Create a RateMap
A RateMap is a Mapping which represents a single element of the Jacobian matrix of
another Mapping. The Mapping for which the Jacobian is required is specified when
the new RateMap is created, and is referred to as the " encapsulated Mapping"
below.
The number of inputs to a RateMap is the same as the number of inputs to its encapsulated Mapping. The number of outputs from a RateMap is always one. This one output equals the rate of change of a specified output of the encapsulated Mapping with respect to a specified input of the encapsulated Mapping (the input and output to use are specified when the RateMap is created).
A RateMap which has not been inverted does not define an inverse transformation. If a RateMap has been inverted then it will define an inverse transformation but not a forward transformation.
" printf" format specifiers identified by " %" symbols in the
normal way. " options" string contains " %" format specifiers,
then an optional list of additional arguments may follow it in order to supply
values to be substituted for these specifiers. The rules for supplying these are
identical to those for the astSet function (and for the C " printf" function). The forward transformation of the encapsulated Mapping must be defined.
Note that the component Mappings supplied are not copied by astRateMap (the new RateMap simply retains a reference to them). They may continue to be used for other purposes, but should not be deleted. If a RateMap containing a copy of its component Mappings is required, then a copy of the RateMap should be made using astCopy.
A null Object pointer (AST__NULL) will be returned if this function is invoked with the AST error status set, or if it should fail for any reason.