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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_REF_H
#define EIGEN_REF_H
// IWYU pragma: private
#include "./InternalHeaderCheck.h"
namespace Eigen {
namespace internal {
template<typename PlainObjectType_, int Options_, typename StrideType_>
struct traits<Ref<PlainObjectType_, Options_, StrideType_> >
: public traits<Map<PlainObjectType_, Options_, StrideType_> >
{
typedef PlainObjectType_ PlainObjectType;
typedef StrideType_ StrideType;
enum {
Options = Options_,
Flags = traits<Map<PlainObjectType_, Options_, StrideType_> >::Flags | NestByRefBit,
Alignment = traits<Map<PlainObjectType_, Options_, StrideType_> >::Alignment
};
template<typename Derived> struct match {
enum {
IsVectorAtCompileTime = PlainObjectType::IsVectorAtCompileTime || Derived::IsVectorAtCompileTime,
HasDirectAccess = internal::has_direct_access<Derived>::ret,
StorageOrderMatch = IsVectorAtCompileTime || ((PlainObjectType::Flags&RowMajorBit)==(Derived::Flags&RowMajorBit)),
InnerStrideMatch = int(StrideType::InnerStrideAtCompileTime)==int(Dynamic)
|| int(StrideType::InnerStrideAtCompileTime)==int(Derived::InnerStrideAtCompileTime)
|| (int(StrideType::InnerStrideAtCompileTime)==0 && int(Derived::InnerStrideAtCompileTime)==1),
OuterStrideMatch = IsVectorAtCompileTime
|| int(StrideType::OuterStrideAtCompileTime)==int(Dynamic) || int(StrideType::OuterStrideAtCompileTime)==int(Derived::OuterStrideAtCompileTime),
// NOTE, this indirection of evaluator<Derived>::Alignment is needed
// to workaround a very strange bug in MSVC related to the instantiation
// of has_*ary_operator in evaluator<CwiseNullaryOp>.
// This line is surprisingly very sensitive. For instance, simply adding parenthesis
// as "DerivedAlignment = (int(evaluator<Derived>::Alignment))," will make MSVC fail...
DerivedAlignment = int(evaluator<Derived>::Alignment),
AlignmentMatch = (int(traits<PlainObjectType>::Alignment)==int(Unaligned)) || (DerivedAlignment >= int(Alignment)), // FIXME the first condition is not very clear, it should be replaced by the required alignment
ScalarTypeMatch = internal::is_same<typename PlainObjectType::Scalar, typename Derived::Scalar>::value,
MatchAtCompileTime = HasDirectAccess && StorageOrderMatch && InnerStrideMatch && OuterStrideMatch && AlignmentMatch && ScalarTypeMatch
};
typedef std::conditional_t<MatchAtCompileTime,internal::true_type,internal::false_type> type;
};
};
template<typename Derived>
struct traits<RefBase<Derived> > : public traits<Derived> {};
}
template<typename Derived> class RefBase
: public MapBase<Derived>
{
typedef typename internal::traits<Derived>::PlainObjectType PlainObjectType;
typedef typename internal::traits<Derived>::StrideType StrideType;
public:
typedef MapBase<Derived> Base;
EIGEN_DENSE_PUBLIC_INTERFACE(RefBase)
EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index innerStride() const
{
return StrideType::InnerStrideAtCompileTime != 0 ? m_stride.inner() : 1;
}
EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR inline Index outerStride() const
{
return StrideType::OuterStrideAtCompileTime != 0 ? m_stride.outer()
: IsVectorAtCompileTime ? this->size()
: int(Flags)&RowMajorBit ? this->cols()
: this->rows();
}
EIGEN_DEVICE_FUNC RefBase()
: Base(0,RowsAtCompileTime==Dynamic?0:RowsAtCompileTime,ColsAtCompileTime==Dynamic?0:ColsAtCompileTime),
// Stride<> does not allow default ctor for Dynamic strides, so let' initialize it with dummy values:
m_stride(StrideType::OuterStrideAtCompileTime==Dynamic?0:StrideType::OuterStrideAtCompileTime,
StrideType::InnerStrideAtCompileTime==Dynamic?0:StrideType::InnerStrideAtCompileTime)
{}
EIGEN_INHERIT_ASSIGNMENT_OPERATORS(RefBase)
protected:
typedef Stride<StrideType::OuterStrideAtCompileTime,StrideType::InnerStrideAtCompileTime> StrideBase;
// Resolves inner stride if default 0.
static EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR Index resolveInnerStride(Index inner) {
return inner == 0 ? 1 : inner;
}
// Resolves outer stride if default 0.
static EIGEN_DEVICE_FUNC EIGEN_CONSTEXPR Index resolveOuterStride(Index inner, Index outer, Index rows, Index cols, bool isVectorAtCompileTime, bool isRowMajor) {
return outer == 0 ? isVectorAtCompileTime ? inner * rows * cols : isRowMajor ? inner * cols : inner * rows : outer;
}
// Returns true if construction is valid, false if there is a stride mismatch,
// and fails if there is a size mismatch.
template<typename Expression>
EIGEN_DEVICE_FUNC bool construct(Expression& expr)
{
// Check matrix sizes. If this is a compile-time vector, we do allow
// implicitly transposing.
EIGEN_STATIC_ASSERT(
EIGEN_PREDICATE_SAME_MATRIX_SIZE(PlainObjectType, Expression)
// If it is a vector, the transpose sizes might match.
|| ( PlainObjectType::IsVectorAtCompileTime
&& ((int(PlainObjectType::RowsAtCompileTime)==Eigen::Dynamic
|| int(Expression::ColsAtCompileTime)==Eigen::Dynamic
|| int(PlainObjectType::RowsAtCompileTime)==int(Expression::ColsAtCompileTime))
&& (int(PlainObjectType::ColsAtCompileTime)==Eigen::Dynamic
|| int(Expression::RowsAtCompileTime)==Eigen::Dynamic
|| int(PlainObjectType::ColsAtCompileTime)==int(Expression::RowsAtCompileTime)))),
YOU_MIXED_MATRICES_OF_DIFFERENT_SIZES
)
// Determine runtime rows and columns.
Index rows = expr.rows();
Index cols = expr.cols();
if(PlainObjectType::RowsAtCompileTime==1)
{
eigen_assert(expr.rows()==1 || expr.cols()==1);
rows = 1;
cols = expr.size();
}
else if(PlainObjectType::ColsAtCompileTime==1)
{
eigen_assert(expr.rows()==1 || expr.cols()==1);
rows = expr.size();
cols = 1;
}
// Verify that the sizes are valid.
eigen_assert(
(PlainObjectType::RowsAtCompileTime == Dynamic) || (PlainObjectType::RowsAtCompileTime == rows));
eigen_assert(
(PlainObjectType::ColsAtCompileTime == Dynamic) || (PlainObjectType::ColsAtCompileTime == cols));
// If this is a vector, we might be transposing, which means that stride should swap.
const bool transpose = PlainObjectType::IsVectorAtCompileTime && (rows != expr.rows());
// If the storage format differs, we also need to swap the stride.
const bool row_major = ((PlainObjectType::Flags)&RowMajorBit) != 0;
const bool expr_row_major = (Expression::Flags&RowMajorBit) != 0;
const bool storage_differs = (row_major != expr_row_major);
const bool swap_stride = (transpose != storage_differs);
// Determine expr's actual strides, resolving any defaults if zero.
const Index expr_inner_actual = resolveInnerStride(expr.innerStride());
const Index expr_outer_actual = resolveOuterStride(expr_inner_actual,
expr.outerStride(),
expr.rows(),
expr.cols(),
Expression::IsVectorAtCompileTime != 0,
expr_row_major);
// If this is a column-major row vector or row-major column vector, the inner-stride
// is arbitrary, so set it to either the compile-time inner stride or 1.
const bool row_vector = (rows == 1);
const bool col_vector = (cols == 1);
const Index inner_stride =
( (!row_major && row_vector) || (row_major && col_vector) ) ?
