Each element of the input vector is copied to n_spread elements of the output vector. That is, the output vector is n_spread times as long as the input one and contains blocks of identical values. A typical use would be when the input has a single element which is to be distributed to all elements of a population. In this case, a broadener should be interposed between the source and the population, with n_spread equal to the size of the population. Without the broadener, only the first element of the population would receive the vector input.