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Posted to dev@jena.apache.org by "Andy Seaborne (Jira)" <ji...@apache.org> on 2020/08/15 16:00:02 UTC
[jira] [Commented] (JENA-1943) Increase Precision of Decimal
Calculation Results
[ https://issues.apache.org/jira/browse/JENA-1943?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17178302#comment-17178302 ]
Andy Seaborne commented on JENA-1943:
-------------------------------------
There are several things going on in the test case: is it just the "1/" operation?
{noformat}
SELECT ( 1/'10000000000000000000000000'^^xsd:decimal AS ?X) {}
{noformat}
> Increase Precision of Decimal Calculation Results
> -------------------------------------------------
>
> Key: JENA-1943
> URL: https://issues.apache.org/jira/browse/JENA-1943
> Project: Apache Jena
> Issue Type: Bug
> Components: ARQ
> Affects Versions: Jena 3.14.0, Jena 3.16.0
> Reporter: Jan Martin Keil
> Priority: Major
>
> The precision of calculation results with type {{xsd:decimal}} is limited without need.
> An Example:
> {code:java}
> import org.apache.jena.query.QueryExecutionFactory;
> import org.apache.jena.rdf.model.ModelFactory;
> import org.junit.jupiter.api.Test;
> public class MaxDecimalDivissionPrecissionTest {
> @Test
> public void maxDecimalDivissionPrecission() {
> String query = "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> "//
> + "SELECT"//
> + " ( STR(1/STRDT(\"1000000000000000000000000\", xsd:decimal)) AS ?times10)"//
> + " ( STR(1/STRDT(\"10000000000000000000000000\", xsd:decimal)) AS ?calculated)"//
> + " (DATATYPE(1/STRDT(\"10000000000000000000000000\", xsd:decimal)) AS ?type)"//
> + " ( STR( STRDT(\"0.0000000000000000000000001\", xsd:decimal)) AS ?direct)"//
> + " ( STR(1/STRDT(\"0.0000000000000000000000000000000000000000000001\", xsd:decimal)) AS ?large)"//
> + "WHERE {}";
> System.out.println(QueryExecutionFactory.create(query, ModelFactory.createDefaultModel()).execSelect().next().toString().replace(" (", "\n("));
> }
> }
> {code}
> Output:
> {code:java}
> ( ?times10 = "0.000000000000000000000001" )
> ( ?direct = "0.0000000000000000000000001" )
> ( ?calculated = "0.0" )
> ( ?large = "10000000000000000000000000000000000000000000000.0" )
> ( ?type = xsd:decimal )
> {code}
>
> I would expect {{?calculated == ?direct}}. This only affects very small numbers, very large numbers are not affected. I also checked [Wikibase|https://query.wikidata.org/#PREFIX%20xsd%3A%20%3Chttp%3A%2F%2Fwww.w3.org%2F2001%2FXMLSchema%23%3E%20%0ASELECT%0A%20%20%28STR%281%2FSTRDT%28%221000000000000000000000000%22%2C%20xsd%3Adecimal%29%29%20AS%20%3Ftimes10%29%0A%20%20%28STR%281%2FSTRDT%28%2210000000000000000000000000%22%2C%20xsd%3Adecimal%29%29%20AS%20%3Fcalculated%29%0A%20%20%28STR%28%20%20STRDT%28%220.0000000000000000000000001%22%2C%20xsd%3Adecimal%29%29%20AS%20%3Fdirect%29%0A%20%20%28DATATYPE%28STRDT%28%220.0000000000000000000000001%22%2C%20xsd%3Adecimal%29%29%20AS%20%3Ftype%29%0A%20%20%28STR%281%2FSTRDT%28%220.0000000000000000000000000000000000000000000001%22%2C%20xsd%3Adecimal%29%29%20AS%20%3Flarge%29%0AWHERE%20%7B%7D] and RDF4J and did not find this limitation. Please consider to remove this limitation as I need higher precision in a view cases in a project.
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