update eigen

1 files changed, 139 insertions, 437 deletions

diff --git a/eigen/Eigen/src/plugins/BlockMethods.h b/eigen/Eigen/src/plugins/BlockMethods.h
index 5caf144..ac35a00 100644
--- a/eigen/Eigen/src/plugins/BlockMethods.h
+++ b/eigen/Eigen/src/plugins/BlockMethods.h
@@ -42,116 +42,66 @@ template<int Size> struct ConstFixedSegmentReturnType { typedef const VectorBloc
 
 #endif // not EIGEN_PARSED_BY_DOXYGEN
 
-/// \returns an expression of a block in \c *this with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of a block in *this.
 ///
-/// \param  startRow  the first row in the block
-/// \param  startCol  the first column in the block
-/// \param  blockRows number of rows in the block, specified at either run-time or compile-time
-/// \param  blockCols number of columns in the block, specified at either run-time or compile-time
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
+/// \param startRow the first row in the block
+/// \param startCol the first column in the block
+/// \param blockRows the number of rows in the block
+/// \param blockCols the number of columns in the block
 ///
-/// Example using runtime (aka dynamic) sizes: \include MatrixBase_block_int_int_int_int.cpp
+/// Example: \include MatrixBase_block_int_int_int_int.cpp
 /// Output: \verbinclude MatrixBase_block_int_int_int_int.out
 ///
-/// \newin{3.4}:
-///
-/// The number of rows \a blockRows and columns \a blockCols can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments. In the later case, \c n plays the role of a runtime fallback value in case \c N equals Eigen::Dynamic.
-/// Here is an example with a fixed number of rows \c NRows and dynamic number of columns \c cols:
-/// \code
-/// mat.block(i,j,fix<NRows>,cols)
-/// \endcode
-///
-/// This function thus fully covers the features offered by the following overloads block<NRows,NCols>(Index, Index),
-/// and block<NRows,NCols>(Index, Index, Index, Index) that are thus obsolete. Indeed, this generic version avoids
-/// redundancy, it preserves the argument order, and prevents the need to rely on the template keyword in templated code.
-///
-/// but with less redundancy and more consistency as it does not modify the argument order
-/// and seamlessly enable hybrid fixed/dynamic sizes.
-///
-/// \note Even in the case that the returned expression has dynamic size, in the case
+/// \note Even though the returned expression has dynamic size, in the case
 /// when it is applied to a fixed-size matrix, it inherits a fixed maximal size,
 /// which means that evaluating it does not cause a dynamic memory allocation.
 ///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa class Block, fix, fix<N>(int)
+/// \sa class Block, block(Index,Index)
 ///
-template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename FixedBlockXpr<...,...>::Type
-#endif
-block(Index startRow, Index startCol, NRowsType blockRows, NColsType blockCols)
+inline BlockXpr block(Index startRow, Index startCol, Index blockRows, Index blockCols)
 {
-  return typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type(
-            derived(), startRow, startCol, internal::get_runtime_value(blockRows), internal::get_runtime_value(blockCols));
+  return BlockXpr(derived(), startRow, startCol, blockRows, blockCols);
 }
 
-/// This is the const version of block(Index,Index,NRowsType,NColsType)
-template<typename NRowsType, typename NColsType>
+/// This is the const version of block(Index,Index,Index,Index). */
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstFixedBlockXpr<...,...>::Type
-#endif
-block(Index startRow, Index startCol, NRowsType blockRows, NColsType blockCols) const
+inline const ConstBlockXpr block(Index startRow, Index startCol, Index blockRows, Index blockCols) const
 {
-  return typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type(
-            derived(), startRow, startCol, internal::get_runtime_value(blockRows), internal::get_runtime_value(blockCols));
+  return ConstBlockXpr(derived(), startRow, startCol, blockRows, blockCols);
 }
 
 
 
-/// \returns a expression of a top-right corner of \c *this with either dynamic or fixed sizes.
+
+/// \returns a dynamic-size expression of a top-right corner of *this.
 ///
 /// \param cRows the number of rows in the corner
 /// \param cCols the number of columns in the corner
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
-/// Example with dynamic sizes: \include MatrixBase_topRightCorner_int_int.cpp
+/// Example: \include MatrixBase_topRightCorner_int_int.cpp
 /// Output: \verbinclude MatrixBase_topRightCorner_int_int.out
 ///
-/// The number of rows \a blockRows and columns \a blockCols can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments. See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename FixedBlockXpr<...,...>::Type
-#endif
-topRightCorner(NRowsType cRows, NColsType cCols)
+inline BlockXpr topRightCorner(Index cRows, Index cCols)
 {
-  return typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, cols() - internal::get_runtime_value(cCols), internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return BlockXpr(derived(), 0, cols() - cCols, cRows, cCols);
 }
 
