The drastic sum of two real scalars x and y is:

     max (x, y)     if min (x, y) == 0
     1              otherwise
 

For one vector argument, apply the drastic sum to all of the elements of the vector. (The drastic sum is associative.) For one two-dimensional matrix argument, return a vector of the drastic sum of each column.

For two vectors or matrices of identical dimensions, or for one scalar and one vector or matrix argument, return the pairwise drastic sum.

See also: algebraic_product, algebraic_sum, bounded_difference, bounded_sum, drastic_product, einstein_product, einstein_sum, hamacher_product, hamacher_sum