libSBML C API
libSBML 5.8.0 C API
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Implementation of SBML Level 3's LocalParameter construct.
LocalParameter has been introduced in SBML Level 3 to serve as the object class for parameter definitions that are intended to be local to a Reaction. Objects of class LocalParameter never appear at the Model level; they are always contained within ListOfLocalParameters lists which are in turn contained within KineticLaw objects.
Like its global Parameter counterpart, the LocalParameter object class is used to define a symbol associated with a value; this symbol can then be used in a model's mathematical formulas (and specifically, for LocalParameter, reaction rate formulas). Unlike Parameter, the LocalParameter class does not have a "constant" attribute: local parameters within reactions are always constant.
LocalParameter has one required attribute, "id", to give the parameter a unique identifier by which other parts of an SBML model definition can refer to it. A parameter can also have an optional "name" attribute of type string
. Identifiers and names must be used according to the guidelines described in the SBML specifications.
The optional attribute "value" determines the value (of type double
) assigned to the parameter. A missing value for "value" implies that the value either is unknown, or to be obtained from an external source, or determined by an initial assignment. The unit of measurement associated with the value of the parameter can be specified using the optional attribute "units". Here we only mention briefly some notable points about the possible unit choices, but readers are urged to consult the SBML specification documents for more information:
In SBML Level 3, there are no constraints on the units that can be assigned to parameters in a model; there are also no units to inherit from the enclosing Model object.
"substance"
, "time"
, "volume"
, "area"
or "length"
; or the identifier of a new unit defined in the list of unit definitions in the enclosing Model structure. There are no constraints on the units that can be chosen from these sets. There are no default units for local parameters. As with all other major SBML components, LocalParameter is derived from SBase, and the methods defined on SBase are available on LocalParameter.