从笛卡尔坐标转换为对数极坐标
我想将笛卡尔系统中给出的一些点坐标转换为对数极坐标笛卡尔系统。
但是，我不确定如何很好地执行 atan 操作。
目前，我正在这样做，这看起来很丑陋。
Xlp = zeros(n, 2);
Xlp(:, 1) = log(sqrt(Xt(:, 1).^2 + Xt(:, 2).^2));
sel = Xlp(:, 1) >= 0 && Xlp(:, 2) >= 0;
Xlp(sel, 2) = atan(Xt(sel, 2) / Xt(sel, 1));
sel = Xlp(:, 1) >= 0 && Xlp(:, 2) < 0;
Xlp(sel, 2) = repmat(2*pi, size(sel), 1) + atan(Xt(sel, 2) / Xt(sel, 1));
sel = Xlp(:, 1) < 0 && Xlp(:, 2) >= 0;
Xlp(sel, 2) = repmat(pi, size(sel), 1) + atan(Xt(sel, 2) / Xt(sel, 1));
sel = Xlp(:, 1) < 0 && Xlp(:, 2) < 0;
Xlp(sel, 2) = repmat(pi, size(sel), 1) + atan(Xt(sel, 2) / Xt(sel, 1));
输入点位于 Xt 中，第一列是 X 坐标值，第二列是 Y 坐标值。 Xlp 包含对数极坐标，第一列对应于距离，第二列对应于角度。
I want to convert some point coordinates which are given in a cartesian system to a log-polar cartesian system.
However, I'm not sure how to perform the atan operation nicely.
Currently, I'm doing it as follows, which seems to be pretty ugly.
Xlp = zeros(n, 2);
Xlp(:, 1) = log(sqrt(Xt(:, 1).^2 + Xt(:, 2).^2));
sel = Xlp(:, 1) >= 0 && Xlp(:, 2) >= 0;
Xlp(sel, 2) = atan(Xt(sel, 2) / Xt(sel, 1));
sel = Xlp(:, 1) >= 0 && Xlp(:, 2) < 0;
Xlp(sel, 2) = repmat(2*pi, size(sel), 1) + atan(Xt(sel, 2) / Xt(sel, 1));
sel = Xlp(:, 1) < 0 && Xlp(:, 2) >= 0;
Xlp(sel, 2) = repmat(pi, size(sel), 1) + atan(Xt(sel, 2) / Xt(sel, 1));
sel = Xlp(:, 1) < 0 && Xlp(:, 2) < 0;
Xlp(sel, 2) = repmat(pi, size(sel), 1) + atan(Xt(sel, 2) / Xt(sel, 1));
Input points are in Xt with the first column being the X coordinate values and the second column being the Y coordinate values. Xlp contains the logpolar coordinates given as the first column corresponding to the distance and the second column corresponding to the angle.
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我愿意吗
？
I'd do
?
使用 atan2() 为您完成所有这些艰苦的工作。
Use atan2() to do all this hard work for you.