anchor.diff:  assert(inform_succeeded(&err));
   // ce == 0.507757
   ----
  +[horizontal]
  +Header:: `inform/conditional_entropy.h`
   ****
   
   ****
  
positive.code:     double pi;
  } inform_pid_source;
  ----
  ****
  
  ****
  
negative.code:         size_t l, size_t n, size_t m, int b, size_t k,
          inform_error *err);
  ----
  [horizontal]
  Header:: `inform/separable_info.h`
  ****
  
  ****
  