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      1 // This file is part of Eigen, a lightweight C++ template library
      2 // for linear algebra.
      3 //
      4 // Copyright (C) 2008-2015 Gael Guennebaud <gael.guennebaud (at) inria.fr>
      5 // Copyright (C) 2007-2009 Benoit Jacob <jacob.benoit.1 (at) gmail.com>
      6 //
      7 // This Source Code Form is subject to the terms of the Mozilla
      8 // Public License v. 2.0. If a copy of the MPL was not distributed
      9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
     10 
     11 #ifndef EIGEN_CONSTANTS_H
     12 #define EIGEN_CONSTANTS_H
     13 
     14 namespace Eigen {
     15 
     16 /** This value means that a positive quantity (e.g., a size) is not known at compile-time, and that instead the value is
     17   * stored in some runtime variable.
     18   *
     19   * Changing the value of Dynamic breaks the ABI, as Dynamic is often used as a template parameter for Matrix.
     20   */
     21 const int Dynamic = -1;
     22 
     23 /** This value means that a signed quantity (e.g., a signed index) is not known at compile-time, and that instead its value
     24   * has to be specified at runtime.
     25   */
     26 const int DynamicIndex = 0xffffff;
     27 
     28 /** This value means +Infinity; it is currently used only as the p parameter to MatrixBase::lpNorm<int>().
     29   * The value Infinity there means the L-infinity norm.
     30   */
     31 const int Infinity = -1;
     32 
     33 /** This value means that the cost to evaluate an expression coefficient is either very expensive or
     34   * cannot be known at compile time.
     35   *
     36   * This value has to be positive to (1) simplify cost computation, and (2) allow to distinguish between a very expensive and very very expensive expressions.
     37   * It thus must also be large enough to make sure unrolling won't happen and that sub expressions will be evaluated, but not too large to avoid overflow.
     38   */
     39 const int HugeCost = 10000;
     40 
     41 /** \defgroup flags Flags
     42   * \ingroup Core_Module
     43   *
     44   * These are the possible bits which can be OR'ed to constitute the flags of a matrix or
     45   * expression.
     46   *
     47   * It is important to note that these flags are a purely compile-time notion. They are a compile-time property of
     48   * an expression type, implemented as enum's. They are not stored in memory at runtime, and they do not incur any
     49   * runtime overhead.
     50   *
     51   * \sa MatrixBase::Flags
     52   */
     53 
     54 /** \ingroup flags
     55   *
     56   * for a matrix, this means that the storage order is row-major.
     57   * If this bit is not set, the storage order is column-major.
     58   * For an expression, this determines the storage order of
     59   * the matrix created by evaluation of that expression.
     60   * \sa \blank  \ref TopicStorageOrders */
     61 const unsigned int RowMajorBit = 0x1;
     62 
     63 /** \ingroup flags
     64   * means the expression should be evaluated by the calling expression */
     65 const unsigned int EvalBeforeNestingBit = 0x2;
     66 
     67 /** \ingroup flags
     68   * \deprecated
     69   * means the expression should be evaluated before any assignment */
     70 EIGEN_DEPRECATED
     71 const unsigned int EvalBeforeAssigningBit = 0x4; // FIXME deprecated
     72 
     73 /** \ingroup flags
     74   *
     75   * Short version: means the expression might be vectorized
     76   *
     77   * Long version: means that the coefficients can be handled by packets
     78   * and start at a memory location whose alignment meets the requirements
     79   * of the present CPU architecture for optimized packet access. In the fixed-size
     80   * case, there is the additional condition that it be possible to access all the
     81   * coefficients by packets (this implies the requirement that the size be a multiple of 16 bytes,
     82   * and that any nontrivial strides don't break the alignment). In the dynamic-size case,
     83   * there is no such condition on the total size and strides, so it might not be possible to access
     84   * all coeffs by packets.
     85   *
     86   * \note This bit can be set regardless of whether vectorization is actually enabled.
     87   *       To check for actual vectorizability, see \a ActualPacketAccessBit.
     88   */
     89 const unsigned int PacketAccessBit = 0x8;
     90 
     91 #ifdef EIGEN_VECTORIZE
     92 /** \ingroup flags
     93   *
     94   * If vectorization is enabled (EIGEN_VECTORIZE is defined) this constant
     95   * is set to the value \a PacketAccessBit.
