title: how do i calculate correlation between corresponding columns of two matrices and not getting other correlations as output
body: <p>I have these data</p>
  
  <pre><code>&gt; a
       a    b    c
  1    1   -1    4
  2    2   -2    6
  3    3   -3    9
  4    4   -4   12
  5    5   -5    6
  
  &gt; b
       d    e    f
  1    6   -5    7
  2    7   -4    4
  3    8   -3    3
  4    9   -2    3
  5   10   -1    9
  
  &gt; cor(a,b)
             d            e             f
  a  1.0000000    1.0000000     0.1767767
  b -1.0000000    -1.000000    -0.1767767
  c  0.5050763    0.5050763    -0.6964286
  </code></pre>
  
  <p>The result I want is just:</p>
  
  <pre><code>cor(a,d) = 1
  cor(b,e) = -1
  cor(c,f) = -0.6964286
  </code></pre>