title: fast large matrix multiplication in R
body: <p>I have two matrices in R that I want to multiply:</p>
  
  <pre><code>a = matrix(rnorm(20*10000, mean=0, sd=5), 20, 10000)
  b = matrix(rnorm(20*10000, mean=0, sd=5), 20, 10000)
  t(a)%*%b
  </code></pre>
  
  <p>Given that the dimension in larger this matrix multiplication takes a lot of time, is there a specific way to make computations faster ? And are there any build in functions in R to make such multiplications faster?</p>