如何使用MATLAB来识别图中一条线下面的点？ [英] how to identify the points below a line in a graph using MATLAB?

问题描述

运行程序后，我得到了14个 loglik 值，然后我在两行内绘制了这些值。代码如下：

  loglik = [ -  3168.7176，-4644.451，-3759.7372，-1758.1307，-4813.0647，-4147.0188， ... 
 -4330.944，-4612.9895，-3829.8987，-2687.4927，... 
 -4007.5629，-2799.527，-2747.96,4.386]; 
 aH =轴; 
 plot（aH，loglik，'r。'）;等一下; 
 threshold1 =平均（loglik）+ 1 * std（loglik）; 
 threshold2 =平均值（loglik）+ 3 * std（loglik）; 
 plot（aH，aH.XLim，[threshold2，threshold2]，'r-'）; 
 plot（aH，aH.XLim，[threshold1，threshold1]，'r-'）; 
  

现在，我要确定 threshold1 。如何才能做到这一点？

解决方案

这将区分上面的点以下 threshhold1 ：

  plot（aH，loglik（loglik> = threshold1），'r。'）; 
坚持; 
 plot（aH，loglik（loglik< threshold1），'b。'）; 
  

以上（或等于） threshhold1 是红色，下面是蓝色。

After running the program, I got 14 values of loglik, then I plotted these value within two lines. The code is below:

loglik=[-3168.7176,-4644.451,-3759.7372,-1758.1307,-4813.0647,-4147.0188,...
        -4330.944,-4612.9895,-3829.8987,-2687.4927,...
        -4007.5629,-2799.527,-2747.96,4.386];
aH = axes;
plot(aH,loglik,'r.'); hold on;
threshold1=mean(loglik)+1*std(loglik);
threshold2=mean(loglik)+3*std(loglik);
plot(aH, aH.XLim, [threshold2, threshold2], 'r-');
plot(aH, aH.XLim, [threshold1, threshold1], 'r-');

Now, I want to identify the points which are below threshold1. How can I do that?

解决方案

This will distinguish visually between the points above\below threshhold1:

plot(aH,loglik(loglik>=threshold1),'r.');
hold on;
plot(aH,loglik(loglik<threshold1),'b.');

Points above (or equal to) threshhold1 are red, and below are blue.

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