-/// This is the const version of topRightCorner(NRowsType, NColsType).
-template<typename NRowsType, typename NColsType>
+/// This is the const version of topRightCorner(Index, Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstFixedBlockXpr<...,...>::Type
-#endif
-topRightCorner(NRowsType cRows, NColsType cCols) const
+inline const ConstBlockXpr topRightCorner(Index cRows, Index cCols) const
 {
-  return typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, cols() - internal::get_runtime_value(cCols), internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return ConstBlockXpr(derived(), 0, cols() - cCols, cRows, cCols);
 }
 
-/// \returns an expression of a fixed-size top-right corner of \c *this.
+/// \returns an expression of a fixed-size top-right corner of *this.
 ///
 /// \tparam CRows the number of rows in the corner
 /// \tparam CCols the number of columns in the corner
@@ -178,7 +128,7 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topRightCorner() con
   return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), 0, cols() - CCols);
 }
 
-/// \returns an expression of a top-right corner of \c *this.
+/// \returns an expression of a top-right corner of *this.
 ///
 /// \tparam CRows number of rows in corner as specified at compile-time
 /// \tparam CCols number of columns in corner as specified at compile-time
@@ -212,51 +162,32 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topRightCorner(Index
 
 
 
-/// \returns an expression of a top-left corner of \c *this  with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of a top-left corner of *this.
 ///
 /// \param cRows the number of rows in the corner
 /// \param cCols the number of columns in the corner
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
 /// Example: \include MatrixBase_topLeftCorner_int_int.cpp
 /// Output: \verbinclude MatrixBase_topLeftCorner_int_int.out
 ///
-/// The number of rows \a blockRows and columns \a blockCols can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments. See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename FixedBlockXpr<...,...>::Type
-#endif
-topLeftCorner(NRowsType cRows, NColsType cCols)
+inline BlockXpr topLeftCorner(Index cRows, Index cCols)
 {
-  return typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, 0, internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return BlockXpr(derived(), 0, 0, cRows, cCols);
 }
 
 /// This is the const version of topLeftCorner(Index, Index).
-template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstFixedBlockXpr<...,...>::Type
-#endif
-topLeftCorner(NRowsType cRows, NColsType cCols) const
+inline const ConstBlockXpr topLeftCorner(Index cRows, Index cCols) const
 {
-  return typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, 0, internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return ConstBlockXpr(derived(), 0, 0, cRows, cCols);
 }
 
-/// \returns an expression of a fixed-size top-left corner of \c *this.
+/// \returns an expression of a fixed-size top-left corner of *this.
 ///
 /// The template parameters CRows and CCols are the number of rows and columns in the corner.
 ///
@@ -265,7 +196,7 @@ topLeftCorner(NRowsType cRows, NColsType cCols) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
@@ -282,7 +213,7 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topLeftCorner() cons
   return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), 0, 0);
 }
 
-/// \returns an expression of a top-left corner of \c *this.
+/// \returns an expression of a top-left corner of *this.
 ///
 /// \tparam CRows number of rows in corner as specified at compile-time
 /// \tparam CCols number of columns in corner as specified at compile-time
@@ -316,53 +247,32 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type topLeftCorner(Index
 
 
 
