* implement the corner() API change: new methods topLeftCorner() etc

* get rid of BlockReturnType: it was not needed, and code was not always using it consistently anyway
* add topRows(), leftCols(), bottomRows(), rightCols()
* add corners unit-test covering all of that
* adapt docs, expand "porting from eigen 2 to 3"
* adapt Eigen2Support

8 files changed, 49 insertions, 161 deletions

diff --git a/doc/A05_PortingFrom2To3.dox b/doc/A05_PortingFrom2To3.dox
index 57f801f84..554ca7f2c 100644
--- a/doc/A05_PortingFrom2To3.dox
+++ b/doc/A05_PortingFrom2To3.dox
@@ -9,6 +9,7 @@ and to help porting an application from Eigen2 to Eigen3.
   - \ref CompatibilitySupport
   - \ref ChangeList
   - \ref CoefficientWiseOperations
+  - \ref Corners
   - \ref LazyVsNoalias
 
 \section CompatibilitySupport Eigen2 compatibility support
@@ -81,6 +82,34 @@ With Eigen2 you would have written:
 c = (a.cwise().abs().cwise().pow(3)).cwise() * (b.cwise().abs().cwise().sin());
 \endcode
 
+\section Corners Corners
+
+<table>
+<tr><td>Eigen 2</td><td>Eigen 3</td></tr>
+<tr><td>\code
+matrix.corner(TopLeft,r,c)
+matrix.corner(TopRight,r,c)
+matrix.corner(BottomLeft,r,c)
+matrix.corner(BottomRight,r,c)
+matrix.corner<r,c>(TopLeft)
+matrix.corner<r,c>(TopRight)
+matrix.corner<r,c>(BottomLeft)
+matrix.corner<r,c>(BottomRight)
+\endcode</td><td>\code
+matrix.topLeftCorner(r,c)
+matrix.topRightCorner(r,c)
+matrix.bottomLeftCorner(r,c)
+matrix.bottomRightCorner(r,c)
+matrix.topLeftCorner<r,c>()
+matrix.topRightCorner<r,c>()
+matrix.bottomLeftCorner<r,c>()
+matrix.bottomRightCorner<r,c>()
+\endcode</td>
+</tr>
+</table>
+
+Notice that Eigen3 also provides these new convenience methods: topRows(), bottomRows(), leftCols(), rightCols(). See in class DenseBase.
+
 \section LazyVsNoalias Lazy evaluation and noalias
 
 In Eigen all operations are performed in a lazy fashion except the matrix products which are always evaluated into a temporary by default.
diff --git a/doc/AsciiQuickReference.txt b/doc/AsciiQuickReference.txt
index 74de7344b..d2e973f5d 100644
--- a/doc/AsciiQuickReference.txt
+++ b/doc/AsciiQuickReference.txt
@@ -47,15 +47,14 @@ x.segment(i, n)                    // x(i+1 : i+n)
 x.segment<n>(i)                    // x(i+1 : i+n)
 P.block(i, j, rows, cols)          // P(i+1 : i+rows, j+1 : j+cols)
 P.block<rows, cols>(i, j)          // P(i+1 : i+rows, j+1 : j+cols)
-P.corner(TopLeft, rows, cols)      // P(1:rows, 1:cols)
-P.corner(TopRight, rows, cols)     // [m n]=size(P); P(1:rows, n-cols+1:n)
-P.corner(BottomLeft, rows, cols)   // [m n]=size(P); P(m-rows+1:m, 1:cols)
-P.corner(BottomRight, rows, cols)  // [m n]=size(P); P(m-rows+1:m, n-cols+1:n)
-P.corner<rows,cols>(TopLeft)       // P(1:rows, 1:cols)
-P.corner<rows,cols>(TopRight)      // [m n]=size(P); P(1:rows, n-cols+1:n)
-P.corner<rows,cols>(BottomLeft)    // [m n]=size(P); P(m-rows+1:m, 1:cols)
-P.corner<rows,cols>(BottomRight)   // [m n]=size(P); P(m-rows+1:m, n-cols+1:n)
-P.minor(i, j)                      // Something nasty.
+P.topLeftCorner(rows, cols)        // P(1:rows, 1:cols)
+P.topRightCorner(rows, cols)       // [m n]=size(P); P(1:rows, n-cols+1:n)
+P.bottomLeftCorner(rows, cols)     // [m n]=size(P); P(m-rows+1:m, 1:cols)
+P.bottomRightCorner(rows, cols)    // [m n]=size(P); P(m-rows+1:m, n-cols+1:n)
+P.topLeftCorner<rows,cols>()       // P(1:rows, 1:cols)
+P.topRightCorner<rows,cols>()      // [m n]=size(P); P(1:rows, n-cols+1:n)
+P.bottomLeftCorner<rows,cols>()    // [m n]=size(P); P(m-rows+1:m, 1:cols)
+P.bottomRightCorner<rows,cols>()   // [m n]=size(P); P(m-rows+1:m, n-cols+1:n)
 
