Patch by Gael Guennebaud: unify fixed-size and dynamic-size Block

expressions, update documentation.

Eigen/Core

@@ -6,8 +6,8 @@
 
 namespace Eigen {
 
-#include "src/Core/ForwardDeclarations.h"
 #include "src/Core/Util.h"
+#include "src/Core/ForwardDeclarations.h"
 #include "src/Core/NumTraits.h"
 #include "src/Core/MathFunctions.h"
 #include "src/Core/MatrixBase.h"
@@ -25,7 +25,6 @@ namespace Eigen {
 #include "src/Core/Product.h"
 #include "src/Core/Row.h"
 #include "src/Core/Column.h"
-#include "src/Core/FixedBlock.h"
 #include "src/Core/Block.h"
 #include "src/Core/Minor.h"
 #include "src/Core/Transpose.h"

Eigen/src/Core/Block.h

@@ -27,19 +27,21 @@
 
 /** \class Block
   *
-  * \brief Expression of a dynamic-size block
+  * \brief Expression of a fixed-size or dynamic-size block
   *
   * \param MatrixType the type of the object in which we are taking a block
+  * \param BlockRows the number of rows of the block we are taking at compile time (optional)
+  * \param BlockCols the number of columns of the block we are taking at compile time (optional)
   *
-  * This class represents an expression of a dynamic-size block. It is the return
-  * type of MatrixBase::block(int,int,int,int) and most of the time this is the only way it
-  * is used.
+  * This class represents an expression of either a fixed-size or dynamic-size block. It is the return
+  * type of MatrixBase::block(int,int,int,int) and MatrixBase::block<int,int>(int,int) and
+  * most of the time this is the only way it is used.
   *
-  * However, if you want to directly maniputate dynamic-size block expressions,
+  * However, if you want to directly maniputate block expressions,
   * for instance if you want to write a function returning such an expression, you
   * will need to use this class.
   *
-  * Here is an example illustrating this:
+  * Here is an example illustrating the dynamic case:
   * \include class_Block.cpp
   * Output: \verbinclude class_Block.out
   *
@@ -47,10 +49,16 @@
   * has fixed size, this expression inherits a fixed maximal size which means that evaluating
   * it does not cause a dynamic memory allocation.
   *
-  * \sa MatrixBase::block(int,int,int,int), class VectorBlock
+  * Here is an example illustrating the fixed-size case:
+  * \include class_FixedBlock.cpp
+  * Output: \verbinclude class_FixedBlock.out
+  *
+  * \sa MatrixBase::block(int,int,int,int), MatrixBase::block(int,int), class VectorBlock
   */
-template<typename MatrixType> class Block
-  : public MatrixBase<typename MatrixType::Scalar, Block<MatrixType> >
+template<typename MatrixType,
+    int BlockRows/*=Dynamic*/, int BlockCols/*=Dynamic*/> class Block
+  : public MatrixBase<typename MatrixType::Scalar,
+                      Block<MatrixType, BlockRows, BlockCols> >
 {
   public:
     typedef typename MatrixType::Scalar Scalar;
@@ -58,12 +66,26 @@ template<typename MatrixType> class Block
     friend class MatrixBase<Scalar, Block>;
     typedef MatrixBase<Scalar, Block> Base;
 
