sink: { S[] -> a[] }
must_source: { T[i] -> a[] : 0 <= i < 10 and i mod 2 = 0 }
may_source: { T[i] -> a[] : 0 <= i < 10 and i mod 2 = 1 }
schedule_map: { T[i] -> [0,i]; S[] -> [1,0] }