Red Hat Bugzilla – Bug 79845
Package info (from rpmquery -i) incorrect
Last modified: 2005-10-31 17:00:50 EST
Description of problem:
The 'units' package description states that the program "can only handle
multiplicative scale changes" whereas the man page states that that is not the
case, and even gives an example (which works) to contradict that.
Version-Release number of selected component (if applicable):
rpmquery -i units
"Units can only handle multiplicative scale changes (i.e., it can not tell you
how to convert from Celsius to Fahrenheit, which requires an additive step in
addition to the multiplicative conversion)."
"The `units' program can handle multiplicative scale changes as well as
nonlinear conversions such as Fahrenheit to Celsius."
Farenheit to Celsius definitely _is_ linear. It's just y = Ax +B.
The point, in case it wasn't clear enough already, is that the two texts are
contradictory, and that the package description would lead one to believe that
it cannot be used for that type of conversion -- whereas it can.
fixed in 1.80-3
A linear transformation T has the property that T(x+z)=T(x)+T(z).
(That's part of the definition of linear transformation.) If you try
your form T(x)=ax+b you'll find that T(x)+T(z)=ax+b+az+b=a(x+z)+2b but
T(x+z)=a(x+z)+b. So the property does NOT hold, and hence the form
T(x)=ax+b is NOT a linear transformation. The Fahrenheit to Celsius
transformation y=ax+b is an affine transformation.
*** Bug 100404 has been marked as a duplicate of this bug. ***