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Double sorting of exponents removed

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This commit is contained in:
Mateusz Pusz
2019-07-18 10:01:42 +02:00
parent f80fcad920
commit 7cbeb35e17
3 changed files with 4 additions and 21 deletions
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13
doc/DESIGN.md
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@ -179,17 +179,6 @@ contained base dimensions. Beside providing ordering to base dimensions it also
- aggregate two arguments of the same base dimension but different exponents
- eliminate two arguments of the same base dimension and with opposite equal exponents
Additionally, it would be good if the final type produced by `make_dimension_t` would be easy to
understand for the user. For example we may decide to order base dimensions with decreasing order of
their exponents. That is why second sorting of a type list may be required. For example:
```cpp
template<Exponent... Es>
struct make_dimension {
using type = mp::type_list_sort_t<detail::dim_consolidate_t<mp::type_list_sort_t<dimension<Es...>, exp_dim_id_less>>, exp_greater_equal>;
};
```
#### `merge_dimension`
@ -218,7 +207,7 @@ Example implementation of `merge_dimension` may look like:
```cpp
template<Dimension D1, Dimension D2>
struct merge_dimension {
using type = mp::type_list_sort_t<detail::dim_consolidate_t<mp::type_list_merge_sorted_t<D1, D2, exp_dim_id_less>>, exp_greater_equal>;
using type = detail::dim_consolidate_t<mp::type_list_merge_sorted_t<D1, D2, exp_dim_id_less>>;
};
```

10
src/include/units/dimension.h
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@ -65,12 +65,6 @@ namespace units {
struct exp_dim_id_less : dim_id_less<typename E1::dimension, typename E2::dimension> {
};
// exp_dim_id_less
template<Exponent E1, Exponent E2>
struct exp_greater_equal : std::bool_constant<(E1::value >= E2::value)> {
};
// exp_invert
template<Exponent E>
@ -154,7 +148,7 @@ namespace units {
template<Exponent... Es>
struct make_dimension {
using type = type_list_sort<detail::dim_consolidate_t<type_list_sort<dimension<Es...>, exp_dim_id_less>>, exp_greater_equal>;
using type = detail::dim_consolidate_t<type_list_sort<dimension<Es...>, exp_dim_id_less>>;
};
template<Exponent... Es>
@ -162,7 +156,7 @@ namespace units {
template<Dimension D1, Dimension D2>
struct merge_dimension {
using type = type_list_sort<detail::dim_consolidate_t<type_list_merge_sorted<D1, D2, exp_dim_id_less>>, exp_greater_equal>;
using type = detail::dim_consolidate_t<type_list_merge_sorted<D1, D2, exp_dim_id_less>>;
};
template<Dimension D1, Dimension D2>

2
test/unit_test/test_dimension.cpp
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@ -59,7 +59,7 @@ namespace {
static_assert(std::is_same_v<dimension_multiply_t<dimension<e<0, 1>, e<1, 1>, e<2, 1>>, dimension<e<3, 1>>>,
dimension<e<0, 1>, e<1, 1>, e<2, 1>, e<3, 1>>>);
static_assert(std::is_same_v<dimension_multiply_t<dimension<e<0, 1>, e<1, 1>, e<2, 1>>, dimension<e<1, 1>>>,
dimension<e<1, 2>, e<0, 1>, e<2, 1>>>);
dimension<e<0, 1>, e<1, 2>, e<2, 1>>>);
static_assert(std::is_same_v<dimension_multiply_t<dimension<e<0, 1>, e<1, 1>, e<2, 1>>, dimension<e<1, -1>>>,
dimension<e<0, 1>, e<2, 1>>>);