title: GSL: Random number generator should be unique in one program
body: <p>I am using GNU Scientific Library to generate random number. <a href="https://www.gnu.org/software/gsl/doc/html/rng.html" rel="nofollow noreferrer">Random Number Generation — GSL 2.7 documentation</a></p>
  <p>In general, we should get a <code>gsl_rng</code> firstly.</p>
  <pre class="lang-c prettyprint-override"><code>       const gsl_rng_type * T;
         gsl_rng * r;
       
         int i, n = 10;
       
         gsl_rng_env_setup();
       
         T = gsl_rng_default;
         r = gsl_rng_alloc (T);
  </code></pre>
  <p>But should we use <strong>one</strong> <code>gsl_rng</code> in <strong>one</strong> program?</p>