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Re: Free42 - A Complex glitch? - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: Re: Free42 - A Complex glitch? (/thread-197264.html) |
Re: Free42 - A Complex glitch? - fhub - 09-22-2011 Quote:Hi THomas, can we expect a fix for this new bug, too? ;-)
Franz
Re: Free42 - A Complex glitch? - hugh steers - 09-22-2011 Hi, i'm just going to add another twist here. a bit late to the party, but i just tried the same acos(cos((200+200i)) on my reckon calculator. unfortunately it fails too. i am using an equally lame formula. i changed my acos(z) routine to use this:
acos(z) = -2i*log(sqrt((1+z)/2) + i*sqrt((1-z)/2)) it's from Kahan 1987, but i dont have the paper with the theory behind it. anyhow it works fine for this problem. i've changed reckon to use this way of calculating acos and asin.
> acos(cos(200+200i)) my 2c.
-- hugh.
Re: Free42 - A Complex glitch? - Ángel Martin - 09-22-2011 looks like my test case is getting a lot of attention :-) thanks for the formulas, it's an interesting approach.
Best, Re: Free42 - A Complex glitch? - Thomas Okken - 09-22-2011 I'll fix the complex ASIN and ASINH in the Binary version this weekend, and check if any of the other code that uses atan2() in the Binary version is affected by the "negative zero" issue. The "negative zero" thing only affects the Binary versions, so that doesn't affect my iPhone and Android builds, which are Decimal only. (Is anyone aware of problems with Free42's complex ACOS/ACOSH?)
Edited: 23 Sept 2011, 2:08 a.m.
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