 // Of particular note is Eigen's swap function which is highly optimized.
 // Eigen                           // Matlab
diff --git a/doc/C01_QuickStartGuide.dox b/doc/C01_QuickStartGuide.dox
index b346e2371..79705aa9d 100644
--- a/doc/C01_QuickStartGuide.dox
+++ b/doc/C01_QuickStartGuide.dox
@@ -577,29 +577,22 @@ Read-write access to sub-matrices:</td><td></td><td></td></tr>
       \link DenseBase::block(int,int) (more) \endlink</td>
   <td>the \c rows x \c cols sub-matrix \n starting from position (\c i,\c j)</td></tr><tr>
  <td>\code
- mat1.corner(TopLeft,rows,cols)
- mat1.corner(TopRight,rows,cols)
- mat1.corner(BottomLeft,rows,cols)
- mat1.corner(BottomRight,rows,cols)\endcode
- \link DenseBase::corner(CornerType,int,int) (more) \endlink</td>
+ mat1.topLeftCorner(rows,cols)
+ mat1.topRightCorner(rows,cols)
+ mat1.bottomLeftCorner(rows,cols)
+ mat1.bottomRightCorner(rows,cols)\endcode
  <td>\code
- mat1.corner<rows,cols>(TopLeft)
- mat1.corner<rows,cols>(TopRight)
- mat1.corner<rows,cols>(BottomLeft)
- mat1.corner<rows,cols>(BottomRight)\endcode
- \link DenseBase::corner(CornerType) (more) \endlink</td>
+ mat1.topLeftCorner<rows,cols>()
+ mat1.topRightCorner<rows,cols>()
+ mat1.bottomLeftCorner<rows,cols>()
+ mat1.bottomRightCorner<rows,cols>()\endcode
  <td>the \c rows x \c cols sub-matrix \n taken in one of the four corners</td></tr>
-<tr><td>\code
-mat4x4.minor(i,j) = mat3x3;
-mat3x3 = mat4x4.minor(i,j);\endcode
-</td><td></td><td>
-\link DenseBase::minor() minor \endlink (read-write)</td>
-</tr>
 </table>
 
 
 
-<a href="#" class="top">top</a>\section TutorialCoreDiagonalMatrices Diagonal matrices \matrixworld
+<a href="#" class="top">top</a>\section TutorialCoreDiagonalMatrices Diagonal matrices
+\matrixworld
 
 <table class="tutorial_code">
 <tr><td>
diff --git a/doc/C03_TutorialGeometry.dox b/doc/C03_TutorialGeometry.dox
index e349c68ce..6d02df40c 100644
--- a/doc/C03_TutorialGeometry.dox
+++ b/doc/C03_TutorialGeometry.dox
@@ -153,7 +153,7 @@ glLoadMatrixf(t.data());\endcode</td></tr>
 <tr><td>
 OpenGL compatibility \b 2D </td><td>\code
 Transform3f aux(Transform3f::Identity);
-aux.linear().corner<2,2>(TopLeft) = t.linear();
+aux.linear().topLeftCorner<2,2>() = t.linear();
 aux.translation().start<2>() = t.translation();
 glLoadMatrixf(aux.data());\endcode</td></tr>
 </table>
diff --git a/doc/Overview.dox b/doc/Overview.dox
index 10463900e..6b7000c4d 100644
--- a/doc/Overview.dox
+++ b/doc/Overview.dox
@@ -11,7 +11,7 @@ o /** \mainpage Eigen
 
 This is the API documentation for Eigen3.
 
-You come from Eigen2? Here is a \ref Eigen2ToEigen3 guide for porting your application from Eigen2 to Eigen3.
+Eigen2 users: here is a \ref Eigen2ToEigen3 guide to help porting your application.
 
 For a first contact with Eigen, the best place is to have a look at the \ref TutorialCore "tutorial". For an even shorter overview, we have an <a href="AsciiQuickReference.txt">ASCII quick reference</a> with Matlab translations.
 