     96   *
     97   * If vectorization is not enabled (EIGEN_VECTORIZE is not defined) this constant
     98   * is set to the value 0.
     99   */
    100 const unsigned int ActualPacketAccessBit = PacketAccessBit;
    101 #else
    102 const unsigned int ActualPacketAccessBit = 0x0;
    103 #endif
    104 
    105 /** \ingroup flags
    106   *
    107   * Short version: means the expression can be seen as 1D vector.
    108   *
    109   * Long version: means that one can access the coefficients
    110   * of this expression by coeff(int), and coeffRef(int) in the case of a lvalue expression. These
    111   * index-based access methods are guaranteed
    112   * to not have to do any runtime computation of a (row, col)-pair from the index, so that it
    113   * is guaranteed that whenever it is available, index-based access is at least as fast as
    114   * (row,col)-based access. Expressions for which that isn't possible don't have the LinearAccessBit.
    115   *
    116   * If both PacketAccessBit and LinearAccessBit are set, then the
    117   * packets of this expression can be accessed by packet(int), and writePacket(int) in the case of a
    118   * lvalue expression.
    119   *
    120   * Typically, all vector expressions have the LinearAccessBit, but there is one exception:
    121   * Product expressions don't have it, because it would be troublesome for vectorization, even when the
    122   * Product is a vector expression. Thus, vector Product expressions allow index-based coefficient access but
    123   * not index-based packet access, so they don't have the LinearAccessBit.
    124   */
    125 const unsigned int LinearAccessBit = 0x10;
    126 
    127 /** \ingroup flags
    128   *
    129   * Means the expression has a coeffRef() method, i.e. is writable as its individual coefficients are directly addressable.
    130   * This rules out read-only expressions.
    131   *
    132   * Note that DirectAccessBit and LvalueBit are mutually orthogonal, as there are examples of expression having one but note
    133   * the other:
    134   *   \li writable expressions that don't have a very simple memory layout as a strided array, have LvalueBit but not DirectAccessBit
    135   *   \li Map-to-const expressions, for example Map<const Matrix>, have DirectAccessBit but not LvalueBit
    136   *
    137   * Expressions having LvalueBit also have their coeff() method returning a const reference instead of returning a new value.
    138   */
    139 const unsigned int LvalueBit = 0x20;
    140 
    141 /** \ingroup flags
    142   *
    143   * Means that the underlying array of coefficients can be directly accessed as a plain strided array. The memory layout
    144   * of the array of coefficients must be exactly the natural one suggested by rows(), cols(),
    145   * outerStride(), innerStride(), and the RowMajorBit. This rules out expressions such as Diagonal, whose coefficients,
    146   * though referencable, do not have such a regular memory layout.
    147   *
    148   * See the comment on LvalueBit for an explanation of how LvalueBit and DirectAccessBit are mutually orthogonal.
    149   */
    150 const unsigned int DirectAccessBit = 0x40;
    151 
    152 /** \deprecated \ingroup flags
    153   *
    154   * means the first coefficient packet is guaranteed to be aligned.
    155   * An expression cannot has the AlignedBit without the PacketAccessBit flag.
    156   * In other words, this means we are allow to perform an aligned packet access to the first element regardless
    157   * of the expression kind:
    158   * \code
    159   * expression.packet<Aligned>(0);
    160   * \endcode
    161   */
    162 EIGEN_DEPRECATED const unsigned int AlignedBit = 0x80;
    163 
    164 const unsigned int NestByRefBit = 0x100;
    165 
    166 /** \ingroup flags
    167   *
    168   * for an expression, this means that the storage order
    169   * can be either row-major or column-major.
    170   * The precise choice will be decided at evaluation time or when
    171   * combined with other expressions.
