Opened 3 years ago

Last modified 3 years ago

## #19093 new defect

# bug in units conversion

Reported by: | schymans | Owned by: | |
---|---|---|---|

Priority: | major | Milestone: | sage-6.9 |

Component: | symbolics | Keywords: | units |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

The .convert() function converts units to their base units, e.g.

sage: (units.energy.joule).convert()

kilogram*meter^2/second^2

The units of heat capacity are joule/kelvin/kilogram and since joule is not a base unit, it should be possible to convert them to base units. However, this throws an error:

sage: (units.energy.joule/units.temperature.kelvin/units.mass.kilogram).convert()

Traceback (click to the left of this block for traceback) ... ValueError: Cannot convert

This seems to be the case whenever something is divided by temperature.

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Goodness, did I really create this ticket only 3 weeks ago? Just googled it again and found the same issue asked by myself 2 years ago with a proposed workaround by Eviatar Bach: http://ask.sagemath.org/question/10260/convert-derived-si-units-to-base-units/