-/// \returns an expression of a bottom-right corner of \c *this  with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of a bottom-right corner of *this.
 ///
 /// \param cRows the number of rows in the corner
 /// \param cCols the number of columns in the corner
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
 /// Example: \include MatrixBase_bottomRightCorner_int_int.cpp
 /// Output: \verbinclude MatrixBase_bottomRightCorner_int_int.out
 ///
-/// The number of rows \a blockRows and columns \a blockCols can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments. See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename FixedBlockXpr<...,...>::Type
-#endif
-bottomRightCorner(NRowsType cRows, NColsType cCols)
+inline BlockXpr bottomRightCorner(Index cRows, Index cCols)
 {
-  return typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), rows() - internal::get_runtime_value(cRows), cols() - internal::get_runtime_value(cCols),
-                        internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return BlockXpr(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
-/// This is the const version of bottomRightCorner(NRowsType, NColsType).
-template<typename NRowsType, typename NColsType>
+/// This is the const version of bottomRightCorner(Index, Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstFixedBlockXpr<...,...>::Type
-#endif
-bottomRightCorner(NRowsType cRows, NColsType cCols) const
+inline const ConstBlockXpr bottomRightCorner(Index cRows, Index cCols) const
 {
-  return typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), rows() - internal::get_runtime_value(cRows), cols() - internal::get_runtime_value(cCols),
-                        internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return ConstBlockXpr(derived(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
-/// \returns an expression of a fixed-size bottom-right corner of \c *this.
+/// \returns an expression of a fixed-size bottom-right corner of *this.
 ///
 /// The template parameters CRows and CCols are the number of rows and columns in the corner.
 ///
@@ -371,7 +281,7 @@ bottomRightCorner(NRowsType cRows, NColsType cCols) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
@@ -388,7 +298,7 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomRightCorner()
   return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), rows() - CRows, cols() - CCols);
 }
 
-/// \returns an expression of a bottom-right corner of \c *this.
+/// \returns an expression of a bottom-right corner of *this.
 ///
 /// \tparam CRows number of rows in corner as specified at compile-time
 /// \tparam CCols number of columns in corner as specified at compile-time
@@ -422,53 +332,32 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomRightCorner(In
 
 
 
-/// \returns an expression of a bottom-left corner of \c *this  with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of a bottom-left corner of *this.
 ///
 /// \param cRows the number of rows in the corner
 /// \param cCols the number of columns in the corner
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
 /// Example: \include MatrixBase_bottomLeftCorner_int_int.cpp
 /// Output: \verbinclude MatrixBase_bottomLeftCorner_int_int.out
 ///
-/// The number of rows \a blockRows and columns \a blockCols can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments. See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType, typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename FixedBlockXpr<...,...>::Type
-#endif
-bottomLeftCorner(NRowsType cRows, NColsType cCols)
+inline BlockXpr bottomLeftCorner(Index cRows, Index cCols)
 {
-  return typename FixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), rows() - internal::get_runtime_value(cRows), 0,
-                        internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return BlockXpr(derived(), rows() - cRows, 0, cRows, cCols);
 }
 
-/// This is the const version of bottomLeftCorner(NRowsType, NColsType).
-template<typename NRowsType, typename NColsType>
+/// This is the const version of bottomLeftCorner(Index, Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename ConstFixedBlockXpr<...,...>::Type
-#endif
-bottomLeftCorner(NRowsType cRows, NColsType cCols) const
+inline const ConstBlockXpr bottomLeftCorner(Index cRows, Index cCols) const
 {
-  return typename ConstFixedBlockXpr<internal::get_fixed_value<NRowsType>::value,internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), rows() - internal::get_runtime_value(cRows), 0,
-                        internal::get_runtime_value(cRows), internal::get_runtime_value(cCols));
+  return ConstBlockXpr(derived(), rows() - cRows, 0, cRows, cCols);
 }
 
-/// \returns an expression of a fixed-size bottom-left corner of \c *this.
+/// \returns an expression of a fixed-size bottom-left corner of *this.
 ///
 /// The template parameters CRows and CCols are the number of rows and columns in the corner.
 ///
@@ -477,7 +366,7 @@ bottomLeftCorner(NRowsType cRows, NColsType cCols) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int CRows, int CCols>
 EIGEN_DEVICE_FUNC
@@ -494,7 +383,7 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomLeftCorner() c
   return typename ConstFixedBlockXpr<CRows,CCols>::Type(derived(), rows() - CRows, 0);
 }
 
-/// \returns an expression of a bottom-left corner of \c *this.
+/// \returns an expression of a bottom-left corner of *this.
 ///
 /// \tparam CRows number of rows in corner as specified at compile-time
 /// \tparam CCols number of columns in corner as specified at compile-time
@@ -528,50 +417,31 @@ inline const typename ConstFixedBlockXpr<CRows,CCols>::Type bottomLeftCorner(Ind
 
 
 
-/// \returns a block consisting of the top rows of \c *this.
+/// \returns a block consisting of the top rows of *this.
 ///
 /// \param n the number of rows in the block
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
 ///
 /// Example: \include MatrixBase_topRows_int.cpp
 /// Output: \verbinclude MatrixBase_topRows_int.out
 ///
-/// The number of rows \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(row-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename NRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-#else
-inline typename NRowsBlockXpr<...>::Type
-#endif
-topRows(NRowsType n)
+inline RowsBlockXpr topRows(Index n)
 {
-  return typename NRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-            (derived(), 0, 0, internal::get_runtime_value(n), cols());
+  return RowsBlockXpr(derived(), 0, 0, n, cols());
 }
 
