reductionista commented on a change in pull request #475: Kmeans: Convert
python inf and nan values to postgres
URL: https://github.com/apache/madlib/pull/475#discussion_r372017347
##########
File path: src/ports/postgres/modules/kmeans/kmeans_auto.py_in
##########
@@ -151,8 +152,11 @@ def kmeans_auto(schema_madlib, rel_source, output_table,
expr_point, k,
WHERE k = {current_k}),
'{fn_dist}')
""".format(**locals())
- silhouette_vals.append(
- plpy.execute(silhouette_query)[0]['simple_silhouette'])
+ new_silh =
plpy.execute(silhouette_query)[0]['simple_silhouette']
+ new_silh = "Infinity" if math.isinf(new_silh) else new_silh
+ new_silh = "NaN" if math.isnan(new_silh) else new_silh
Review comment:
I think this may result in a SQL error unless we change these values
slightly to "'Infinity'::REAL" and "'NaN'::REAL"
```
select ARRAY[101458.80510776624, 54486.907688432577, 18710.554755872785,
1549.1568578504798, Infinity, Infinity, NaN];
ERROR: column "infinity" does not exist
select ARRAY[101458.80510776624, 54486.907688432577, 18710.554755872785,
1549.1568578504798, Infinity::REAL, 'Infinity', 'NaN'];
ERROR: column "infinity" does not exist
select ARRAY[101458.80510776624, 54486.907688432577, 18710.554755872785,
1549.1568578504798, 'Infinity'::REAL, 'Infinity'::REAL, 'NaN'::REAL];
array
--------------------------------------------------------
{101459,54486.9,18710.6,1549.16,Infinity,Infinity,NaN}
(1 row)
```
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