    172   * \sa \blank  \ref RowMajorBit, \ref TopicStorageOrders */
    173 const unsigned int NoPreferredStorageOrderBit = 0x200;
    174 
    175 /** \ingroup flags
    176   *
    177   * Means that the underlying coefficients can be accessed through pointers to the sparse (un)compressed storage format,
    178   * that is, the expression provides:
    179   * \code
    180     inline const Scalar* valuePtr() const;
    181     inline const Index* innerIndexPtr() const;
    182     inline const Index* outerIndexPtr() const;
    183     inline const Index* innerNonZeroPtr() const;
    184     \endcode
    185   */
    186 const unsigned int CompressedAccessBit = 0x400;
    187 
    188 
    189 // list of flags that are inherited by default
    190 const unsigned int HereditaryBits = RowMajorBit
    191                                   | EvalBeforeNestingBit;
    192 
    193 /** \defgroup enums Enumerations
    194   * \ingroup Core_Module
    195   *
    196   * Various enumerations used in %Eigen. Many of these are used as template parameters.
    197   */
    198 
    199 /** \ingroup enums
    200   * Enum containing possible values for the \c Mode or \c UpLo parameter of
    201   * MatrixBase::selfadjointView() and MatrixBase::triangularView(), and selfadjoint solvers. */
    202 enum UpLoType {
    203   /** View matrix as a lower triangular matrix. */
    204   Lower=0x1,
    205   /** View matrix as an upper triangular matrix. */
    206   Upper=0x2,
    207   /** %Matrix has ones on the diagonal; to be used in combination with #Lower or #Upper. */
    208   UnitDiag=0x4,
    209   /** %Matrix has zeros on the diagonal; to be used in combination with #Lower or #Upper. */
    210   ZeroDiag=0x8,
    211   /** View matrix as a lower triangular matrix with ones on the diagonal. */
    212   UnitLower=UnitDiag|Lower,
    213   /** View matrix as an upper triangular matrix with ones on the diagonal. */
    214   UnitUpper=UnitDiag|Upper,
    215   /** View matrix as a lower triangular matrix with zeros on the diagonal. */
    216   StrictlyLower=ZeroDiag|Lower,
    217   /** View matrix as an upper triangular matrix with zeros on the diagonal. */
    218   StrictlyUpper=ZeroDiag|Upper,
    219   /** Used in BandMatrix and SelfAdjointView to indicate that the matrix is self-adjoint. */
    220   SelfAdjoint=0x10,
    221   /** Used to support symmetric, non-selfadjoint, complex matrices. */
    222   Symmetric=0x20
    223 };
    224 
    225 /** \ingroup enums
    226   * Enum for indicating whether a buffer is aligned or not. */
    227 enum AlignmentType {
    228   Unaligned=0,        /**< Data pointer has no specific alignment. */
    229   Aligned8=8,         /**< Data pointer is aligned on a 8 bytes boundary. */
    230   Aligned16=16,       /**< Data pointer is aligned on a 16 bytes boundary. */
    231   Aligned32=32,       /**< Data pointer is aligned on a 32 bytes boundary. */
    232   Aligned64=64,       /**< Data pointer is aligned on a 64 bytes boundary. */
    233   Aligned128=128,     /**< Data pointer is aligned on a 128 bytes boundary. */
    234   AlignedMask=255,
    235   Aligned=16,         /**< \deprecated Synonym for Aligned16. */
    236 #if EIGEN_MAX_ALIGN_BYTES==128
    237   AlignedMax = Aligned128
    238 #elif EIGEN_MAX_ALIGN_BYTES==64
    239   AlignedMax = Aligned64
    240 #elif EIGEN_MAX_ALIGN_BYTES==32
    241   AlignedMax = Aligned32
    242 #elif EIGEN_MAX_ALIGN_BYTES==16
    243   AlignedMax = Aligned16
    244 #elif EIGEN_MAX_ALIGN_BYTES==8
    245   AlignedMax = Aligned8
    246 #elif EIGEN_MAX_ALIGN_BYTES==0
    247   AlignedMax = Unaligned
    248 #else
    249 #error Invalid value for EIGEN_MAX_ALIGN_BYTES
    250 #endif
    251 };
    252 
    253 /** \ingroup enums
    254  * Enum used by DenseBase::corner() in Eigen2 compatibility mode. */
    255 // FIXME after the corner() API change, this was not needed anymore, except by AlignedBox
    256 // TODO: find out what to do with that. Adapt the AlignedBox API ?