-/// This is the const version of topRows(NRowsType).
-template<typename NRowsType>
+/// This is the const version of topRows(Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstNRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-#else
-inline const typename ConstNRowsBlockXpr<...>::Type
-#endif
-topRows(NRowsType n) const
+inline ConstRowsBlockXpr topRows(Index n) const
 {
-  return typename ConstNRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-            (derived(), 0, 0, internal::get_runtime_value(n), cols());
+  return ConstRowsBlockXpr(derived(), 0, 0, n, cols());
 }
 
-/// \returns a block consisting of the top rows of \c *this.
+/// \returns a block consisting of the top rows of *this.
 ///
 /// \tparam N the number of rows in the block as specified at compile-time
 /// \param n the number of rows in the block as specified at run-time
@@ -584,7 +454,7 @@ topRows(NRowsType n) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(row-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -603,50 +473,31 @@ inline typename ConstNRowsBlockXpr<N>::Type topRows(Index n = N) const
 
 
 
-/// \returns a block consisting of the bottom rows of \c *this.
+/// \returns a block consisting of the bottom rows of *this.
 ///
 /// \param n the number of rows in the block
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
 ///
 /// Example: \include MatrixBase_bottomRows_int.cpp
 /// Output: \verbinclude MatrixBase_bottomRows_int.out
 ///
-/// The number of rows \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(row-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename NRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-#else
-inline typename NRowsBlockXpr<...>::Type
-#endif
-bottomRows(NRowsType n)
+inline RowsBlockXpr bottomRows(Index n)
 {
-  return typename NRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-            (derived(), rows() - internal::get_runtime_value(n), 0, internal::get_runtime_value(n), cols());
+  return RowsBlockXpr(derived(), rows() - n, 0, n, cols());
 }
 
-/// This is the const version of bottomRows(NRowsType).
-template<typename NRowsType>
+/// This is the const version of bottomRows(Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstNRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-#else
-inline const typename ConstNRowsBlockXpr<...>::Type
-#endif
-bottomRows(NRowsType n) const
+inline ConstRowsBlockXpr bottomRows(Index n) const
 {
-  return typename ConstNRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-            (derived(), rows() - internal::get_runtime_value(n), 0, internal::get_runtime_value(n), cols());
+  return ConstRowsBlockXpr(derived(), rows() - n, 0, n, cols());
 }
 
-/// \returns a block consisting of the bottom rows of \c *this.
+/// \returns a block consisting of the bottom rows of *this.
 ///
 /// \tparam N the number of rows in the block as specified at compile-time
 /// \param n the number of rows in the block as specified at run-time
@@ -659,7 +510,7 @@ bottomRows(NRowsType n) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(row-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -678,51 +529,32 @@ inline typename ConstNRowsBlockXpr<N>::Type bottomRows(Index n = N) const
 
 
 
-/// \returns a block consisting of a range of rows of \c *this.
+/// \returns a block consisting of a range of rows of *this.
 ///
 /// \param startRow the index of the first row in the block
 /// \param n the number of rows in the block
-/// \tparam NRowsType the type of the value handling the number of rows in the block, typically Index.
 ///
 /// Example: \include DenseBase_middleRows_int.cpp
 /// Output: \verbinclude DenseBase_middleRows_int.out
 ///
-/// The number of rows \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(row-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NRowsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename NRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-#else
-inline typename NRowsBlockXpr<...>::Type
-#endif
-middleRows(Index startRow, NRowsType n)
+inline RowsBlockXpr middleRows(Index startRow, Index n)
 {
-  return typename NRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-            (derived(), startRow, 0, internal::get_runtime_value(n), cols());
+  return RowsBlockXpr(derived(), startRow, 0, n, cols());
 }
 
-/// This is the const version of middleRows(Index,NRowsType).
-template<typename NRowsType>
+/// This is the const version of middleRows(Index,Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstNRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-#else
-inline const typename ConstNRowsBlockXpr<...>::Type
-#endif
-middleRows(Index startRow, NRowsType n) const
+inline ConstRowsBlockXpr middleRows(Index startRow, Index n) const
 {
-  return typename ConstNRowsBlockXpr<internal::get_fixed_value<NRowsType>::value>::Type
-            (derived(), startRow, 0, internal::get_runtime_value(n), cols());
+  return ConstRowsBlockXpr(derived(), startRow, 0, n, cols());
 }
 
