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I guess I must be missing something, but as I understand it the factors in that table are simply the numerical equivalent used when the name is given in a prefix attribute. e.g. 1 milli metre is equivalent to 1*10^-3 metres (so prefix="-3").


Andrew Miller wrote:

In addition to the XSD(which I am making progress on), and the definition of
the
independent variable, we will probably also need to fix the table of "prefix"
values before CellML 1.1 is finalised...

The prefix attribute can be used to indicate a scale for the referenced units.
It is included primarily for the convenience of modellers who want to define
units that differ from another units definition only by an SI scale factor.
Its
value must be from the standard set of CellML prefix names given in Table 3 or
be an integer, in which case the units are pre-multiplied by 10 to the power
of
this number. The default value of the prefix attribute is "0" (the referenced
units are scaled by a factor of one).
name factor name factor
yotta 10^24 deci 10^-1
zetta 10^21 centi 10^-2
exa 10^18 milli 10^-3
peta 10^15 micro 10^-6
tera 10^12 nano 10^-9
giga 10^9 pico 10^-12
mega 10^6 femto 10^-15
kilo 10^3 atto 10^-18
hecto 10^2 zepto 10^-21
deka 10^1 yocto 10^-24
Table 3 The set of names that may be used in the prefix attribute on a <unit>
element and the corresponding scale factors that will pre-multiply the unit.

Note that the factors are the wrong way around -- e.g. to convert from milli
to
the SI unit, you should multiply by 10^3 not 10^-3.

Best regards,
Andrew


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• [cellml-discussion] Another thing to fix before CellML 1.1 is finalised, Andrew Miller, 03/05/2005
  • Re: [cellml-discussion] Another thing to fix before CellML 1.1 is finalised, David Nickerson, 03/07/2005
    • Re: [cellml-discussion] Another thing to fix before CellML 1.1 is finalised, Andrew Miller, 03/07/2005
      • Re: [cellml-discussion] Another thing to fix before CellML 1.1 is finalised, Warren Hedley, 03/08/2005

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