astInvertastInvert - Invert a Mapping

Description:
This function inverts a MappingMapping by reversing the boolean sense of its InvertInvert attribute. If this attribute is zero (the default), the Mapping will transform coordinates in the way specified when it was created. If it is non-zero, the input and output coordinates will be inter-changed so that the direction of the Mapping is reversed. This will cause it to display the inverse of its original behaviour.
Synopsis:
void astInvert( AstMapping $*$this )
Parameters:
this
Pointer to the Mapping.