binaryop broadcasting

broadcasting rule

ncnn BinaryOp accepts blobs with different shape

C = BinaryOp(A, B)

shape notation convention is [w], [w,h], [w,h,c]

type	A	B	C
1	[1]	scalar	[1]
2	[1]	[2]	[2]
3	[1]	[2,3]	[2,3]
4	[1]	[2,3,4]	[2,3,4]
5	[2]	scalar	[2]
6	[2]	[1]	[2]
7	[2]	[2]	[2]
8	[3]	[2,3]	[2,3]
9	[4]	[2,3,4]	[2,3,4]
10	[2,3]	scalar	[2,3]
11	[2,3]	[1]	[2,3]
12	[2,3]	[3]	[2,3]
13	[2,3]	[2,3]	[2,3]
14	[3,4]	[2,3,4]	[2,3,4]
15	[2,3,4]	scalar	[2,3,4]
16	[2,3,4]	[1]	[2,3,4]
17	[2,3,4]	[4]	[2,3,4]
18	[2,3,4]	[3,4]	[2,3,4]
19	[2,3,4]	[2,3,4]	[2,3,4]

some special broadcasting rule exists for model compatibility

special type	A	B	C
1	[2,3,4]	[1,1,4]	[2,3,4]
2	[2,3,4]	[2,3,1]	[2,3,4]
3	[1,1,4]	[2,3,4]	[2,3,4]
4	[2,3,1]	[2,3,4]	[2,3,4]
5	[2,3,4]	[1,3,4]	[2,3,4]
6	[2,3,4]	[2,1,4]	[2,3,4]
7	[1,3,4]	[2,3,4]	[2,3,4]
8	[2,1,4]	[2,3,4]	[2,3,4]