+    /** Fixed-size constructor
+      */
+    Block(const MatRef& matrix, int startRow, int startCol)
+      : m_matrix(matrix), m_startRow(startRow), m_startCol(startCol)
+    {
+      assert(RowsAtCompileTime!=Dynamic && RowsAtCompileTime!=Dynamic);
+      assert(startRow >= 0 && BlockRows >= 1 && startRow + BlockRows <= matrix.rows()
+          && startCol >= 0 && BlockCols >= 1 && startCol + BlockCols <= matrix.cols());
+    }
+    
+    /** Dynamic-size constructor
+      */
     Block(const MatRef& matrix,
           int startRow, int startCol,
           int blockRows, int blockCols)
       : m_matrix(matrix), m_startRow(startRow), m_startCol(startCol),
                           m_blockRows(blockRows), m_blockCols(blockCols)
     {
+      assert((RowsAtCompileTime==Dynamic || RowsAtCompileTime==1)
+          && (ColsAtCompileTime==Dynamic || ColsAtCompileTime==1));
       assert(startRow >= 0 && blockRows >= 1 && startRow + blockRows <= matrix.rows()
           && startCol >= 0 && blockCols >= 1 && startCol + blockCols <= matrix.cols());
     }
@@ -71,11 +93,13 @@ template<typename MatrixType> class Block
     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Block)
     
   private:
-    enum {
-      RowsAtCompileTime = MatrixType::Traits::RowsAtCompileTime == 1 ? 1 : Dynamic,
-      ColsAtCompileTime = MatrixType::Traits::ColsAtCompileTime == 1 ? 1 : Dynamic,
-      MaxRowsAtCompileTime = RowsAtCompileTime == 1 ? 1 : MatrixType::Traits::MaxRowsAtCompileTime,
-      MaxColsAtCompileTime = ColsAtCompileTime == 1 ? 1 : MatrixType::Traits::MaxColsAtCompileTime
+    enum{
+      RowsAtCompileTime = MatrixType::Traits::RowsAtCompileTime == 1 ? 1 : BlockRows,
+      ColsAtCompileTime = MatrixType::Traits::ColsAtCompileTime == 1 ? 1 : BlockCols,
+      MaxRowsAtCompileTime = RowsAtCompileTime == 1 ? 1
+        : (BlockRows==Dynamic ? MatrixType::Traits::MaxRowsAtCompileTime : BlockRows),
+      MaxColsAtCompileTime = ColsAtCompileTime == 1 ? 1
+        : (BlockCols==Dynamic ? MatrixType::Traits::MaxColsAtCompileTime : BlockCols)
     };
 
     const Block& _ref() const { return *this; }
@@ -93,11 +117,10 @@ template<typename MatrixType> class Block
     }
     
   protected:
+
     MatRef m_matrix;
-    IntAtRunTimeIfDynamic<MatrixType::Traits::RowsAtCompileTime == 1 ? 0 : Dynamic>
-      m_startRow;
-    IntAtRunTimeIfDynamic<MatrixType::Traits::ColsAtCompileTime == 1 ? 0 : Dynamic>
-      m_startCol;
+    IntAtRunTimeIfDynamic<MatrixType::Traits::RowsAtCompileTime == 1 ? 0 : Dynamic> m_startRow;
+    IntAtRunTimeIfDynamic<MatrixType::Traits::ColsAtCompileTime == 1 ? 0 : Dynamic> m_startCol;
     IntAtRunTimeIfDynamic<RowsAtCompileTime> m_blockRows;
     IntAtRunTimeIfDynamic<ColsAtCompileTime> m_blockCols;
 };
@@ -116,7 +139,7 @@ template<typename MatrixType> class Block
   * 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.
   *
-  * \sa class Block, fixedBlock(int,int)
+  * \sa class Block, block(int,int)
   */
 template<typename Scalar, typename Derived>
 Block<Derived> MatrixBase<Scalar, Derived>
@@ -147,7 +170,7 @@ const Block<Derived> MatrixBase<Scalar, Derived>
   * 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, fixedBlock(int)
+  * \sa class Block, block(int)
   */
 template<typename Scalar, typename Derived>
 Block<Derived> MatrixBase<Scalar, Derived>
@@ -293,4 +316,34 @@ const Block<Derived> MatrixBase<Scalar, Derived>
     return Block<Derived>(ref(), rows() - cRows, cols() - cCols, cRows, cCols);
 }
 
