title: Identify significant change on a slope
body: <p>I am trying to find a point where a <em>big change</em> happens on a slope.</p>
  
  <p>Tried to use <code>ecp::e.divisive()</code> function with different settings and couldn't make it identify the change the way I need.</p>
  
  <p>Below code and plot should illustrate more. Grey lines are cutoffs coming from <code>ecp</code> package, and I am trying to it to plot blue line (which is at the moment plotted manually).</p>
  
  <p>Please advise if there are better packages for this task.</p>
  
  <pre><code>library("ecp")
  #get cutoff points
  ecpOutput &lt;- e.divisive(x, k=1)
  ecpOutput$estimates
  
  #plot 
  plot(x, bty = "n")
  abline(h = 0, lty = "dashed", col = "grey")
  
  #add ecp estimates
  abline(v = ecpOutput$estimates, col = "grey", lty = 2)
  
  #ideal line, doesn't have to be exact, anything around this line is OK
  abline(v = 384, col = "blue", lty = 2)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/dsa2A.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dsa2A.jpg" alt="enter image description here"></a></p>
  
  <p><strong>Data:</strong> x is a sorted 1 column matrix (required structure by <code>ecp</code>).</p>
  
  <pre><code>x &lt;- structure(c(-27.0409169663486, -26.129156710088, -24.7600585044449, 
  -24.3953228174759, -24.1577613311647, -23.5016667274094, -20.6947912955816, 
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  -6.37631310536975, -6.35766817597632, -6.33004629281548, -6.32243131413274, 
  -6.31465060236999, -6.30957529705468, -6.20042487075657, -6.19852760812695, 
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  0.034746934017077, 0.0493559949320308, 0.192914632754347, 0.218667918037225, 
  0.245737147003821, 0.247527541956785, 0.333222558419853, 0.557256844844099, 
  0.669063496448389, 0.720955292473698, 0.767660102407662, 0.878291398784322, 
  0.946178076488395, 0.946467111772845, 1.11121506783806, 1.22835778244999, 
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  1.35802473804966, 1.48779920673317, 1.6470804669896, 1.75657725379367, 
  1.91434060426954, 3.12793082392592, 4.05818631097523, 5.87762107232264, 
  7.87360999893622, 54.7844606150857), .Dim = c(389L, 1L))
  </code></pre>