-/// \returns a block consisting of a range of rows of \c *this.
+/// \returns a block consisting of a range of rows of *this.
 ///
 /// \tparam N the number of rows in the block as specified at compile-time
 /// \param startRow the index of the first row in the block
@@ -736,7 +568,7 @@ middleRows(Index startRow, NRowsType n) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(row-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -755,50 +587,31 @@ inline typename ConstNRowsBlockXpr<N>::Type middleRows(Index startRow, Index n =
 
 
 
-/// \returns a block consisting of the left columns of \c *this.
+/// \returns a block consisting of the left columns of *this.
 ///
 /// \param n the number of columns in the block
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
 /// Example: \include MatrixBase_leftCols_int.cpp
 /// Output: \verbinclude MatrixBase_leftCols_int.out
 ///
-/// The number of columns \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(column-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename NColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename NColsBlockXpr<...>::Type
-#endif
-leftCols(NColsType n)
+inline ColsBlockXpr leftCols(Index n)
 {
-  return typename NColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, 0, rows(), internal::get_runtime_value(n));
+  return ColsBlockXpr(derived(), 0, 0, rows(), n);
 }
 
-/// This is the const version of leftCols(NColsType).
-template<typename NColsType>
+/// This is the const version of leftCols(Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstNColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstNColsBlockXpr<...>::Type
-#endif
-leftCols(NColsType n) const
+inline ConstColsBlockXpr leftCols(Index n) const
 {
-  return typename ConstNColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, 0, rows(), internal::get_runtime_value(n));
+  return ConstColsBlockXpr(derived(), 0, 0, rows(), n);
 }
 
-/// \returns a block consisting of the left columns of \c *this.
+/// \returns a block consisting of the left columns of *this.
 ///
 /// \tparam N the number of columns in the block as specified at compile-time
 /// \param n the number of columns in the block as specified at run-time
@@ -811,7 +624,7 @@ leftCols(NColsType n) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(column-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -830,50 +643,31 @@ inline typename ConstNColsBlockXpr<N>::Type leftCols(Index n = N) const
 
 
 
-/// \returns a block consisting of the right columns of \c *this.
+/// \returns a block consisting of the right columns of *this.
 ///
 /// \param n the number of columns in the block
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
 /// Example: \include MatrixBase_rightCols_int.cpp
 /// Output: \verbinclude MatrixBase_rightCols_int.out
 ///
-/// The number of columns \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(column-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename NColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename NColsBlockXpr<...>::Type
-#endif
-rightCols(NColsType n)
+inline ColsBlockXpr rightCols(Index n)
 {
-  return typename NColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, cols() - internal::get_runtime_value(n), rows(), internal::get_runtime_value(n));
+  return ColsBlockXpr(derived(), 0, cols() - n, rows(), n);
 }
 
-/// This is the const version of rightCols(NColsType).
-template<typename NColsType>
+/// This is the const version of rightCols(Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstNColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstNColsBlockXpr<...>::Type
-#endif
-rightCols(NColsType n) const
+inline ConstColsBlockXpr rightCols(Index n) const
 {
-  return typename ConstNColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, cols() - internal::get_runtime_value(n), rows(), internal::get_runtime_value(n));
+  return ConstColsBlockXpr(derived(), 0, cols() - n, rows(), n);
 }
 
-/// \returns a block consisting of the right columns of \c *this.
+/// \returns a block consisting of the right columns of *this.
 ///
 /// \tparam N the number of columns in the block as specified at compile-time
 /// \param n the number of columns in the block as specified at run-time
@@ -886,7 +680,7 @@ rightCols(NColsType n) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(column-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -905,51 +699,32 @@ inline typename ConstNColsBlockXpr<N>::Type rightCols(Index n = N) const
 
 
 
