HP41: accuracy of 13digit routines

09032015, 01:33 PM
(This post was last modified: 09032015 02:47 PM by Ángel Martin.)
Post: #11




RE: HP41: accuracy of 13digit routines
(09032015 12:36 PM)Dieter Wrote:(09032015 06:22 AM)Ángel Martin Wrote: the X! on the 15C is the gamma function, right? So there you also have it to test for the accuracy to the 10th decimal digit. Great! (09032015 12:36 PM)Dieter Wrote: BTW, have you read the recent thread on Spouge's Gamma approximation in the HP41 software library? Les and I have been talking about an improved Lanczos method, and I posted a set of coefficents resulting in a relative error less than 2 E–11 up to Gamma(71), and this with even two terms less than the current Sandmath implementation. I need to check how that one will pan out  how many coefficients are you using in the inproved version? I haven't really looked into the details yet... but if it's equal or better than the current implementation (up to 10 digits, remember...) then it'll be worth replacing it with the new set. PS. ok there are 4 coefficients instead of 7  so far so good, but what about the rest of the formula? c replaces the arbitrary "5" value, but does the rest remain unchanged?? Pls. let me know which of the formulas on Viktor's page would be the applicable one for the new coefficient set: http://www.rskey.org/CMS/index.php/thelibrary/11 ÁM "To live or die by your own sword one must first learn to wield it aptly." 

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