Hi all,
This is a little bit off topic but I'm trying to create a nxn array like
the following in SQL:
{{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}}
select array_ndims('{{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}}'::float[][]);
-- 2
select array_dims('{{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}}'::float[][]);
-- [1:4][1:4]
select pg_typeof('{{0,1,2,3},{1,0,3,2},{2,3,0,4},{3,2,4,0}}'::float[][]);
-- double precision[]
So I came up with the following:
select array_agg(arow) as dm from (
select i, array_agg(dist) as arow from (
select a.source_id as i,
b.source_id as j,
st_distance(st_makepoint(a.x, a.y),
st_makepoint(b.x, b.y)) as dist
from tsp_00 a, tsp_00 b
order by a.source_id, b.source_id
) as foo group by i order by i
) as bar;
But I get the following error:
ERROR: could not find array type for data type double precision[]
********** Error **********
ERROR: could not find array type for data type double precision[]
SQL state: 42704
So the question is how can I construct float[][] object like the
constant using sql?
I would like to use this in pgRouting to build a distance matrix and
pass it to our TSP solver, like:
select * from pgr_tsp(
(select array_agg(arow) as dmatrix from (
select i, array_agg(dist) as arow from (
select a.source_id as i,
b.source_id as j,
st_distance(st_makepoint(a.x, a.y),
st_makepoint(b.x, b.y)) as dist
from tsp_00 a, tsp_00 b
order by a.source_id, b.source_id
) as foo group by i order by i
) as bar),
0
);
Thanks,
-Steve
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