Blurb::
A model with one of each block: variable, interface, and response
Description::
The single model is the simplest model type. It uses a single
\ref interface instance to map \ref variables
into \ref responses. There is no recursion in this case.

The optional \ref model-single-interface_pointer specification identifies the interface block
by cross-referencing with the \c id_interface string input from a particular interface keyword specification.
This is only necessary when the input file has multiple interface blocks, and you
wish to explicitly point to the desired block.
The same logic follows for responses and variables blocks and pointers.

Topics::	
Examples::
The example shows a minimal
specification for a single model, which is the default model when no
models are specified by the user.
\verbatim
model
  single
\endverbatim
This example does not provide any pointer strings and therefore relies
on the default behavior of constructing the model with the last
variables, interface, and responses specifications parsed.

Theory::
Faq::
See_Also::	model-surrogate, model-nested
