379     using array_t = std::array<double, 2>;  in TEST()  typedef
381     std::vector<array_t> arrays(TEST_SIZE);  in TEST()
383     Statistics<array_t, array_t, array_t, double,  in TEST()
384                double, innerProduct_scalar<array_t>> stat_array;  in TEST()
385     Statistics<array_t, array_t, array_t, double,  in TEST()
386                array_covariance_ut_t, outerProduct_UT_array<array_t>> stat_array_ut;  in TEST()
447     using array_t = std::array<double, 2>;  in TEST()  typedef
448     array_t data{0.0, 1.5};  in TEST()
452         data = data + array_t{0.1, 0.2};  in TEST()
496     using array_t = std::array<double, 2>;  in TEST()  typedef
502     array_t incr{1. / ELEMENTS, 1. / ELEMENTS};  in TEST()
506     std::vector<array_t> noise(ELEMENTS);  in TEST()
518             array_t data = j * incr + noise[j] * stddev;  in TEST()