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libsst/Lib/Include/CML/quaternion/quaternion_comparison.h
2026-04-03 00:22:39 -05:00

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/* -*- C++ -*- ------------------------------------------------------------
Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
The Configurable Math Library (CML) is distributed under the terms of the
Boost Software License, v1.0 (see cml/LICENSE for details).
*-----------------------------------------------------------------------*/
/** @file
* @brief
*/
#ifndef quaternion_comparison_h
#define quaternion_comparison_h
#include <cml/core/cml_assert.h>
#include <cml/et/scalar_ops.h>
/* This is used below to create a more meaningful compile-time error when
* quaternion_comparison is not provided with quaternion or QuaternionExpr arguments:
*/
struct quaternion_comparison_expects_quaternion_args_error;
#define CML_QUAT_QUAT_ORDER(_order_, _op_, _OpT_) \
template< \
typename E1, class AT1, typename E2, class AT2, class O, class C > \
inline bool \
_op_ ( \
const quaternion<E1,AT1,O,C>& left, \
const quaternion<E2,AT2,O,C>& right) \
{ \
return detail::quaternion_##_order_ (left, right, _OpT_ <E1,E2>()); \
}
#define CML_QUAT_QUATXPR_ORDER(_order_, _op_, _OpT_) \
template<typename E, class AT, class O, class C, class XprT> \
inline bool \
_op_ ( \
const quaternion<E,AT,O,C>& left, \
QUATXPR_ARG_TYPE right) \
{ \
return detail::quaternion_##_order_ (left, right, \
_OpT_ <E, typename XprT::value_type>()); \
}
#define CML_QUATXPR_QUAT_ORDER(_order_, _op_, _OpT_) \
template<class XprT, typename E, class AT, class O, class C > \
inline bool \
_op_ ( \
QUATXPR_ARG_TYPE left, \
const quaternion<E,AT,O,C>& right) \
{ \
return detail::quaternion_##_order_ (left, right, \
_OpT_ <typename XprT::value_type, E>()); \
}
#define CML_QUATXPR_QUATXPR_ORDER(_order_, _op_, _OpT_) \
template<class XprT1, class XprT2> \
inline bool \
_op_ ( \
QUATXPR_ARG_TYPE_N(1) left, \
QUATXPR_ARG_TYPE_N(2) right) \
{ \
return detail::quaternion_##_order_ (left, right, \
_OpT_ < \
typename XprT1::value_type, \
typename XprT2::value_type>()); \
}
namespace cml {
namespace detail {
/** Quaternion strict weak ordering relationship.
*
* OpT must implement a strict weak order on the quaternion element type.
* operator< and operator> on integer and floating-point types are
* examples.
*/
template<typename LeftT, typename RightT, typename OpT>
inline bool
quaternion_weak_order(const LeftT& left, const RightT& right, OpT)
{
/* Shorthand: */
typedef et::ExprTraits<LeftT> left_traits;
typedef et::ExprTraits<RightT> right_traits;
/* quaternion_comparison() requires quaternion expressions: */
CML_STATIC_REQUIRE_M(
(et::QuaternionExpressions<LeftT,RightT>::is_true),
quaternion_comparison_expects_quaternion_args_error);
/* Note: parens are required here so that the preprocessor ignores the
* commas:
*/
typedef typename et::QuaternionPromote<
typename left_traits::result_type,
typename right_traits::result_type
>::type result_type;
for(ssize_t i = 0; i < result_type::array_size; ++ i) {
if(OpT().apply(
left_traits().get(left,i),
right_traits().get(right,i)
))
{
/* If weak order (a < b) is satisfied, return true: */
return true;
} else if(OpT().apply(
right_traits().get(right,i),
left_traits().get(left,i)
))
{
/* If !(b < a), then return false: */
return false;
} else {
/* Have !(a < b) && !(b < a) <=> (a >= b && b >= a) <=> (a == b).
* so need to test next element:
*/
continue;
}
}
/* XXX Can this be unrolled in any reasonable way? */
/* If we get here, then left == right: */
return false;
}
/** Quaternion total order relationship.
*
* OpT must implement a total order on the quaternion element type. operator<=
* and operator>= on integer and floating-point types are examples.
*/
template<typename LeftT, typename RightT, typename OpT>
inline bool
quaternion_total_order(const LeftT& left, const RightT& right, OpT)
{
/* Shorthand: */
typedef et::ExprTraits<LeftT> left_traits;
typedef et::ExprTraits<RightT> right_traits;
/* quaternion_comparison() requires quaternion expressions: */
CML_STATIC_REQUIRE_M(
(et::QuaternionExpressions<LeftT,RightT>::is_true),
quaternion_comparison_expects_quaternion_args_error);
/* Note: parens are required here so that the preprocessor ignores the
* commas:
*/
typedef typename et::QuaternionPromote<
typename left_traits::result_type,
typename right_traits::result_type
>::type result_type;
for(ssize_t i = 0; i < result_type::array_size; ++ i) {
/* Test total order: */
if(OpT().apply(
left_traits().get(left,i),
right_traits().get(right,i)
))
{
/* Automatically true if weak order (a <= b) && !(b <= a) <=>
* (a <= b) && (b > a) <=> (a < b) is satisfied:
*/
if(!OpT().apply(
right_traits().get(right,i),
left_traits().get(left,i)
))
return true;
/* Otherwise, have equality (a <= b) && (b <= a), so continue
* to next element:
*/
else
continue;
} else {
/* Total order isn't satisfied (a > b), so return false: */
return false;
}
}
/* XXX Can this be unrolled in any reasonable way? */
/* Total (==) or weak (<) order was satisfied, so return true: */
return true;
}
}
/* XXX There is a better way to handle these with operator traits... */
CML_QUAT_QUAT_ORDER( total_order, operator==, et::OpEqual)
CML_QUATXPR_QUAT_ORDER( total_order, operator==, et::OpEqual)
CML_QUAT_QUATXPR_ORDER( total_order, operator==, et::OpEqual)
CML_QUATXPR_QUATXPR_ORDER( total_order, operator==, et::OpEqual)
CML_QUAT_QUAT_ORDER( weak_order, operator!=, et::OpNotEqual)
CML_QUATXPR_QUAT_ORDER( weak_order, operator!=, et::OpNotEqual)
CML_QUAT_QUATXPR_ORDER( weak_order, operator!=, et::OpNotEqual)
CML_QUATXPR_QUATXPR_ORDER( weak_order, operator!=, et::OpNotEqual)
CML_QUAT_QUAT_ORDER( weak_order, operator<, et::OpLess)
CML_QUATXPR_QUAT_ORDER( weak_order, operator<, et::OpLess)
CML_QUAT_QUATXPR_ORDER( weak_order, operator<, et::OpLess)
CML_QUATXPR_QUATXPR_ORDER( weak_order, operator<, et::OpLess)
} // namespace cml
#endif
// -------------------------------------------------------------------------
// vim:ft=cpp