#include <interval_boost_interval_type_traits.h>
Classes | |
| struct | raw_checking |
Public Types | |
| typedef boost::numeric::interval< T > | default_interval_type |
| typedef boost::numeric::interval< T, policy_type > | interval_type |
| Fast interval type, but do not have any rounding, precision or checking policies worth of mentioning. If you use this then you should know what you are doing. | |
Protected Types | |
| typedef raw_checking< T > | checking_type |
| typedef boost::numeric::interval_lib::save_state_nothing < boost::numeric::interval_lib::rounded_arith_exact < T > > | rounding_type |
| typedef boost::numeric::interval_lib::policies < rounding_type, checking_type > | policy_type |
Boost Interval Fixed Type Traits. This class provides easy type handling of the boost interval class
http://www.boost.org/libs/numeric/interval/doc/interval.htm
In computer graphics, we really do not need all the safety we get from the default interval type:
typedef ... real_type; typedef boost::numeric::interval<real_type> interval_type;
This class tweaks the policies of the interval class inorder to sacrifice everything for the need for speed.
According to
http://www.boost.org/libs/numeric/interval/doc/rounding.htm#perf
It reads:
``for fast wide intervals without any rounding nor precision, use save_state_nothing<rounded_transc_exact<T> >;''
From
http://www.boost.org/libs/numeric/interval/doc/checking.htm
We have:
``If you do not mind having undefined results when an empty interval or an interval number is produced, your best bet is to create your own policy by overloading checking_base and modifying is_nan et is_empty in order for them to always return false. It is probably the fastest checking policy available; however, it suffers from its deficient security.''
From these we have created our own rounding and checking policies. This class provides an easy way to extract the interval type for this ``speed optimized'' interval usage:
include <OpenTissue/core/math/interval/interval_boost_interval_type_traits.h>
typedef BoostIntervalTypeTraits<double>::interval_type interval_type;
....
Initial testings (see interval demo application) With .NET 2005 C++ compiler, this fast boost interval type outruns the OpenTissue interval type by a factor of 2. With gcc it seems that OpenTissue interval type is capable of beating boost. However, this fast boost type comes pretty close to the OpenTissue type on gcc.
Our (Henrik Dohlann and Kenny Erleben) recommendations: Use this fast boost interval type if you do not need the gcc-cutting edge.
Sometimes it is possible to add further optimizations by adding the following code around interval ``intensive blocks''
typedef .... interval_type; // save and initialize the rounding mode interval_type::traits_type::rounding rnd; // define the unprotected version of the interval type typedef boost::numeric::interval_lib::unprotect<interval_type>::type interval_type2;
Now one should use interval_type2 in the following computaiton block. In our test runs this ``unprotect'' tweak did not add a lot of performance to the fast boost interval type this class provides. Thus we recommend only using the ``unprotect''-way if the default boost interval type is used.
typedef raw_checking<T> OpenTissue::math::interval::BoostIntervalTypeTraits< T >::checking_type [protected] |
| typedef boost::numeric::interval<T > OpenTissue::math::interval::BoostIntervalTypeTraits< T >::default_interval_type |
| typedef boost::numeric::interval<T, policy_type > OpenTissue::math::interval::BoostIntervalTypeTraits< T >::interval_type |
Fast interval type, but do not have any rounding, precision or checking policies worth of mentioning. If you use this then you should know what you are doing.
typedef boost::numeric::interval_lib::policies< rounding_type, checking_type > OpenTissue::math::interval::BoostIntervalTypeTraits< T >::policy_type [protected] |
typedef boost::numeric::interval_lib::save_state_nothing< boost::numeric::interval_lib::rounded_arith_exact<T> > OpenTissue::math::interval::BoostIntervalTypeTraits< T >::rounding_type [protected] |
1.7.1