Add map for 2 input args.

j/abstractarray.j

@@ -842,39 +842,48 @@ isempty(a::AbstractArray) = (numel(a) == 0)
 #map(f, v::AbstractVector) = [ f(v[i]) | i=1:length(v) ]
 #map(f, M::AbstractMatrix) = [ f(M[i,j]) | i=1:size(M,1), j=1:size(M,2) ]
 
+## TODO: How to generalize map to n input args?
 function map_to(dest::AbstractArray, f, A::AbstractArray)
     for i=1:numel(A)
         dest[i] = f(A[i])
     end
     return dest
 end
 
-function map(f, A::AbstractArray)
-    if isempty(A)
-        return A
+function map_to(dest::AbstractArray, f, A::AbstractArray, B::AbstractArray)
+    for i=1:numel(A)
+        dest[i] = f(A[i], B[i])
     end
+    return dest
+end
+
+function map(f, A::AbstractArray)
+    if isempty(A); return A; end
     first = f(A[1])
     dest = similar(A, typeof(first))
-    map_to(dest, f, A)
-    # dest[1] = first
-    # for i=2:numel(A)
-    #     dest[i] = f(A[i])
-    # end
-    # return dest
-end
-
-#obsolete code, mainly here for reference purposes, use gen_cartesian_map
-function cartesian_map(body, t::Tuple, it...)
-    idx = length(t)-length(it)
-    if idx == 0
-        body(it)
-    else
-        for i = t[idx]
-            cartesian_map(body, t, i, it...)
-        end
-    end
+    return map_to(dest, f, A)
 end
 
+function map(f, A::AbstractArray, B::AbstractArray)
+    if size(A) != size(B); error("Input size and shape should be same"); end
+    if isempty(A); return A; end
+    first = f(A[1], B[1])
+    dest = similar(A, typeof(first))
+    return map_to(dest, f, A, B)
+end
+
+## Obsolete - Mainly here for reference purposes, use gen_cartesian_map
+# function cartesian_map(body, t::Tuple, it...)
+#     idx = length(t)-length(it)
+#     if idx == 0
+#         body(it)
+#     else
+#         for i = t[idx]
+#             cartesian_map(body, t, i, it...)
+#         end
+#     end
+# end
+
 ## Transpose, Permute ##
 
 reverse(v::AbstractVector) = [ v[length(v)-i+1] | i=1:length(v) ]