+/** \returns a fixed-size expression of a block in *this.
+  *
+  * The template parameters \a BlockRows and \a BlockCols are the number of
+  * rows and columns in the block.
+  *
+  * \param startRow the first row in the block
+  * \param startCol the first column in the block
+  *
+  * Example: \include MatrixBase_block_int_int.cpp
+  * Output: \verbinclude MatrixBase_block_int_int.out
+  *
+  * \sa class Block, block(int,int,int,int)
+  */
+template<typename Scalar, typename Derived>
+template<int BlockRows, int BlockCols>
+Block<Derived, BlockRows, BlockCols> MatrixBase<Scalar, Derived>
+  ::block(int startRow, int startCol)
+{
+  return Block<Derived, BlockRows, BlockCols>(ref(), startRow, startCol);
+}
+
+/** This is the const version of block<>(int, int). */
+template<typename Scalar, typename Derived>
+template<int BlockRows, int BlockCols>
+const Block<Derived, BlockRows, BlockCols> MatrixBase<Scalar, Derived>
+  ::block(int startRow, int startCol) const
+{
+  return Block<Derived, BlockRows, BlockCols>(ref(), startRow, startCol);
+}
+
 #endif // EIGEN_BLOCK_H

Eigen/src/Core/ForwardDeclarations.h

@@ -31,8 +31,7 @@ template<typename NewScalar, typename MatrixType> class Cast;
 template<typename MatrixType> class Row;
 template<typename MatrixType> class Column;
 template<typename MatrixType> class Minor;
-template<typename MatrixType> class Block;
-template<typename MatrixType, int BlockRows, int BlockCols> class FixedBlock;
+template<typename MatrixType, int BlockRows=Dynamic, int BlockCols=Dynamic> class Block;
 template<typename MatrixType> class Transpose;
 template<typename MatrixType> class Conjugate;
 template<typename MatrixType> class Opposite;

Eigen/src/Core/MatrixBase.h

@@ -200,9 +200,9 @@ template<typename Scalar, typename Derived> class MatrixBase
     const Block<Derived> corner(CornerType type, int cRows, int cCols) const;
 
     template<int BlockRows, int BlockCols>
-    FixedBlock<Derived, BlockRows, BlockCols> fixedBlock(int startRow, int startCol);
+    Block<Derived, BlockRows, BlockCols> block(int startRow, int startCol);
     template<int BlockRows, int BlockCols>
-    const FixedBlock<Derived, BlockRows, BlockCols> fixedBlock(int startRow, int startCol) const;
+    const Block<Derived, BlockRows, BlockCols> block(int startRow, int startCol) const;
 
     Transpose<Derived> transpose();
     const Transpose<Derived> transpose() const;

doc/examples/class_FixedBlock.cpp

@@ -3,17 +3,17 @@ USING_PART_OF_NAMESPACE_EIGEN
 using namespace std;
 
 template<typename Scalar, typename Derived>
-Eigen::FixedBlock<Derived, 2, 2>
+Eigen::Block<Derived, 2, 2>
 topLeft2x2Corner(MatrixBase<Scalar, Derived>& m)
 {
-  return Eigen::FixedBlock<Derived, 2, 2>(m.ref(), 0, 0);
+  return Eigen::Block<Derived, 2, 2>(m.ref(), 0, 0);
 }
 
 template<typename Scalar, typename Derived>
-const Eigen::FixedBlock<Derived, 2, 2>
+const Eigen::Block<Derived, 2, 2>
 topLeft2x2Corner(const MatrixBase<Scalar, Derived>& m)
 {
-  return Eigen::FixedBlock<Derived, 2, 2>(m.ref(), 0, 0);
+  return Eigen::Block<Derived, 2, 2>(m.ref(), 0, 0);
 }
 
 int main(int, char**)

