Quelle Ref.h Sprache: C

// 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

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 typename internal::conditional<MatchAtCompileTime,internal::true_type,internal::false_type>::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;
    }

    ::new (static_cast<Base*>(this)) Base(expr.data(), rows, cols);
    ::new (&m_stride) StrideBase(
      (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,
                                 typename internal::enable_if<bool(Traits::template match<Derived>::MatchAtCompileTime),Derived>::type* = 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,
                                 typename internal::enable_if<bool(Traits::template match<Derived>::MatchAtCompileTime),Derived>::type* = 0)
    {
      EIGEN_STATIC_ASSERT(bool(Traits::template match<Derived>::MatchAtCompileTime), STORAGE_LAYOUT_DOES_NOT_MATCH);
      // Construction must pass since we will not create temprary 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,
                                 typename internal::enable_if<bool(Traits::template match<Derived>::MatchAtCompileTime),Derived>::type* = 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;
  public:

    typedef RefBase<Ref> Base;
    EIGEN_DENSE_PUBLIC_INTERFACE(Ref)

    template<typename Derived>
    EIGEN_DEVICE_FUNC inline Ref(const DenseBase<Derived>& expr,
                                 typename internal::enable_if<bool(Traits::template match<Derived>::ScalarTypeMatch),Derived>::type* = 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";
      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
    }

    template<typename OtherRef>
    EIGEN_DEVICE_FUNC inline Ref(const RefBase<OtherRef>& other) {
      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>());
      Base::construct(m_object);
    }

  protected:
    TPlainObjectType m_object;
};

} // end namespace Eigen

#endif // EIGEN_REF_H

quality96%

¤ Dauer der Verarbeitung: 0.16 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.