?x⍴2 when ⎕io←0 Index   <<   >>


  b←?1e6⍴2
             13.1        13.2
time       6.64e¯2     3.76e¯2
space      5000056     1125040

b←?1e6⍴2 then time +/b
             13.1        13.2
+/b        3.42e¯3     1.22e¯4