diff --git a/doc/echelon.cpp b/doc/echelon.cpp
deleted file mode 100644
index c95be6f3b..000000000
--- a/doc/echelon.cpp
+++ /dev/null
@@ -1,121 +0,0 @@
-#include <Eigen/Core>
-
-USING_PART_OF_NAMESPACE_EIGEN
-
-namespace Eigen {
-
-/* Echelon a matrix in-place:
- *
- * Meta-Unrolled version, for small fixed-size matrices
- */
-template<typename Derived, int Step>
-struct unroll_echelon
-{
-  enum { k = Step - 1,
-         Rows = Derived::RowsAtCompileTime,
-         Cols = Derived::ColsAtCompileTime,
-         CornerRows = Rows - k,
-         CornerCols = Cols - k
-  };
-  static void run(MatrixBase<Derived>& m)
-  {
-    unroll_echelon<Derived, Step-1>::run(m);
-    int rowOfBiggest, colOfBiggest;
-    m.template corner<CornerRows, CornerCols>(BottomRight)
-     .cwise().abs()
-     .maxCoeff(&rowOfBiggest, &colOfBiggest);
-    m.row(k).swap(m.row(k+rowOfBiggest));
-    m.col(k).swap(m.col(k+colOfBiggest));
-    m.template corner<CornerRows-1, CornerCols>(BottomRight)
-      -= m.col(k).template tail<CornerRows-1>()
-       * (m.row(k).template tail<CornerCols>() / m(k,k));
-  }
-};
-
-template<typename Derived>
-struct unroll_echelon<Derived, 0>
-{
-  static void run(MatrixBase<Derived>& m) {}
-};
-
-/* Echelon a matrix in-place:
- *
- * Non-unrolled version, for dynamic-size matrices.
- * (this version works for all matrices, but in the fixed-size case the other
- * version is faster).
- */
-template<typename Derived>
-struct unroll_echelon<Derived, Dynamic>
-{
-  static void run(MatrixBase<Derived>& m)
-  {
-    for(int k = 0; k < m.diagonal().size() - 1; k++)
-    {
-      int rowOfBiggest, colOfBiggest;
-      int cornerRows = m.rows()-k, cornerCols = m.cols()-k;
-      m.corner(BottomRight, cornerRows, cornerCols)
-      .cwise().abs()
-      .maxCoeff(&rowOfBiggest, &colOfBiggest);
-      m.row(k).swap(m.row(k+rowOfBiggest));
-      m.col(k).swap(m.col(k+colOfBiggest));
-      m.corner(BottomRight, cornerRows-1, cornerCols)
-        -= m.col(k).tail(cornerRows-1) * (m.row(k).tail(cornerCols) / m(k,k));
-    }
-  }
-};
-
-using namespace std;
-template<typename Derived>
-void echelon(MatrixBase<Derived>& m)
-{
-  const int size = DiagonalCoeffs<Derived>::SizeAtCompileTime;
-  const bool unroll = size <= 4;
-  unroll_echelon<Derived, unroll ? size-1 : Dynamic>::run(m);
-}
-
-template<typename Derived>
-void doSomeRankPreservingOperations(MatrixBase<Derived>& m)
-{
-  for(int a = 0; a < 3*(m.rows()+m.cols()); a++)
-  {
-    double d = ei_random<double>(-1,1);
-    int i = ei_random<int>(0,m.rows()-1); // i is a random row number
-    int j;
-    do {
-      j = ei_random<int>(0,m.rows()-1);
-    } while (i==j); // j is another one (must be different)
-    m.row(i) += d * m.row(j);
-
-    i = ei_random<int>(0,m.cols()-1); // i is a random column number
-    do {
-      j = ei_random<int>(0,m.cols()-1);
-    } while (i==j); // j is another one (must be different)
-    m.col(i) += d * m.col(j);
-  }
-}
-
-} // namespace Eigen
-
-using namespace std;
-
-int main(int, char **)
-{
-  srand((unsigned int)time(0));
-  const int Rows = 6, Cols = 4;
-  typedef Matrix<double, Rows, Cols> Mat;
-  const int N = Rows < Cols ? Rows : Cols;
-
-  // start with a matrix m that's obviously of rank N-1
-  Mat m = Mat::identity(Rows, Cols); // args just in case of dyn. size
-  m.row(0) = m.row(1) = m.row(0) + m.row(1);
-
-  doSomeRankPreservingOperations(m);
-
-  // now m is still a matrix of rank N-1
-  cout << "Here's the matrix m:" << endl << m << endl;
-
-  cout << "Now let's echelon m (repeating many times for benchmarking purposes):" << endl;
-  for(int i = 0; i < 1000000; i++) echelon(m);
-
-  cout << "Now m is:" << endl << m << endl;
-}
diff --git a/doc/snippets/MatrixBase_corner_enum_int_int.cpp b/doc/snippets/MatrixBase_corner_enum_int_int.cpp
deleted file mode 100644
index fd6c950cc..000000000
--- a/doc/snippets/MatrixBase_corner_enum_int_int.cpp
+++ /dev/null
@@ -1,6 +0,0 @@
-Matrix4i m = Matrix4i::Random();
-cout << "Here is the matrix m:" << endl << m << endl;
-cout << "Here is the bottom-right 2x3 corner in m:" << endl
-     << m.corner(Eigen::BottomRight, 2, 3) << endl;
-m.corner(Eigen::BottomRight, 2, 3).setZero();
-cout << "Now the matrix m is:" << endl << m << endl;
diff --git a/doc/snippets/MatrixBase_template_int_int_corner_enum.cpp b/doc/snippets/MatrixBase_template_int_int_corner_enum.cpp
deleted file mode 100644
index 05ed0ad2f..000000000
--- a/doc/snippets/MatrixBase_template_int_int_corner_enum.cpp
+++ /dev/null
@@ -1,6 +0,0 @@
-Matrix4i m = Matrix4i::Random();
-cout << "Here is the matrix m:" << endl << m << endl;
-cout << "Here is the bottom-right 2x3 corner in m:" << endl
-     << m.corner<2,3>(Eigen::BottomRight) << endl;
-m.corner<2,3>(Eigen::BottomRight).setZero();
-cout << "Now the matrix m is:" << endl << m << endl;