title: Scipy Weibull CDF calculation
body: <p>I'm doing survival calculations in Scipy and can't get the correct values.</p>
  <p>My code:</p>
  <pre><code>x, a, c = 1000, 1.5, 5000
  
  vals = exponweib.cdf(x,a,c,loc=0,scale=1)
  </code></pre>
  <p><code>vals</code> should equal 0.085559356392783004, but I'm getting 0 instead.</p>
  <p>If I define my own function I get the right answer:</p>
  <pre><code>def weibCumDist(x,a,c):
      return 1-np.exp(-(x/c)**a)
  </code></pre>
  <p>I could just use my own function, but I'm curious as to what I'm doing wrong.</p>