select a+b from ( select unnest(ARRAY[0,5.3,1,7.1]) as a, unnest(ARRAY[4,0.7,8,3]) as b ) as c
select array_agg(a+b) from (select unnest('{0,5.3,1,7.1}'::float[]) as a, unnest('{4,0.7,8,3}'::float[]) as b) x
array_agg-------------- {4,6,9,10.1}(1 row)
select array_agg(('{0,5.3,1,7.1}'::float[])[i] + ('{4,0.7,8,3}'::float[])[i] order by i) from generate_subscripts('{0,5.3,1,7.1}'::float[], 1) as a(i)