title: LAPACK/BLAS versus simple "for" loops
body: <p>I want to migrate a piece of code that involves a number of vector and matrix calculations to C or C++, the objective being to speed up the code as much as possible.</p>
  
  <p>Are linear algebra calculations with <code>for</code> loops in C code as fast as calculations using LAPACK/BLAS, or there is some unique speedup from using those libraries?</p>
  
  <p>In other words, could simple C code (using <code>for</code> loops and the like) perform linear algebra calculations as fast as code that utilizes LAPACK/BLAS?</p>