( StrideType::InnerStrideAtCompileTime > 0 ? Index(StrideType::InnerStrideAtCompileTime) : 1)
: swap_stride ? expr_outer_actual : expr_inner_actual;
// If this is a column-major column vector or row-major row vector, the outer-stride
// is arbitrary, so set it to either the compile-time outer stride or vector size.
const Index outer_stride =
( (!row_major && col_vector) || (row_major && row_vector) ) ?
( StrideType::OuterStrideAtCompileTime > 0 ? Index(StrideType::OuterStrideAtCompileTime) : rows * cols * inner_stride)
: swap_stride ? expr_inner_actual : expr_outer_actual;
// Check if given inner/outer strides are compatible with compile-time strides.
const bool inner_valid = (StrideType::InnerStrideAtCompileTime == Dynamic)
|| (resolveInnerStride(Index(StrideType::InnerStrideAtCompileTime)) == inner_stride);
if (!inner_valid) {
return false;
}
const bool outer_valid = (StrideType::OuterStrideAtCompileTime == Dynamic)
|| (resolveOuterStride(
inner_stride,
Index(StrideType::OuterStrideAtCompileTime),
rows, cols, PlainObjectType::IsVectorAtCompileTime != 0,
row_major)
== outer_stride);
if (!outer_valid) {
return false;
}
internal::construct_at<Base>(this, expr.data(), rows, cols);
internal::construct_at(&m_stride,
(StrideType::OuterStrideAtCompileTime == 0) ? 0 : outer_stride,
(StrideType::InnerStrideAtCompileTime == 0) ? 0 : inner_stride );
return true;
}
StrideBase m_stride;
};
/** \class Ref
* \ingroup Core_Module
*
* \brief A matrix or vector expression mapping an existing expression
*
* \tparam PlainObjectType the equivalent matrix type of the mapped data
* \tparam Options specifies the pointer alignment in bytes. It can be: \c #Aligned128, , \c #Aligned64, \c #Aligned32, \c #Aligned16, \c #Aligned8 or \c #Unaligned.
* The default is \c #Unaligned.
* \tparam StrideType optionally specifies strides. By default, Ref implies a contiguous storage along the inner dimension (inner stride==1),
* but accepts a variable outer stride (leading dimension).
* This can be overridden by specifying strides.
* The type passed here must be a specialization of the Stride template, see examples below.
*
* This class provides a way to write non-template functions taking Eigen objects as parameters while limiting the number of copies.
* A Ref<> object can represent either a const expression or a l-value:
* \code
* // in-out argument:
* void foo1(Ref<VectorXf> x);
*
* // read-only const argument:
* void foo2(const Ref<const VectorXf>& x);
* \endcode
*
* In the in-out case, the input argument must satisfy the constraints of the actual Ref<> type, otherwise a compilation issue will be triggered.
* By default, a Ref<VectorXf> can reference any dense vector expression of float having a contiguous memory layout.
* Likewise, a Ref<MatrixXf> can reference any column-major dense matrix expression of float whose column's elements are contiguously stored with
* the possibility to have a constant space in-between each column, i.e. the inner stride must be equal to 1, but the outer stride (or leading dimension)
* can be greater than the number of rows.
*
* In the const case, if the input expression does not match the above requirement, then it is evaluated into a temporary before being passed to the function.