-/// \returns a block consisting of a range of columns of \c *this.
+/// \returns a block consisting of a range of columns of *this.
 ///
 /// \param startCol the index of the first column in the block
 /// \param numCols the number of columns in the block
-/// \tparam NColsType the type of the value handling the number of columns in the block, typically Index.
 ///
 /// Example: \include DenseBase_middleCols_int.cpp
 /// Output: \verbinclude DenseBase_middleCols_int.out
 ///
-/// The number of columns \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(column-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
-template<typename NColsType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename NColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline typename NColsBlockXpr<...>::Type
-#endif
-middleCols(Index startCol, NColsType numCols)
+inline ColsBlockXpr middleCols(Index startCol, Index numCols)
 {
-  return typename NColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, startCol, rows(), internal::get_runtime_value(numCols));
+  return ColsBlockXpr(derived(), 0, startCol, rows(), numCols);
 }
 
-/// This is the const version of middleCols(Index,NColsType).
-template<typename NColsType>
+/// This is the const version of middleCols(Index,Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstNColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-#else
-inline const typename ConstNColsBlockXpr<...>::Type
-#endif
-middleCols(Index startCol, NColsType numCols) const
+inline ConstColsBlockXpr middleCols(Index startCol, Index numCols) const
 {
-  return typename ConstNColsBlockXpr<internal::get_fixed_value<NColsType>::value>::Type
-            (derived(), 0, startCol, rows(), internal::get_runtime_value(numCols));
+  return ConstColsBlockXpr(derived(), 0, startCol, rows(), numCols);
 }
 
-/// \returns a block consisting of a range of columns of \c *this.
+/// \returns a block consisting of a range of columns of *this.
 ///
 /// \tparam N the number of columns in the block as specified at compile-time
 /// \param startCol the index of the first column in the block
@@ -963,7 +738,7 @@ middleCols(Index startCol, NColsType numCols) const
 ///
 EIGEN_DOC_BLOCK_ADDONS_INNER_PANEL_IF(column-major)
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -982,7 +757,7 @@ inline typename ConstNColsBlockXpr<N>::Type middleCols(Index startCol, Index n =
 
 
 
-/// \returns a fixed-size expression of a block of \c *this.
+/// \returns a fixed-size expression of a block in *this.
 ///
 /// The template parameters \a NRows and \a NCols are the number of
 /// rows and columns in the block.
@@ -993,18 +768,12 @@ inline typename ConstNColsBlockXpr<N>::Type middleCols(Index startCol, Index n =
 /// Example: \include MatrixBase_block_int_int.cpp
 /// Output: \verbinclude MatrixBase_block_int_int.out
 ///
-/// \note The usage of of this overload is discouraged from %Eigen 3.4, better used the generic
-/// block(Index,Index,NRowsType,NColsType), here is the one-to-one equivalence:
-/// \code
-/// mat.template block<NRows,NCols>(i,j)  <-->  mat.block(i,j,fix<NRows>,fix<NCols>)
-/// \endcode
-///
 /// \note since block is a templated member, the keyword template has to be used
 /// if the matrix type is also a template parameter: \code m.template block<3,3>(1,1); \endcode
 ///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int NRows, int NCols>
 EIGEN_DEVICE_FUNC
@@ -1021,7 +790,7 @@ inline const typename ConstFixedBlockXpr<NRows,NCols>::Type block(Index startRow
   return typename ConstFixedBlockXpr<NRows,NCols>::Type(derived(), startRow, startCol);
 }
 
-/// \returns an expression of a block of \c *this.
+/// \returns an expression of a block in *this.
 ///
 /// \tparam NRows number of rows in block as specified at compile-time
 /// \tparam NCols number of columns in block as specified at compile-time
@@ -1038,19 +807,9 @@ inline const typename ConstFixedBlockXpr<NRows,NCols>::Type block(Index startRow
 /// Example: \include MatrixBase_template_int_int_block_int_int_int_int.cpp
 /// Output: \verbinclude MatrixBase_template_int_int_block_int_int_int_int.cpp
 ///
-/// \note The usage of of this overload is discouraged from %Eigen 3.4, better used the generic
-/// block(Index,Index,NRowsType,NColsType), here is the one-to-one complete equivalence:
-/// \code
-/// mat.template block<NRows,NCols>(i,j,rows,cols)     <-->  mat.block(i,j,fix<NRows>(rows),fix<NCols>(cols))
-/// \endcode
-/// If we known that, e.g., NRows==Dynamic and NCols!=Dynamic, then the equivalence becomes:
-/// \code
-/// mat.template block<Dynamic,NCols>(i,j,rows,NCols)  <-->  mat.block(i,j,rows,fix<NCols>)
-/// \endcode
-///
 EIGEN_DOC_BLOCK_ADDONS_NOT_INNER_PANEL
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), class Block
+/// \sa class Block, block(Index,Index,Index,Index)
 ///
 template<int NRows, int NCols>
 inline typename FixedBlockXpr<NRows,NCols>::Type block(Index startRow, Index startCol,
@@ -1067,7 +826,7 @@ inline const typename ConstFixedBlockXpr<NRows,NCols>::Type block(Index startRow
   return typename ConstFixedBlockXpr<NRows,NCols>::Type(derived(), startRow, startCol, blockRows, blockCols);
 }
 
