Add values of inputs a and b.
if a and b are numbers: y = a+b
if a is a vector and b a number: y[i] = a[i]+b
if a and b are vectors: y[i] = a[i]+b[i]
Usage:
ADD a b
Inputs:
a
A number or vector.
b
A number or vector.
Outputs:
y
A number or vector (same type as a).