Typesetting values with units requires care to ensure that the
combined mathematical meaning of the value plus unit
combination is clear. In particular, the SI units system lays
down a consistent set of units with rules on how they are to be
used. However, different countries and publishers have
differing conventions on the exact appearance of numbers (and
units). A number of LaTeX packages have been developed to
provide consistent application of the various rules: siunits,
sistyle, unitsdef and units are the leading examples. The
numprint package provides a large number of number-related
functions, while dcolumn and rccol provide tools for
typesetting tabular numbers. The siunitx package takes the best
from the existing packages, and adds new features and a
consistent interface. A number of new ideas have been
incorporated, to fill gaps in the existing provision. The
package also provides backward-compatibility with siunits,
sistyle, unitsdef and units. The aim is to have one package to
handle all of the possible unit-related needs of LaTeX users.
The package relies on LaTeX 3 support from the l3kernel and
l3packages bundles.
