r - R找到曲线急剧变化的x和y值

Question

我有一个包含两列 x, y 的数据集，如下所示

  x           y
  0.5789474   0.0011382324
  1.0000000   0.0024540588
  0.8000000   0.0017039382
  0.7272727   0.0014921618
  0.8421053   0.0018399977
  0.8611111   0.0019049152
  0.3750000   0.0007843210
  0.7837838   0.0016542579
  0.7222222   0.0014784711
  0.7619048   0.0015895130
  0.7435897   0.0015372644
  0.4375000   0.0008791528
  0.8750000   0.0019537960
  0.6666667   0.0013359048
  0.8750000   0.0019537960
  0.8571429   0.0018911749
  0.6896552   0.0013931524
  1.0000000   0.0024540588
  0.9285714   0.0021543502
  0.9523810   0.0022499579

绘制这些值会生成如下图

我的目标是找到曲线的斜率或变化率最大的 x 和 y 的值。弯曲或曲线最尖锐的地方。我试过了 ，

(lead(y)-y)/(lead(x)-x)这没有用。非常感谢任何建议或意见。提前致谢。

标签： rcurvealgebra

Answer 1

很高兴见到你，野牛

在我看来，您的代码在排序后运行良好。

我不知道你为什么说(lead(y)-y)/(lead(x)-x)不起作用。见下面的代码：

x <- sort(c(
  0.5789474,1.0000000,
  0.8000000,0.7272727,
  0.8421053,0.8611111,
  0.3750000,0.7837838,
  0.7222222,0.7619048,
  0.7435897,0.4375000,
  0.8750000,0.6666667,
  0.8750000,0.8571429,
  0.6896552,1.0000000,
  0.9285714,0.9523810
))
y <- sort(c(
  0.0011382324,0.0024540588,
  0.0017039382,0.0014921618,
  0.0018399977,0.0019049152,
  0.0007843210,0.0016542579,
  0.0014784711,0.0015895130,
  0.0015372644,0.0008791528,
  0.0019537960,0.0013359048,
  0.0019537960,0.0018911749,
  0.0013931524,0.0024540588,
  0.0021543502,0.0022499579
))

> (lead(y)-y)/(lead(x)-x)
 [1] 0.001517309 0.001831632 0.002253465 0.002490271 0.002619790
 [6] 0.002710761 0.002764148 0.002852761 0.002959226 0.003063622
[11] 0.003231410 0.003403282 0.003462603 0.003519415         NaN
[16] 0.003743680 0.004015511 0.004286123         NaN          NA

x[which.max((lead(y)-y)/(lead(x)-x))]
y[which.max((lead(y)-y)/(lead(x)-x))]