title: Probabilities in copula doesn't sum up to 1
body: <p>I am generating a matrix of probabilities from a bivariate gaussian copula with poisson marginals. I can't figure out why probabilities doesn't add to 1 but to slightly more. Here is the code:</p>
  
  <pre><code>library(copula) 
  
  cop&lt;-normalCopula(param = 0.92, dim = 2)
  mv &lt;- mvdc(cop, c("pois", "pois"),list(list(lambda = 6), list(lambda = 4)))
  
  m &lt;- matrix(NA,50,50)
  for (i in 0:49) {
    for (j in 0:49) {
      m[i+1,j+1]=dMvdc(c(i,j),mv)
    }
  }
  
  sum(m)
  [1] 1.048643
  </code></pre>
  
  <p>EDIT: It seems that this problem is present only when the <code>param</code> parameter (the correlation) is different from 0.</p>