R^4$ for $i\in\{1,\dots,n\}$. The $c$ is stored in Matlab as as vector
c = [c1 c2 c3 ... cn]
and the vectors $v_i$ are stored in a matrix
V = [v1 v2 v3 ... vn].
I want now to calculate the matrix $(c_1 v_1, c_2 v_2, \dots, c_n v_n)$ in Matlab. This can be done easily by
for i = 1:n
   prod(1:4,i) = c(i)*V(:,i);
end

But I want it to do without any for loop and without any repmat-command as its rather slow this way.

I'm not sure whether this is on-topic for this site, but the command you want is:
bsxfun(@times,V,c)