* Here are some examples:
* \code
* MatrixXf A;
* VectorXf a;
* foo1(a.head()); // OK
* foo1(A.col()); // OK
* foo1(A.row()); // Compilation error because here innerstride!=1
* foo2(A.row()); // Compilation error because A.row() is a 1xN object while foo2 is expecting a Nx1 object
* foo2(A.row().transpose()); // The row is copied into a contiguous temporary
* foo2(2*a); // The expression is evaluated into a temporary
* foo2(A.col().segment(2,4)); // No temporary
* \endcode
*
* The range of inputs that can be referenced without temporary can be enlarged using the last two template parameters.
* Here is an example accepting an innerstride!=1:
* \code
* // in-out argument:
* void foo3(Ref<VectorXf,0,InnerStride<> > x);
* foo3(A.row()); // OK
* \endcode
* The downside here is that the function foo3 might be significantly slower than foo1 because it won't be able to exploit vectorization, and will involve more
* expensive address computations even if the input is contiguously stored in memory. To overcome this issue, one might propose to overload internally calling a
* template function, e.g.:
* \code
* // in the .h:
* void foo(const Ref<MatrixXf>& A);
* void foo(const Ref<MatrixXf,0,Stride<> >& A);
*
* // in the .cpp:
* template<typename TypeOfA> void foo_impl(const TypeOfA& A) {
* ... // crazy code goes here
* }
* void foo(const Ref<MatrixXf>& A) { foo_impl(A); }
* void foo(const Ref<MatrixXf,0,Stride<> >& A) { foo_impl(A); }
* \endcode
*
* See also the following stackoverflow questions for further references:
* - <a href="http://stackoverflow.com/questions/21132538/correct-usage-of-the-eigenref-class">Correct usage of the Eigen::Ref<> class</a>
*
* \sa PlainObjectBase::Map(), \ref TopicStorageOrders
*/
template<typename PlainObjectType, int Options, typename StrideType> class Ref
: public RefBase<Ref<PlainObjectType, Options, StrideType> >
{
private:
typedef internal::traits<Ref> Traits;
template<typename Derived>
EIGEN_DEVICE_FUNC inline Ref(const PlainObjectBase<Derived>& expr,
std::enable_if_t<bool(Traits::template match<Derived>::MatchAtCompileTime),Derived>* = 0);
public:
typedef RefBase<Ref> Base;
EIGEN_DENSE_PUBLIC_INTERFACE(Ref)
#ifndef EIGEN_PARSED_BY_DOXYGEN
template<typename Derived>
EIGEN_DEVICE_FUNC inline Ref(PlainObjectBase<Derived>& expr,
std::enable_if_t<bool(Traits::template match<Derived>::MatchAtCompileTime),Derived>* = 0)
{
EIGEN_STATIC_ASSERT(bool(Traits::template match<Derived>::MatchAtCompileTime), STORAGE_LAYOUT_DOES_NOT_MATCH);
// Construction must pass since we will not create temporary storage in the non-const case.
const bool success = Base::construct(expr.derived());
EIGEN_UNUSED_VARIABLE(success)
eigen_assert(success);
}
template<typename Derived>
EIGEN_DEVICE_FUNC inline Ref(const DenseBase<Derived>& expr,
std::enable_if_t<bool(Traits::template match<Derived>::MatchAtCompileTime),Derived>* = 0)
#else
/** Implicit constructor from any dense expression */
template<typename Derived>
inline Ref(DenseBase<Derived>& expr)
#endif
{
EIGEN_STATIC_ASSERT(bool(internal::is_lvalue<Derived>::value), THIS_EXPRESSION_IS_NOT_A_LVALUE__IT_IS_READ_ONLY);
EIGEN_STATIC_ASSERT(bool(Traits::template match<Derived>::MatchAtCompileTime), STORAGE_LAYOUT_DOES_NOT_MATCH);
EIGEN_STATIC_ASSERT(!Derived::IsPlainObjectBase,THIS_EXPRESSION_IS_NOT_A_LVALUE__IT_IS_READ_ONLY);
// Construction must pass since we will not create temporary storage in the non-const case.
