There are some hidden tricks I did not realize: for erf =: (1 H. 1.5)@*: * 2p_0.5&* % ^@:*: and erf2 =: ] * 2p_0.5 * [: 0.5 H.1.5 [: - *:
erf i.10 0 0.842701 0.995322 0.999978 1 1 1 1 1 1 erf2 i.10 0 0.842701 0.995322 0.999978 1 1 0.998693 _814.656 _3.47366e9 1.69158e17 erf2 blows up for big inputs. is this well known? ________________________________ From: elton wang <[email protected]> To: "[email protected]" <[email protected]> Sent: Saturday, May 11, 2013 4:36 PM Subject: Re: hypergeometric function in J Henry and Roger, Thanks very much your kindly help. Just learned that there is relation between m H. n and (n-m) H. n. The erf function erf =: (1 H. 1.5)@*: * 2p_0.5&* % ^@:*: may be rewritten to erf2 =: ] * 2p_0.5 * [: 0.5 H.1.5 [: - *:, which is the one on http://en.wikipedia.org/wiki/Confluent_hypergeometric_function. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