    257 enum CornerType { TopLeft, TopRight, BottomLeft, BottomRight };
    258 
    259 /** \ingroup enums
    260   * Enum containing possible values for the \p Direction parameter of
    261   * Reverse, PartialReduxExpr and VectorwiseOp. */
    262 enum DirectionType {
    263   /** For Reverse, all columns are reversed;
    264     * for PartialReduxExpr and VectorwiseOp, act on columns. */
    265   Vertical,
    266   /** For Reverse, all rows are reversed;
    267     * for PartialReduxExpr and VectorwiseOp, act on rows. */
    268   Horizontal,
    269   /** For Reverse, both rows and columns are reversed;
    270     * not used for PartialReduxExpr and VectorwiseOp. */
    271   BothDirections
    272 };
    273 
    274 /** \internal \ingroup enums
    275   * Enum to specify how to traverse the entries of a matrix. */
    276 enum TraversalType {
    277   /** \internal Default traversal, no vectorization, no index-based access */
    278   DefaultTraversal,
    279   /** \internal No vectorization, use index-based access to have only one for loop instead of 2 nested loops */
    280   LinearTraversal,
    281   /** \internal Equivalent to a slice vectorization for fixed-size matrices having good alignment
    282     * and good size */
    283   InnerVectorizedTraversal,
    284   /** \internal Vectorization path using a single loop plus scalar loops for the
    285     * unaligned boundaries */
    286   LinearVectorizedTraversal,
    287   /** \internal Generic vectorization path using one vectorized loop per row/column with some
    288     * scalar loops to handle the unaligned boundaries */
    289   SliceVectorizedTraversal,
    290   /** \internal Special case to properly handle incompatible scalar types or other defecting cases*/
    291   InvalidTraversal,
    292   /** \internal Evaluate all entries at once */
    293   AllAtOnceTraversal
    294 };
    295 
    296 /** \internal \ingroup enums
    297   * Enum to specify whether to unroll loops when traversing over the entries of a matrix. */
    298 enum UnrollingType {
    299   /** \internal Do not unroll loops. */
    300   NoUnrolling,
    301   /** \internal Unroll only the inner loop, but not the outer loop. */
    302   InnerUnrolling,
    303   /** \internal Unroll both the inner and the outer loop. If there is only one loop,
    304     * because linear traversal is used, then unroll that loop. */
    305   CompleteUnrolling
    306 };
    307 
    308 /** \internal \ingroup enums
    309   * Enum to specify whether to use the default (built-in) implementation or the specialization. */
    310 enum SpecializedType {
    311   Specialized,
    312   BuiltIn
    313 };
    314 
    315 /** \ingroup enums
    316   * Enum containing possible values for the \p _Options template parameter of
    317   * Matrix, Array and BandMatrix. */
    318 enum StorageOptions {
    319   /** Storage order is column major (see \ref TopicStorageOrders). */
    320   ColMajor = 0,
    321   /** Storage order is row major (see \ref TopicStorageOrders). */
    322   RowMajor = 0x1,  // it is only a coincidence that this is equal to RowMajorBit -- don't rely on that
    323   /** Align the matrix itself if it is vectorizable fixed-size */
    324   AutoAlign = 0,
    325   /** Don't require alignment for the matrix itself (the array of coefficients, if dynamically allocated, may still be requested to be aligned) */ // FIXME --- clarify the situation
    326   DontAlign = 0x2
    327 };
    328 
    329 /** \ingroup enums
    330   * Enum for specifying whether to apply or solve on the left or right. */
    331 enum SideType {
    332   /** Apply transformation on the left. */
    333   OnTheLeft = 1,
    334   /** Apply transformation on the right. */
    335   OnTheRight = 2
    336 };
    337 
    338 /* the following used to be written as:
    339  *
    340  *   struct NoChange_t {};
    341  *   namespace {
    342  *     EIGEN_UNUSED NoChange_t NoChange;
    343  *   }
    344  *
    345  * on the ground that it feels dangerous to disambiguate overloaded functions on enum/integer types.
    346  * However, this leads to "variable declared but never referenced" warnings on Intel Composer XE,
    347  * and we do not know how to get rid of them (bug 450).
    348  */
    349 
    350 enum NoChange_t   { NoChange };
    351 enum Sequential_t { Sequential };
    352 enum Default_t    { Default };
    353 
    354 /** \internal \ingroup enums
    355   * Used in AmbiVector. */
    356 enum AmbiVectorMode {
    357   IsDense         = 0,
    358   IsSparse
    359 };
    360 
    361 /** \ingroup enums
    362   * Used as template parameter in DenseCoeffBase and MapBase to indicate
    363   * which accessors should be provided. */
    364 enum AccessorLevels {
    365   /** Read-only access via a member function. */
    366   ReadOnlyAccessors,
    367   /** Read/write access via member functions. */
    368   WriteAccessors,
    369   /** Direct read-only access to the coefficients. */
    370   DirectAccessors,
    371   /** Direct read/write access to the coefficients. */
    372   DirectWriteAccessors
    373 };
    374 
    375 /** \ingroup enums
    376   * Enum with options to give to various decompositions. */
    377 enum DecompositionOptions {
    378   /** \internal Not used (meant for LDLT?). */
    379   Pivoting            = 0x01,
    380   /** \internal Not used (meant for LDLT?). */
    381   NoPivoting          = 0x02,
    382   /** Used in JacobiSVD to indicate that the square matrix U is to be computed. */
    383   ComputeFullU        = 0x04,
    384   /** Used in JacobiSVD to indicate that the thin matrix U is to be computed. */
    385   ComputeThinU        = 0x08,
    386   /** Used in JacobiSVD to indicate that the square matrix V is to be computed. */
    387   ComputeFullV        = 0x10,
    388   /** Used in JacobiSVD to indicate that the thin matrix V is to be computed. */
    389   ComputeThinV        = 0x20,
    390   /** Used in SelfAdjointEigenSolver and GeneralizedSelfAdjointEigenSolver to specify
    391     * that only the eigenvalues are to be computed and not the eigenvectors. */
    392   EigenvaluesOnly     = 0x40,
    393   /** Used in SelfAdjointEigenSolver and GeneralizedSelfAdjointEigenSolver to specify
    394     * that both the eigenvalues and the eigenvectors are to be computed. */
    395   ComputeEigenvectors = 0x80,
    396   /** \internal */
    397   EigVecMask = EigenvaluesOnly | ComputeEigenvectors,
    398   /** Used in GeneralizedSelfAdjointEigenSolver to indicate that it should
    399     * solve the generalized eigenproblem \f$ Ax = \lambda B x \f$. */
    400   Ax_lBx              = 0x100,
    401   /** Used in GeneralizedSelfAdjointEigenSolver to indicate that it should
    402     * solve the generalized eigenproblem \f$ ABx = \lambda x \f$. */
    403   ABx_lx              = 0x200,
    404   /** Used in GeneralizedSelfAdjointEigenSolver to indicate that it should
    405     * solve the generalized eigenproblem \f$ BAx = \lambda x \f$. */
    406   BAx_lx              = 0x400,
    407   /** \internal */
    408   GenEigMask = Ax_lBx | ABx_lx | BAx_lx
    409 };
    410 
    411 /** \ingroup enums
    412   * Possible values for the \p QRPreconditioner template parameter of JacobiSVD. */
    413 enum QRPreconditioners {
    414   /** Do not specify what is to be done if the SVD of a non-square matrix is asked for. */
    415   NoQRPreconditioner,
    416   /** Use a QR decomposition without pivoting as the first step. */
    417   HouseholderQRPreconditioner,
    418   /** Use a QR decomposition with column pivoting as the first step. */
    419   ColPivHouseholderQRPreconditioner,
    420   /** Use a QR decomposition with full pivoting as the first step. */
    421   FullPivHouseholderQRPreconditioner
    422 };
    423 
    424 #ifdef Success
    425 #error The preprocessor symbol 'Success' is defined, possibly by the X11 header file X.h
    426 #endif
    427 
    428 /** \ingroup enums
    429   * Enum for reporting the status of a computation. */
    430 enum ComputationInfo {
    431   /** Computation was successful. */
    432   Success = 0,
    433   /** The provided data did not satisfy the prerequisites. */
    434   NumericalIssue = 1,
    435   /** Iterative procedure did not converge. */
    436   NoConvergence = 2,
    437   /** The inputs are invalid, or the algorithm has been improperly called.
    438     * When assertions are enabled, such errors trigger an assert. */
    439   InvalidInput = 3
    440 };
    441 
    442 /** \ingroup enums
    443   * Enum used to specify how a particular transformation is stored in a matrix.
