Commit 531df959 authored by Taylor R Campbell's avatar Taylor R Campbell Committed by George Kadianakis
Browse files

Move ceil call back into the geometric sampler. 

Test exactly what the geometric sampler returns, because that's what
the downstream callers of it are going to use.

While here, also assert that the geometric sampler returns a positive
integer.  (Our geometric distribution is the one suported on {1, 2,
3, ...} that returns the number of trials before the first success,
not the one supported on {0, 1, 2, ...} that returns the number of
failures before the first success.)
parent 948856c0

src/lib/math/prob_distr.c

+1 −1
Original line number Diff line number Diff line
@@ -1308,7 +1308,7 @@ sample_geometric(uint32_t s, double p0, double p) 
  if (p >= 1)

    return 1;



  return (-x/log1p(-p));

  return ceil(-x/log1p(-p));

}



/*******************************************************************/

src/test/test_prob_distr.c

+11 −1
Original line number Diff line number Diff line
@@ -958,7 +958,17 @@ test_stochastic_geometric_impl(double p) 
    size_t C[PSI_DF] = {0};



    for (j = 0; j < NSAMPLES; j++) {

      double n_tmp = ceil(geometric_sample(p));

      double n_tmp = geometric_sample(p);



      /* Must be an integer.  (XXX -Wfloat-equal)  */

      tor_assert(ceil(n_tmp) <= n_tmp && ceil(n_tmp) >= n_tmp);



      /* Must be a positive integer.  */

      tor_assert(n_tmp >= 1);



      /* Probability of getting a value in the billions is negligible.  */

      tor_assert(n_tmp <= (double)UINT_MAX);



      unsigned n = (unsigned) n_tmp;



      if (n > PSI_DF)