NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/comp/lang/fortran/4427

Text File | 1992-11-23 | 901 b | 27 lines

Newsgroups: comp.lang.fortran
Path: sparky!uunet!destroyer!cs.ubc.ca!newsserver.sfu.ca!sfu.ca!dedmunds
From: [e-mail] (Darran Edmundson)
Subject: a question on ATAN function
Message-ID: <[e-mail]>
Sender: [e-mail]
Organization: Simon Fraser University, Burnaby, B.C., Canada
Date: Mon, 23 Nov 1992 19:50:28 GMT
Lines: 16

I'd like to pose a neophyte question on using the arctan function to
calculate the phase angle of a complex variable (i.e. \theta = atan(v/u)
where u and v are the real and complex parts of my imaginary number
respectively).  Is it sufficient to test for u=0 (i.e. \theta = \pm \pi)
to avoid problems?  What happens if the ratio exceeds range allowed
for doubles or reals?  How do you avoid this problem?

(Now that I think about it, is it better to use arcsin or arccos?)

Thanks for you help.

--

Darran Edmundson
[e-mail]