title: What is the fastest way/library to calculate the rank of a matrix in C++
body: <p>What library computes the rank of a matrix the fastest? Or, is there any code out in the open that does this fairly rapidly?</p>
  
  <p>I am using Eigen3 and it seems to be slower than Python's numpy rank function. I just need this one function to be fast, absolutely nothing else matters. If you suggest a package everything but this is irrelevant, including ease of use.</p>
  
  <p>The matrices I am looking at tend to be  n by ( n choose 3) in size, the entries are 1 or 0....mostly 0's.</p>
  
  <p>Thanks.</p>
  
  <p><strong>Edit 1</strong>: the rank is over R.</p>