Inconsistency of angle function in finding angle of vectors
5 ビュー (過去 30 日間)
古いコメントを表示
Typing the command angle(1+i) yields an angle of 45 degrees, but typing angle(-1-2i) yields -2.0344. Why is the angle being measured clockwise from the x axis in one case and and counterclockwise in the other? Is there any more consistent way to find the angle of vectors, either measured clockwise or counterclockwise?
0 件のコメント
採用された回答
the cyclist
2021 年 4 月 12 日
I would not characterize this as an inconsistency, so much as a convention to report the value in the range [-pi,pi], rather than the [0,2pi] that you expected. (I feel obligated to point out that this is quite explicit in the documentation.)
Regardless of your opinion on that, all you need to do is calculate the result modulus 2pi, to get what you want
mod(angle(1+i),2*pi)
mod(angle(-2-i),2*pi)
0 件のコメント
その他の回答 (1 件)
Steven Lord
2021 年 4 月 12 日
Typing the command angle(1+i) yields an angle of 45 degrees,
No it doesn't. It returns the equivalent angle in radians, however.
A1 = angle(1+1i)
A2 = deg2rad(45)
abs(A2-A1)
but typing angle(-1-2i) yields -2.0344.
A3 = angle(-1-2i)
Correct.
Why is the angle being measured clockwise from the x axis in one case and and counterclockwise in the other?
"theta = angle(z) returns the phase angle in the interval [-π,π] for each element of a complex array z. The angles in theta are such that z = abs(z).*exp(i*theta)."
If you want the angles to be in the interval [0, π] instead add the negative angle to 2*pi.
A3pos = 2*pi+A3
theAngles = rad2deg([A3; A3pos])
These angles are:
diff(theAngles)
360 degrees apart.
0 件のコメント
参考
カテゴリ
Help Center および File Exchange で Line Plots についてさらに検索
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!