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https://github.com/mpusz/mp-units.git
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Mateusz Pusz
703235d1d4
Replace the `disable_vector`/`disable_tensor` opt-outs with intrinsic, adapter-overridable traits and split representation classification into two tiers. - `customization_points.h` now owns the customizable surface: the `real`/`imag`/ `modulus` CPOs plus the `numeric_field` (field axis) and `tensor_order` (order axis) traits. Adapters specialize these; the derived concepts stay with the rest of the concept model in `representation_concepts.h`. - `numeric_field` is the single source of truth for the field axis (default: `real()`/`imag()` API detection). Field matching is exact and disjoint - a real quantity needs a real representation and a complex one a complex representation. - `tensor_order` is detected structurally (two-index access -> 2, one-index -> 1, otherwise 0) and overridable. Order matching is rank-ordered: a lower-order representation fills a higher-order slot. - Character concepts (`Real`/`Complex`, rank-ordered `Scalar`/`Vector`/`Tensor`) carry no representation-validity, so in V3 they can also classify a quantity by its character. The `*Representation` concepts are `NotQuantity`-first + character + `UnitMagnitudeScalable`; leading with `NotQuantity` rejects a quantity before its operators are instantiated, avoiding a constraint-satisfaction cycle. - Eigen/Blaze adapters declare `numeric_field` from their element type (they expose `real()`/`imag()` on real types too, which the API default would misread as complex). - Rename `MagnitudeScalable` -> `UnitMagnitudeScalable` and `UsesMagnitudeAwareScaling` -> `UsesUnitMagnitudeAwareScaling` to disambiguate scaling by a `unit_magnitude` from the value/L2 magnitude (the `magnitude` CPO). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
93 lines
4.2 KiB
C++
93 lines
4.2 KiB
C++
// The MIT License (MIT)
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//
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// Copyright (c) 2018 Mateusz Pusz
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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#include <mp-units/bits/fixed_point.h>
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#include <mp-units/compat_macros.h>
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#include <mp-units/framework.h>
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#include <mp-units/systems/angular.h>
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#ifdef MP_UNITS_IMPORT_STD
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import std;
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#else
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#include <cstdint>
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#include <type_traits>
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#endif
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using namespace mp_units;
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namespace {
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// min_width_uint_t selects the narrowest standard unsigned type that holds N bits
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static_assert(std::is_same_v<detail::min_width_uint_t<1>, std::uint8_t>);
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static_assert(std::is_same_v<detail::min_width_uint_t<7>, std::uint8_t>);
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static_assert(std::is_same_v<detail::min_width_uint_t<8>, std::uint8_t>);
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static_assert(std::is_same_v<detail::min_width_uint_t<9>, std::uint16_t>);
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static_assert(std::is_same_v<detail::min_width_uint_t<31>, std::uint32_t>);
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static_assert(std::is_same_v<detail::min_width_uint_t<32>, std::uint32_t>);
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static_assert(std::is_same_v<detail::min_width_uint_t<33>, std::uint64_t>);
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// scale<To>(M{}, value) — integer-to-integer path (exact arithmetic, no floating point)
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// integral factor: exact integer multiply
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static_assert(scale<int>(mag<1000>, 5) == 5000);
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static_assert(scale<long>(mag<60>, 2l) == 120l);
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// integral inverse: exact integer divide
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static_assert(scale<int>(mag_ratio<1, 1000>, 5000) == 5);
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static_assert(scale<int>(mag_ratio<1, 60>, 120) == 2);
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// rational M (3/2 * 4 == 6): exact widened integer arithmetic (int64_t for int)
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static_assert(scale<int>(mag_ratio<3, 2>, 4) == 6);
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// (1/3 * 9 == 3)
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static_assert(scale<int>(mag_ratio<1, 3>, 9) == 3);
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// identity
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static_assert(scale<int>(mag<1>, 42) == 42);
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// floating-point path
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static_assert(scale<double>(mag_ratio<1, 2>, 1.0) == 0.5);
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static_assert(scale<float>(mag<3>, 1.0f) == 3.0f);
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// UnitMagnitudeScalable concept
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static_assert(detail::UnitMagnitudeScalable<int>);
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static_assert(detail::UnitMagnitudeScalable<long>);
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static_assert(detail::UnitMagnitudeScalable<double>);
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static_assert(detail::UnitMagnitudeScalable<float>);
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// Irrational magnitude conversions with integer representation require explicit value_cast.
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// deg = (π/180) rad — the conversion factor is irrational, so every integer result is approximate.
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//
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// Positive: value_cast compiles and produces the expected truncated integer result.
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static_assert(value_cast<angular::degree>(1 * angular::radian).numerical_value_in(angular::degree) == 57);
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static_assert(value_cast<angular::radian>(180 * angular::degree).numerical_value_in(angular::radian) == 3);
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// Negative: implicit conversion is blocked at compile time to prevent accidental precision loss.
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static_assert(!std::is_convertible_v<quantity<angular::radian, int>, quantity<angular::degree, int>>);
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static_assert(!std::is_convertible_v<quantity<angular::degree, int>, quantity<angular::radian, int>>);
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// Large-value safety: deg -> grad uses factor 10/9. Being a pure rational, the
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// computation uses exact 128-bit integer arithmetic — correct on all platforms,
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// including ARM / Apple Silicon where long double == double (64-bit mantissa).
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static_assert(value_cast<angular::gradian>(std::int64_t{1'000'000'000'000'000'000} * angular::degree)
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.numerical_value_in(angular::gradian) == std::int64_t{1'111'111'111'111'111'111});
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} // namespace
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