Add pairwise (#1)

Author: nalimilan

src/StatsAPI.jl

@@ -1,3 +1,21 @@
 module StatsAPI
 
+#    pairwise(f, x[, y])
+#
+# Return a matrix holding the result of applying `f` to all possible pairs
+# of entries in iterators `x` and `y`, and return it.
+#
+# This generic function is owned by StatsBase.jl, which is the sole provider
+# of the default definition.
+function pairwise end
+
+#    pairwise!(f, dest::AbstractMatrix, x[, y])
+#
+# Store in matrix `dest` the result of applying `f` to all possible pairs
+# of entries in iterators `x` and `y`, and return it.
+#
+# This generic function is owned by StatsBase.jl, which is the sole provider
+# of the default definition.
+function pairwise! end
+
 end # module