Array broadcasting slower than numpy?

[jling]

@chunjiw

		v[1:i] .+= @view w[end-i+1:end]
		v[i+1:end] .+= @view w[1:end-i]

change to

               @views v[1:i] .+= w[end-i+1:end]
               @views v[i+1:end] .+= w[1:end-i]