-/// \returns an expression of the \a i-th column of \c *this. Note that the numbering starts at 0.
+/// \returns an expression of the \a i-th column of *this. Note that the numbering starts at 0.
 ///
 /// Example: \include MatrixBase_col.cpp
 /// Output: \verbinclude MatrixBase_col.out
@@ -1088,7 +847,7 @@ inline ConstColXpr col(Index i) const
   return ConstColXpr(derived(), i);
 }
 
-/// \returns an expression of the \a i-th row of \c *this. Note that the numbering starts at 0.
+/// \returns an expression of the \a i-th row of *this. Note that the numbering starts at 0.
 ///
 /// Example: \include MatrixBase_row.cpp
 /// Output: \verbinclude MatrixBase_row.out
@@ -1109,153 +868,96 @@ inline ConstRowXpr row(Index i) const
   return ConstRowXpr(derived(), i);
 }
 
-/// \returns an expression of a segment (i.e. a vector block) in \c *this with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of a segment (i.e. a vector block) in *this.
 ///
 /// \only_for_vectors
 ///
 /// \param start the first coefficient in the segment
 /// \param n the number of coefficients in the segment
-/// \tparam NType the type of the value handling the number of coefficients in the segment, typically Index.
 ///
 /// Example: \include MatrixBase_segment_int_int.cpp
 /// Output: \verbinclude MatrixBase_segment_int_int.out
 ///
-/// The number of coefficients \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
-/// \note Even in the case that the returned expression has dynamic size, in the case
+/// \note Even though the returned expression has dynamic size, in the case
 /// when it is applied to a fixed-size vector, it inherits a fixed maximal size,
 /// which means that evaluating it does not cause a dynamic memory allocation.
 ///
-/// \sa block(Index,Index,NRowsType,NColsType), fix<N>, fix<N>(int), class Block
+/// \sa class Block, segment(Index)
 ///
-template<typename NType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-#else
-inline typename FixedSegmentReturnType<...>::Type
-#endif
-segment(Index start, NType n)
+inline SegmentReturnType segment(Index start, Index n)
 {
   EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-  return typename FixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-            (derived(), start, internal::get_runtime_value(n));
+  return SegmentReturnType(derived(), start, n);
 }
 
 
-/// This is the const version of segment(Index,NType).
-template<typename NType>
+/// This is the const version of segment(Index,Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-#else
-inline const typename ConstFixedSegmentReturnType<...>::Type
-#endif
-segment(Index start, NType n) const
+inline ConstSegmentReturnType segment(Index start, Index n) const
 {
   EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-  return typename ConstFixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-            (derived(), start, internal::get_runtime_value(n));
+  return ConstSegmentReturnType(derived(), start, n);
 }
 
-/// \returns an expression of the first coefficients of \c *this with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of the first coefficients of *this.
 ///
 /// \only_for_vectors
 ///
 /// \param n the number of coefficients in the segment
-/// \tparam NType the type of the value handling the number of coefficients in the segment, typically Index.
 ///
 /// Example: \include MatrixBase_start_int.cpp
 /// Output: \verbinclude MatrixBase_start_int.out
 ///
-/// The number of coefficients \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
-/// \note Even in the case that the returned expression has dynamic size, in the case
+/// \note Even though the returned expression has dynamic size, in the case
 /// when it is applied to a fixed-size vector, it inherits a fixed maximal size,
 /// which means that evaluating it does not cause a dynamic memory allocation.
 ///
 /// \sa class Block, block(Index,Index)
 ///
-template<typename NType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-#else
-inline typename FixedSegmentReturnType<...>::Type
-#endif
-head(NType n)
+inline SegmentReturnType head(Index n)
 {
   EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-  return typename FixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-              (derived(), 0, internal::get_runtime_value(n));
+  return SegmentReturnType(derived(), 0, n);
 }
 
