Difference between revisions of "Sinc function"

From HaskellWiki
Jump to navigation Jump to search
m (Mathify 0/0)
(Category:Mathematics)
Line 1: Line 1:
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>
+
<haskell>
 
epsilon :: RealFloat a => a
 
epsilon :: RealFloat a => a
 
epsilon = encodeFloat 1 (fromIntegral $ 1-floatDigits epsilon)
 
epsilon = encodeFloat 1 (fromIntegral $ 1-floatDigits epsilon)
Line 11: Line 11:
 
where
 
where
 
taylor_n_bound = sqrt $ sqrt epsilon
 
taylor_n_bound = sqrt $ sqrt epsilon
</pre>
+
</haskell>
  +
  +
[[Category:Mathematics]]

Revision as of 16:34, 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 | (abs x) >= taylor_n_bound = (sin x)/x
       | otherwise = 1 - (x^2/6) + (x^4/120)
 where
  taylor_n_bound = sqrt $ sqrt epsilon