--- Peder Holt <peder.holt@gmail.com> wrote:
To test the accuracy, I have tested it against Cromwell's sine-implementation (which by the way had a bug: Instead of 1-(angle*angle*/((2*i+2)*(2*i+3))*next_term it had (angle*angle*/((2*i+2)*(2*i+3))*next_term-1)
Muy bien, jefe, I will fix it for my next version.
There are four ways to construct a double: integral_to_double<mpl::int_<-355> > or integral_c_to_double<int,-355>::type
string_c_to_double<3,'.',1,4,1,5,9,2,6,5,3,5,8,9,7,9,3,2,3,8,4,6,2,6,4,3,3,8,3,2,7,9>
typedef
BOOST_DOUBLE(3.141592653589793238462643383279502884197169399375105820974944592)
pi; double_<mantissa<0x6487ed51,0x085a3000>,1,0> <-Equivalent of pi.
The algorithm behind string_c_to_double is not very efficient, so if anyone has a better idea for an implementation, feel free to contribute :)
string_c_to_double looks interesting, perhaps I can use the underlying mechanisms to implement big_integral (which currently takes too many resources to compile, so "not very efficent" is better in this case).
On the upside, this implementation uses a 61 bit mantissa, so it is possible to utilize the full mantissa without rounding when calculating e.g. sine. This is done using
boost::metamath::detail::plus_double_double<a,b>::type
boost::metamath::detail::times_double_double<a,b>::type
boost::metamath::detail::divides_double_double<a,b>::type Would an MPL inner namespace be more appropriate? Say, boost::mpl::aux::double::plus<>, boost::mpl::aux::double::times, etc.
The user should then deal with rounding before returning the final value: boost::metamath::detail::round<a>::type; or boost::metamath::detail::cutoff<a>::type; if no rounding is wanted.
Would it be more practical to pass two arguments to each metafunction? Users don't always want to round to the nearest integer; e.g. for trigonometric apps one might need to round to the nearest PI/8.
The source is available from the vault: http://boost-sandbox.sourceforge.net/vault/ <metamath.zip>
Cool, I'll study it further when I get the chance. Cromwell D. Enage ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs