Hi
the following gave me a shock:
atan(2)
[1] 1.107149
atan(2+0i)
[1] -0.4636476+0i
or, perhaps more of a gotcha:
atan(1.0001+0i)
[1] -0.7853482+0i
atan(0.+0i)
[1] 0.7853482+0i
evidently atan()'s branch cuts aren't where I thought they were.
Where do I look for documentation on this?
On Mon, 16 May 2005, Robin Hankin wrote:
Hi
the following gave me a shock:
atan(2)
[1] 1.107149
atan(2+0i)
[1] -0.4636476+0i
or, perhaps more of a gotcha:
atan(1.0001+0i)
[1] -0.7853482+0i
atan(0.+0i)
[1] 0.7853482+0i
evidently atan()'s branch cuts aren't where I thought they were.
Where do
Professor Ripley
thanks for this. Always good to know that I'm not missing any
documentation!
The source is clear; formula 4.4.39 effectively has a branch cut at
|z|=1.
A 'n' S show the standard branch cuts in their figure 4.4, which are
different (they
were the ones I was expecting).
On Mon, 16 May 2005, Robin Hankin wrote:
Professor Ripley
thanks for this. Always good to know that I'm not missing any documentation!
The source is clear; formula 4.4.39 effectively has a branch cut at |z|=1.
A 'n' S show the standard branch cuts in their figure 4.4, which are
different (they
