# Difference between revisions of "Sinc function"

From HaskellWiki

(Category:Mathematics) |
(Category:Mathematics) |
||

Line 7: | Line 7: | ||

{- Boosted from Boost http://www.boost.org/boost/math/special_functions/sinc.hpp -} | {- Boosted from Boost http://www.boost.org/boost/math/special_functions/sinc.hpp -} | ||

sinc :: (RealFloat a) => a -> a | sinc :: (RealFloat a) => a -> a | ||

− | sinc x | + | sinc x = |

− | + | if abs x >= taylor_n_bound | |

+ | then sin x / x | ||

+ | else 1 - x^2/6 + x^4/120 | ||

where | where | ||

taylor_n_bound = sqrt $ sqrt epsilon | taylor_n_bound = sqrt $ sqrt epsilon | ||

</haskell> | </haskell> | ||

+ | [[Category:Code]] | ||

[[Category:Mathematics]] | [[Category:Mathematics]] |

## Latest revision as of 16:35, 15 November 2006

The sinc function, , is a useful function that is a little tricky to implement because it becomes as x approaches . Here is an implementation taken from the Boost library.

```
epsilon :: RealFloat a => a
epsilon = encodeFloat 1 (fromIntegral $ 1-floatDigits epsilon)
{- Boosted from Boost http://www.boost.org/boost/math/special_functions/sinc.hpp -}
sinc :: (RealFloat a) => a -> a
sinc x =
if abs x >= taylor_n_bound
then sin x / x
else 1 - x^2/6 + x^4/120
where
taylor_n_bound = sqrt $ sqrt epsilon
```