-/// This is the const version of head(NType).
-template<typename NType>
+/// This is the const version of head(Index).
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-#else
-inline const typename ConstFixedSegmentReturnType<...>::Type
-#endif
-head(NType n) const
+inline ConstSegmentReturnType head(Index n) const
 {
   EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-  return typename ConstFixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-            (derived(), 0, internal::get_runtime_value(n));
+  return ConstSegmentReturnType(derived(), 0, n);
 }
 
-/// \returns an expression of a last coefficients of \c *this with either dynamic or fixed sizes.
+/// \returns a dynamic-size expression of the last coefficients of *this.
 ///
 /// \only_for_vectors
 ///
 /// \param n the number of coefficients in the segment
-/// \tparam NType the type of the value handling the number of coefficients in the segment, typically Index.
 ///
 /// Example: \include MatrixBase_end_int.cpp
 /// Output: \verbinclude MatrixBase_end_int.out
 ///
-/// The number of coefficients \a n can also be specified at compile-time by passing Eigen::fix<N>,
-/// or Eigen::fix<N>(n) as arguments.
-/// See \link block(Index,Index,NRowsType,NColsType) block() \endlink for the details.
-///
-/// \note Even in the case that the returned expression has dynamic size, in the case
+/// \note Even though the returned expression has dynamic size, in the case
 /// when it is applied to a fixed-size vector, it inherits a fixed maximal size,
 /// which means that evaluating it does not cause a dynamic memory allocation.
 ///
 /// \sa class Block, block(Index,Index)
 ///
-template<typename NType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline typename FixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-#else
-inline typename FixedSegmentReturnType<...>::Type
-#endif
-tail(NType n)
+inline SegmentReturnType tail(Index n)
 {
   EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-  return typename FixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-            (derived(), this->size() - internal::get_runtime_value(n), internal::get_runtime_value(n));
+  return SegmentReturnType(derived(), this->size() - n, n);
 }
 
 /// This is the const version of tail(Index).
-template<typename NType>
 EIGEN_DEVICE_FUNC
-#ifndef EIGEN_PARSED_BY_DOXYGEN
-inline const typename ConstFixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-#else
-inline const typename ConstFixedSegmentReturnType<...>::Type
-#endif
-tail(NType n) const
+inline ConstSegmentReturnType tail(Index n) const
 {
   EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-  return typename ConstFixedSegmentReturnType<internal::get_fixed_value<NType>::value>::Type
-            (derived(), this->size() - internal::get_runtime_value(n), internal::get_runtime_value(n));
+  return ConstSegmentReturnType(derived(), this->size() - n, n);
 }
 
 /// \returns a fixed-size expression of a segment (i.e. a vector block) in \c *this
@@ -1272,7 +974,7 @@ tail(NType n) const
 /// Example: \include MatrixBase_template_int_segment.cpp
 /// Output: \verbinclude MatrixBase_template_int_segment.out
 ///
-/// \sa segment(Index,NType), class Block
+/// \sa class Block
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -1291,7 +993,7 @@ inline typename ConstFixedSegmentReturnType<N>::Type segment(Index start, Index
   return typename ConstFixedSegmentReturnType<N>::Type(derived(), start, n);
 }
 
-/// \returns a fixed-size expression of the first coefficients of \c *this.
+/// \returns a fixed-size expression of the first coefficients of *this.
 ///
 /// \only_for_vectors
 ///
@@ -1304,7 +1006,7 @@ inline typename ConstFixedSegmentReturnType<N>::Type segment(Index start, Index
 /// Example: \include MatrixBase_template_int_start.cpp
 /// Output: \verbinclude MatrixBase_template_int_start.out
 ///
-/// \sa head(NType), class Block
+/// \sa class Block
 ///
 template<int N>
 EIGEN_DEVICE_FUNC
@@ -1323,7 +1025,7 @@ inline typename ConstFixedSegmentReturnType<N>::Type head(Index n = N) const
   return typename ConstFixedSegmentReturnType<N>::Type(derived(), 0, n);
 }
 
-/// \returns a fixed-size expression of the last coefficients of \c *this.
+/// \returns a fixed-size expression of the last coefficients of *this.
 ///
 /// \only_for_vectors
 ///
@@ -1336,7 +1038,7 @@ inline typename ConstFixedSegmentReturnType<N>::Type head(Index n = N) const
 /// Example: \include MatrixBase_template_int_end.cpp
 /// Output: \verbinclude MatrixBase_template_int_end.out
 ///
-/// \sa tail(NType), class Block
+/// \sa class Block
 ///
 template<int N>
 EIGEN_DEVICE_FUNC