     // Warmup trial.
     trial();
 
-    std::size_t const trials
+    uint64_t const trials
       = trial.is_baseline() ? baseline_trials : regular_trials;
 
     std::vector<double> times;
     times.reserve(trials);
 
-    for (std::size_t t = 0; t < trials; ++t)
+    for (uint64_t t = 0; t < trials; ++t)
     {
       // Generate random input for next trial. 
       trial.setup(elements);

template <
    template <typename> class Test
  , typename                  ElementMetaType
  , std::size_t               Elements
  , std::size_t               BaselineTrials
  , std::size_t               RegularTrials
>
char const* const
experiment_driver<

///////////////////////////////////////////////////////////////////////////////

template <
    uint64_t Elements
  , uint64_t BaselineTrials
  , uint64_t RegularTrials
>
void run_and_print_core_primitives_experiments()
{