doc/snippets/MatrixBase_fixedBlock_int_int.cpp

@@ -1,5 +1,5 @@
 Matrix4d m = Vector4d(1,2,3,4).asDiagonal();
 cout << "Here is the matrix m:" << endl << m << endl;
-cout << "Here is m.fixedBlock<2, 2>(2, 2):" << endl << m.fixedBlock<2, 2>(2, 2) << endl;
-m.fixedBlock<2, 2>(2, 0) = m.fixedBlock<2, 2>(2, 2);
+cout << "Here is m.fixed<2, 2>(2, 2):" << endl << m.block<2, 2>(2, 2) << endl;
+m.block<2, 2>(2, 0) = m.block<2, 2>(2, 2);
 cout << "Now the matrix m is:" << endl << m << endl;

doc/snippets/MatrixBase_setIdentity.cpp

@@ -1,3 +1,3 @@
 Matrix4i m = Matrix4i::zero();
-m.fixedBlock<3,3>(1,0).setIdentity();
+m.block<3,3>(1,0).setIdentity();
 cout << m << endl;

doc/tutorial.cpp

@@ -18,13 +18,13 @@ int main(int, char **)
   // notice how we are mixing fixed-size and dynamic-size types.
   
   cout << "In the top-left block, we put the matrix m shown above." << endl;
-  m2.fixedBlock<2,2>(0,0) = m;
+  m2.block<2,2>(0,0) = m;
   cout << "In the bottom-left block, we put the matrix m*m, which is:" << endl << m*m << endl;
-  m2.fixedBlock<2,2>(2,0) = m * m;
+  m2.block<2,2>(2,0) = m * m;
   cout << "In the top-right block, we put the matrix m+m, which is:" << endl << m+m << endl;
-  m2.fixedBlock<2,2>(0,2) = m + m;
+  m2.block<2,2>(0,2) = m + m;
   cout << "In the bottom-right block, we put the matrix m-m, which is:" << endl << m-m << endl;
-  m2.fixedBlock<2,2>(2,2) = m - m;
+  m2.block<2,2>(2,2) = m - m;
   cout << "Now the 4x4 matrix m2 is:" << endl << m2 << endl;
   
   cout << "Row 0 of m2 is:" << endl << m2.row(0) << endl;

test/submatrices.cpp

@@ -29,7 +29,7 @@ namespace Eigen {
 template<typename MatrixType> void submatrices(const MatrixType& m)
 {
   /* this test covers the following files:
-     Row.h Column.h FixedBlock.h Block.h Minor.h DiagonalCoeffs.h
+     Row.h Column.h Block.h Minor.h DiagonalCoeffs.h
   */
   
   typedef typename MatrixType::Scalar Scalar;
@@ -103,17 +103,17 @@ void EigenTest::testSubmatrices()
     submatrices(MatrixXi(8, 12));
     submatrices(MatrixXcd(20, 20));
     
-    // test fixedBlock() separately as it is a template method so doesn't support
+    // test fixed block() separately as it is a template method so doesn't support
     // being called as a member of a class that is itself a template parameter
     // (at least as of g++ 4.2)
     Matrix<float, 6, 8> m = Matrix<float, 6, 8>::random();
     float s = ei_random<float>();
-    // test fixedBlock() as lvalue
-    m.fixedBlock<2,5>(1,1) *= s;
-    // test operator() on fixedBlock() both as constant and non-constant
-    m.fixedBlock<2,5>(1,1)(0, 3) = m.fixedBlock<2,5>(1,1)(1,2);
-    // check that fixedBlock() and block() agree
-    MatrixXf b = m.fixedBlock<3,2>(3,3);
+    // test fixed block() as lvalue
+    m.block<2,5>(1,1) *= s;
+    // test operator() on fixed block() both as constant and non-constant
+    m.block<2,5>(1,1)(0, 3) = m.block<2,5>(1,1)(1,2);
+    // check that fixed block() and block() agree
+    MatrixXf b = m.block<3,2>(3,3);
     VERIFY_IS_APPROX(b, m.block(3,3,3,2));
   }
 }