const bool success = Base::construct(expr.const_cast_derived());
EIGEN_UNUSED_VARIABLE(success)
eigen_assert(success);
}
EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Ref)
};
// this is the const ref version
template<typename TPlainObjectType, int Options, typename StrideType> class Ref<const TPlainObjectType, Options, StrideType>
: public RefBase<Ref<const TPlainObjectType, Options, StrideType> >
{
typedef internal::traits<Ref> Traits;
static constexpr bool may_map_m_object_successfully =
(static_cast<int>(StrideType::InnerStrideAtCompileTime) == 0 ||
static_cast<int>(StrideType::InnerStrideAtCompileTime) == 1 ||
static_cast<int>(StrideType::InnerStrideAtCompileTime) == Dynamic) &&
(TPlainObjectType::IsVectorAtCompileTime ||
static_cast<int>(StrideType::OuterStrideAtCompileTime) == 0 ||
static_cast<int>(StrideType::OuterStrideAtCompileTime) == Dynamic ||
static_cast<int>(StrideType::OuterStrideAtCompileTime) == static_cast<int>(TPlainObjectType::InnerSizeAtCompileTime) ||
static_cast<int>(TPlainObjectType::InnerSizeAtCompileTime) == Dynamic);
public:
typedef RefBase<Ref> Base;
EIGEN_DENSE_PUBLIC_INTERFACE(Ref)
template<typename Derived>
EIGEN_DEVICE_FUNC inline Ref(const DenseBase<Derived>& expr,
std::enable_if_t<bool(Traits::template match<Derived>::ScalarTypeMatch),Derived>* = 0)
{
// std::cout << match_helper<Derived>::HasDirectAccess << "," << match_helper<Derived>::OuterStrideMatch << "," << match_helper<Derived>::InnerStrideMatch << "\n";
// std::cout << int(StrideType::OuterStrideAtCompileTime) << " - " << int(Derived::OuterStrideAtCompileTime) << "\n";
// std::cout << int(StrideType::InnerStrideAtCompileTime) << " - " << int(Derived::InnerStrideAtCompileTime) << "\n";
EIGEN_STATIC_ASSERT(Traits::template match<Derived>::type::value || may_map_m_object_successfully,
STORAGE_LAYOUT_DOES_NOT_MATCH);
construct(expr.derived(), typename Traits::template match<Derived>::type());
}
EIGEN_DEVICE_FUNC inline Ref(const Ref& other) : Base(other) {
// copy constructor shall not copy the m_object, to avoid unnecessary malloc and copy
}
EIGEN_DEVICE_FUNC inline Ref(Ref&& other) {
if (other.data() == other.m_object.data()) {
m_object = std::move(other.m_object);
Base::construct(m_object);
}
else
Base::construct(other);
}
template<typename OtherRef>
EIGEN_DEVICE_FUNC inline Ref(const RefBase<OtherRef>& other) {
EIGEN_STATIC_ASSERT(Traits::template match<OtherRef>::type::value || may_map_m_object_successfully,
STORAGE_LAYOUT_DOES_NOT_MATCH);
construct(other.derived(), typename Traits::template match<OtherRef>::type());
}
protected:
template<typename Expression>
EIGEN_DEVICE_FUNC void construct(const Expression& expr,internal::true_type)
{
// Check if we can use the underlying expr's storage directly, otherwise call the copy version.
if (!Base::construct(expr)) {
construct(expr, internal::false_type());
}
}
template<typename Expression>
EIGEN_DEVICE_FUNC void construct(const Expression& expr, internal::false_type)
{
internal::call_assignment_no_alias(m_object,expr,internal::assign_op<Scalar,Scalar>());
const bool success = Base::construct(m_object);
EIGEN_ONLY_USED_FOR_DEBUG(success)
eigen_assert(success);
}
protected:
TPlainObjectType m_object;
};
} // end namespace Eigen
#endif // EIGEN_REF_H