* UNIT TEST
  NEARLY DONE * test operations
  * test vector_space_algebra, maybe with some proto lib
  NEARLY DONE * test copying
    * include controlled_error_stepper_fsal
    * include dense_output_explicit
    * inlcude dense_output_controlled_explicit_fsal
  * test gsl
  * test explicit stepper with ranges
  * split check_concepts into check_stepper_concept, check_error_stepper_concept, check_controlled_stepper_concept
  * include test/thrust in jam system, use system from
  * ranges and the integrate functions
  * symplectic intergrators and ranges
  * adams_moulton complete
  * adams_bashforth_moulton complete
* DOCUMENTATION
  * include links to the source of the examples
  * use classical citations, via []
* GENERAL:
  * check if everywhere static_cast< value_type > is used
  * check header guards
  * check copyright note
  * documente every file in the preamble
  * check once more, if all contructor, destructors and assign-operators are present
* Factory functions for steppers, controlled_steppers, error_checker und dense_output_stepper
* same interface for implicit_euler and rosenbrock4
  * implicit euler, include dfdt
* Controlled stepper and dense output stepper
  * check if rosenbrock controller and controlled_stepper can both be used with the explicit steppers
  * check if rosenbrock4_dense_output and dense_output_explicit can be used unified to one dense output stepper
  * rename controlled_stepper to a more specific name
* skript for setting the include defines according to the position in file system an writing a general copyright comment at the beginning
* Documentation
* Tutorials

* Strategy for values which initializing, resizing etc. if some values change, for example:
  * dxdt in explicit fsal stepper, if size changes or if time is not appropriate.
  * the buffer in adams bashforth if dt changes oder the size of x.



* UNIT TEST Requirements (NEW):
  * test stepper concepts
    * top level concepts (stepper, error_stepper, controlled_stepper, dense_output_stepper)
    * adjust_size, algebras, various versions of do_step, try_step, ... 
  * test resizing and resize functionality
  * test copying (copy ctor, assign operator)
  * stepper results ?
  * stepper with ranges
  * stepper with units
 

TO BE DISCUSSED:

* Concept Jungle - describe problem, find solution (algebra, do_steps)
* boost range enhancement: copy, construct, descruct, resize, adjust_size ...
* boost::ref for system functions
* algebras as Proto expression and as instances



DONE:

OK * INTEGRATE FUNCTIONS
  OK * check forwarding problem, ranges
  OK * check where exactly the observer will be called (before, after each step?)
  OK * functions without obversers
  OK * integrate without stepper , intelligent choice of the stepper
  OK * check function signatures
  OK * what to throw?
  OK * check lambdas, lambda is broken
OK * move error_checker into controlled_stepper
OK * finishing change of controlled_stepper to units
OK * dense output for rosenbrock
OK * symplecit_stepper
  OK * find an appropriate name, (symplectic stroemer nystroem)
  OK * check is the coefficients are named good
  OK * include do_step( system , q , p , t , dt )
OK * rename error_checker_standard to default_error_checker
OK * check the order of arguments in the observer in integrate functions and initialize in dense_output_stepper
OK * decrease complexity:
  LATER * remove construct, destruct, copy ?
  OK * remove the overloads solving the forwarding problem. boost::range can not be used then anymore
OK * file cleanup
   OK * split resizing and copy/destruct/construct in different files
   OK * subfolder algebra, operations, util
OK * change standard_operations::rel_error in order to word with units and test it
OK * include implicit euler
  OK * call via std::pair< deriv , jacobi >
  OK * resizing
OK * operations that fit units
OK * operations that fit result_of
OK * change stepper to stepper_units
OK * change error_stepper to error_stepper_units
OK * change dense_output to units
  OK * roll out dense_output_explicit_euler::calc_state() to explicit_euler::dense_output()
  OK * roll out dense_output_dopri5::calc_state() to explicit_error_dopri5::dense_output()
  OK * create dense_output_explicit
  OK * create dense_output_explicit_controlled_fsal
OK * change resizing concept, in order to word within the implicit steppers
OK * in all tests and regression test do not include odeint.hpp, only include the headers which are really needed
OK * start new doc or cleanup the old project
OK * unit test
  OK * test standard_algebra
  OK * test fusion_algebra
  OK * test, if copy construct of stepper_base is called when explicit_euler is used
  OK * test units with dense output
OK * include rosenbrock4 in trunk
* ranges:
  OK * test ranges in symplectic_rkn_stepper
  OK * dense_output
  OK * explicit_stepper_and_error_stepper_fsal_base
  OK * controlled_error_stepper
  OK * check comments (spelling and if the comment is true, in some versions dxdt is already const) 
  OK * check names of the impl functions