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FHIR / Ucum-java

FHIR Java library providing UCUM Services
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comparable units should be reduced on division #19

Open VladimirAlexiev opened 3 years ago

VladimirAlexiev commented 3 years ago

(This poor issue is looking for a home, was posted as https://github.com/unitsofmeasurement/uom-systems/issues/182 but evicted from that project)

I use UCUM on the semantic web through LINDT (https://github.com/OpenSensingCity/jena-ucum by @maximelefrancois86, @Antoine-Zimmermann).

I'm trying to find the conversion factor of LB-PER-H for https://github.com/qudt/qudt-public-repo/issues/285 (@steveraysteveray). I tried this query at https://ci.mines-stetienne.fr/lindt/playground.html:

PREFIX cdt: <http://w3id.org/lindt/custom_datatypes#> 
select ("1 [lb_av]/h"^^cdt:ucum / "1 kg/s"^^cdt:ucum as ?conv) {}

The result is "1.0 s.[lb_av]/h/kg"^^cdt:dimensionless. This might be formally correct but is highly useless because s.[lb_av]/h/kg is a dimensionless unit (the factor I'm looking for), but is left unreduced. I expect to get:

I'm posting this here (@grahamegrieve) instead of jena-ucum because I guess it comes from the core java-ucum engine.

Why is this important: java-ucum includes a bunch of conversion factors and this is the most natural way to get them out.

We have a big discussion at https://github.com/w3c/sparql-12/issues/129 whether UoM factors should be used as encoded in Java (LINDT), or should be explicitly put into triples (QUDT), and being able to get them out of java-ucum will provide a bridge.

https://github.com/unitsofmeasurement/unit-api/discussions/225 is a bit related (exposing the multiplication factor of a UnitConverter)

grahamegrieve commented 3 years ago

What would this look like as a test case in UcumFunctionalTests.xml (\src\test\resources)?

VladimirAlexiev commented 3 years ago

@grahamegrieve https://github.com/FHIR/Ucum-java/pull/20

VladimirAlexiev commented 2 years ago

Hi @grahamegrieve , any ETA on implementing this feature? I've provided a unit test

grahamegrieve commented 1 year ago

my apologies for ignoring this. Embarrassing I did it for so long. But what's the issue. The test passes as is?