cartodb/cartodb-postgresql
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge pull request #80 from CartoDB/sariogonfer-master

Browse Source 
updates quantile bins algorithm
This commit is contained in:
Andy Eschbacher 2015-05-07 10:55:19 -04:00
commit b1e1723e75
2 changed files with 23 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
scripts-available/CDB_QuantileBins.sql
View File

@ -15,18 +15,29 @@ DECLARE
i INT := 1;
reply numeric[];
BEGIN
-- get our unique values
SELECT array_agg(e) INTO in_array FROM (SELECT unnest(in_array) e GROUP BY e ORDER BY e ASC) x;
-- get the total size of our row
element_count := array_upper(in_array, 1) - array_lower(in_array, 1);
-- sort our values
SELECT array_agg(e) INTO in_array FROM (SELECT unnest(in_array) e ORDER BY e ASC) x;
-- get the total size of our data
element_count := array_length(in_array, 1);
break_size := element_count::numeric / breaks;
-- slice our bread
LOOP
IF i > breaks THEN EXIT; END IF;
SELECT e INTO tmp_val FROM ( SELECT unnest(in_array) e LIMIT 1 OFFSET round(break_size * i)) x;
IF i < breaks THEN
IF break_size * i % 1 > 0 THEN
SELECT e INTO tmp_val FROM ( SELECT unnest(in_array) e LIMIT 1 OFFSET ceil(break_size * i) - 1) x;
ELSE
SELECT avg(e) INTO tmp_val FROM ( SELECT unnest(in_array) e LIMIT 2 OFFSET ceil(break_size * i) - 1 ) x;
END IF;
ELSIF i = breaks THEN
-- select the last value
SELECT max(e) INTO tmp_val FROM ( SELECT unnest(in_array) e ) x;
ELSE
EXIT;
END IF;
reply = array_append(reply, tmp_val);
i := i+1;
END LOOP;
RETURN reply;
i := i+1;
END LOOP;
RETURN reply;
END;
$$ language plpgsql IMMUTABLE;
$$ language plpgsql IMMUTABLE;

4
test/CDB_QuantileBinsTest_expect
View File

@ -1,7 +1,7 @@
16
13
29
43
57
71
83
86
99