    444   * \sa Transform, Hyperplane::transform(). */
    445 enum TransformTraits {
    446   /** Transformation is an isometry. */
    447   Isometry      = 0x1,
    448   /** Transformation is an affine transformation stored as a (Dim+1)^2 matrix whose last row is
    449     * assumed to be [0 ... 0 1]. */
    450   Affine        = 0x2,
    451   /** Transformation is an affine transformation stored as a (Dim) x (Dim+1) matrix. */
    452   AffineCompact = 0x10 | Affine,
    453   /** Transformation is a general projective transformation stored as a (Dim+1)^2 matrix. */
    454   Projective    = 0x20
    455 };
    456 
    457 /** \internal \ingroup enums
    458   * Enum used to choose between implementation depending on the computer architecture. */
    459 namespace Architecture
    460 {
    461   enum Type {
    462     Generic = 0x0,
    463     SSE = 0x1,
    464     AltiVec = 0x2,
    465     VSX = 0x3,
    466     NEON = 0x4,
    467 #if defined EIGEN_VECTORIZE_SSE
    468     Target = SSE
    469 #elif defined EIGEN_VECTORIZE_ALTIVEC
    470     Target = AltiVec
    471 #elif defined EIGEN_VECTORIZE_VSX
    472     Target = VSX
    473 #elif defined EIGEN_VECTORIZE_NEON
    474     Target = NEON
    475 #else
    476     Target = Generic
    477 #endif
    478   };
    479 }
    480 
    481 /** \internal \ingroup enums
    482   * Enum used as template parameter in Product and product evaluators. */
    483 enum ProductImplType
    484 { DefaultProduct=0, LazyProduct, AliasFreeProduct, CoeffBasedProductMode, LazyCoeffBasedProductMode, OuterProduct, InnerProduct, GemvProduct, GemmProduct };
    485 
    486 /** \internal \ingroup enums
    487   * Enum used in experimental parallel implementation. */
    488 enum Action {GetAction, SetAction};
    489 
    490 /** The type used to identify a dense storage. */
    491 struct Dense {};
    492 
    493 /** The type used to identify a general sparse storage. */
    494 struct Sparse {};
    495 
    496 /** The type used to identify a general solver (factored) storage. */
    497 struct SolverStorage {};
    498 
    499 /** The type used to identify a permutation storage. */
    500 struct PermutationStorage {};
    501 
    502 /** The type used to identify a permutation storage. */
    503 struct TranspositionsStorage {};
    504 
    505 /** The type used to identify a matrix expression */
    506 struct MatrixXpr {};
    507 
    508 /** The type used to identify an array expression */
    509 struct ArrayXpr {};
    510 
    511 // An evaluator must define its shape. By default, it can be one of the following:
    512 struct DenseShape             { static std::string debugName() { return "DenseShape"; } };
    513 struct SolverShape            { static std::string debugName() { return "SolverShape"; } };
    514 struct HomogeneousShape       { static std::string debugName() { return "HomogeneousShape"; } };
    515 struct DiagonalShape          { static std::string debugName() { return "DiagonalShape"; } };
    516 struct BandShape              { static std::string debugName() { return "BandShape"; } };
    517 struct TriangularShape        { static std::string debugName() { return "TriangularShape"; } };
    518 struct SelfAdjointShape       { static std::string debugName() { return "SelfAdjointShape"; } };
    519 struct PermutationShape       { static std::string debugName() { return "PermutationShape"; } };
    520 struct TranspositionsShape    { static std::string debugName() { return "TranspositionsShape"; } };
    521 struct SparseShape            { static std::string debugName() { return "SparseShape"; } };
    522 
    523 namespace internal {
    524 
    525   // random access iterators based on coeff*() accessors.
    526 struct IndexBased {};
    527 
    528 // evaluator based on iterators to access coefficients.
    529 struct IteratorBased {};
    530 
    531 /** \internal
    532  * Constants for comparison functors
    533  */
    534 enum ComparisonName {
    535   cmp_EQ = 0,
    536   cmp_LT = 1,
    537   cmp_LE = 2,
    538   cmp_UNORD = 3,
    539   cmp_NEQ = 4,
    540   cmp_GT = 5,
    541   cmp_GE = 6
    542 };
    543 } // end namespace internal
    544 
    545 } // end namespace Eigen
    546 
    547 #endif // EIGEN_CONSTANTS_H
    548