exa-analytics / exa

The exa framework for data management, processing, and visualization
https://exa-analytics.github.io/exa
Apache License 2.0
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Issue with unit conversions #213

Closed herbertludowieg closed 3 years ago

herbertludowieg commented 4 years ago

Describe the bug I've been comparing some values that we have for the unit conversions on exa with the values of energy converter from NIST and have found some differences. I have been concentrating on the Energy conversions as those are the ones that I have been using very often.

To Reproduce

>>> from exa.util.units import Energy
>>> Energy['J', 'eV']
6.241506363094e+18

Expected 6.241 509 074 e+18 While the difference is nearly insignificant I think we need to be careful of putting in unit conversions that are not matching those from NIST.

>>> from exa.util.constants import electron_volt
>>> electron_volt.value
1.602176621e-19

Expected 1.602 176 634 e-19 from ascii table in NIST

Update It seems that there were some differences between the 2014 and the current 2018