Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Hi,
I would like to know if the following statements about
terminologies used in VisAD unit system are correct:
* "quantity name" is something like "length"
* "unit name" is like "meter"
* for BaseUnit "unit symbol" is "unit identifier", and is like "m"
* "identifier" for derived unit is the same as the BaseUnit if
derived from one BaseUnit otherwise "null", unless assigned
explicitely
* "unit defination" is "unit identifier" for BaseUnit and
PromiscuousUnit
* "unit defination" is composed by getIdentifier() for Derived
and ScaledUnit
Say if I creat a unit
foo=SI.meter.multiply(2);
and another unit
bar= DerivedUnit({SI.meter},{2});
Are foo and bar actually the same class objects? If yes,
why does DerivedUnit.multiply() return Unit instead of
DerivedUnit? If not, why not?
What should I do if I want to give foo an identifier?
Why doesn't the Unit class have a method to set identifier?
More generally, I would like to know why are BaseUnit, DerivedUnit
and ScaledUnit on the same level of inheritance hierarchy?
Conceptually a BaseUnit is a DerivedUnit that has undergon
zero/no derivation, therefore can be treated "a kind
of", or "a subset of", or a subclass of what is now called
the DerivedUnit, and ScaledUnit can be also seen as a
special case of DerivedUnit. The Developers Guide (2.5 years
old) doesn't mention what is the thinking behind the DerivedUnit
and ScaledUnit.
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