Section 24 Units of Measure
Units of measure can be given xml treatment too with the
quantity
element. In LaTeX, the siunitx
package is loaded to achive unit handling. Since that package only offers SI units, some other common units will be added by PreTeXt in the preamble. In HTML, the capabilities of siunitx
are simulated, weakly. Note that at present, you should not attempt to use the quantity
element within a math environment.The value of gravitational constant \(g\) is 9.8 m⁄s2. Force is measured in kg·m⁄s2, also known as one N. A quantity with rather ridiculous units is 23 µha23⁄°C·s2. One Hz is the same as 1⁄s. You can have a unitless quantity, like 42, which may help with consistency between such numbers and units in the LaTeX output. Some non-SI units are available, such as the absurd °F·ft·lb⁄gal. The LaTeX command
\pi
is recognized within mag
in conversions to HTML, which is consistent with the behavior with a conversion to LaTeX, for example there are 2\(\pi\) rad in a full circle. This is a similar quantity with multiple occurences of \pi
to test a particular template used for HTML output. It is not meant to make any sense: 21\(\pi\)45\(\pi\)234\(\pi\)890 rad.For a full list of the allowed units and prefixes, see
pretext-units.xsl
. If you have a need for more units, they need to be added to pretext-units.xsl
in the section that deals with units which are not part of siunitx
by default. Note that the mag
element should come first, followed by the unit
element, followed by the per
element.