On Mon, 22 Aug 2011 22:05:13 +0200, Larry Evans <cppljevans@suddenlink.net> wrote:
On 08/22/11 13:01, Mario Mulansky wrote: [snip]
Please visit the docs to find out more about the features and abilities of odeint: http://headmyshoulder.github.com/odeint-v2/doc/index.html [snip] Here:
http://headmyshoulder.github.com/odeint-v2/doc/boost_sandbox_numeric_odeint/...
the number 14 appears with no explanation of why 14 was chosen instead of say 20 or 50. Instead of 14, it would be better if there were some macro, like mpl's BOOST_MPL_LIMIT_VECTOR_SIZE:
First, the description of the algebra/operations is very brief, lots of details are still missing there. The number 14 is induced by the maximum number of stages used in a stepper (here in the runge_kutta78 stepper). Also, I up to now never encountered an algorithm which requires more stages so I currently don't see a reason to increase the number. However, I generally agree that it might be better to implement the operations by using Macros. But opposing to the BOOST_MPL_LIMIT_VECTOR_SIZE there is absolutely no point in giving the user the possibility to change the, say, ODEINT_OPERATIONS_COUNT as it is strictly defined by the implemented algorithms. For this reason switching to a macro-ized version does not have priority for us at the moment as we currently don't see any benefit, except elegance maybe.
http://www.boost.org/doc/libs/1_47_0/libs/mpl/doc/refmanual/limit-vector-siz...
There's also a typo on state_algebra_operations.html:
Constrcuts a Scale object
Will be corrected, thanks.
Also, couldn't:
algebra.for_eachN( y, x1, x2, ... xN-1)
be replaced by generating overloaded algebra.for_each's? Similarly, couldn't Operations::scale_sumN< Value1, Value2, ..., ValueN> done like the way fusion::vector is done? This might make it easier, in the future, to convert to variadic templates. OTOH, why not try variadic templates now?
Switching to an overloaded for_each would be no problem at all. But I do actually like the for_eachN version because the compiler tells you if you accidentally forget an argument. A bug rather difficult to identify if just another overload kicks in. As said before, revisiting the Operations is something I want to look into at some point, but for now I don't think it's worth the effort. As Karsten said, odeint-v2 is and will stay C++03, we have an c++11 version in mind where operations and algebra will surely look more sophisticated. Thanks for your comments! Best, Mario
-regards, Larry