# Difference between revisions of "Sinc function"

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BrettGiles (talk | contribs) m (Mathify 0/0) |
(Category:Mathematics) |
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− | The sinc function, <math>\frac{sin(x)}{x}</math>, is a useful function that is a little tricky to implement because it becomes <math>\frac{0}{0}</math> as x approaches <math>0</math>. Here is an implementation taken from the [http://www.boost.org/boost/math/special_functions/sinc.hpp Boost] library. |
+ | The sinc function, <math>\frac{\sin(x)}{x}</math>, is a useful function that is a little tricky to implement because it becomes <math>\frac{0}{0}</math> as x approaches <math>0</math>. Here is an implementation taken from the [http://www.boost.org/boost/math/special_functions/sinc.hpp Boost] library. |

− | <pre> |
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+ | <haskell> |
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epsilon :: RealFloat a => a |
epsilon :: RealFloat a => a |
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epsilon = encodeFloat 1 (fromIntegral $ 1-floatDigits epsilon) |
epsilon = encodeFloat 1 (fromIntegral $ 1-floatDigits epsilon) |
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{- 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 -} |
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sinc :: (RealFloat a) => a -> a |
sinc :: (RealFloat a) => a -> a |
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⚫ | |||

+ | sinc x = |
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⚫ | |||

⚫ | |||

+ | then sin x / x |
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⚫ | |||

where |
where |
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taylor_n_bound = sqrt $ sqrt epsilon |
taylor_n_bound = sqrt $ sqrt epsilon |
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− | </ |
+ | </haskell> |

+ | |||

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