- introduce Part and Extract classes, splitting and extending the former

Triangular class
- full meta-unrolling in Part
- move inverseProduct() to MatrixBase
- compilation fix in ProductWIP: introduce a meta-selector to only do
  direct access on types that support it.
- phase out the old Product, remove the WIP_DIRTY stuff.
- misc renaming and fixes

Eigen/src/Cholesky/Cholesky.h

@@ -58,9 +58,9 @@ template<typename MatrixType> class Cholesky
       compute(matrix);
     }
 
-    Triangular<Lower, MatrixType> matrixL(void) const
+    Extract<MatrixType, Lower> matrixL(void) const
     {
-      return m_matrix.lower();
+      return m_matrix;
     }
 
     bool isPositiveDefinite(void) const { return m_isPositiveDefinite; }
@@ -118,7 +118,7 @@ typename Derived::Eval Cholesky<MatrixType>::solve(MatrixBase<Derived> &b)
   const int size = m_matrix.rows();
   ei_assert(size==b.size());
 
-  return m_matrix.adjoint().upper().inverseProduct(m_matrix.lower().inverseProduct(b));
+  return m_matrix.adjoint().template extract<Upper>().inverseProduct(matrixL().inverseProduct(b));
 }
 
 

Eigen/src/Cholesky/CholeskyWithoutSquareRoot.h

@@ -58,9 +58,9 @@ template<typename MatrixType> class CholeskyWithoutSquareRoot
     }
 
     /** \returns the lower triangular matrix L */
-    Triangular<Lower|UnitDiagBit, MatrixType > matrixL(void) const
+    Extract<MatrixType, UnitLower> matrixL(void) const
     {
-      return m_matrix.lowerWithUnitDiag();
+      return m_matrix;
     }
 
     /** \returns the coefficients of the diagonal matrix D */
@@ -131,9 +131,9 @@ typename Derived::Eval CholeskyWithoutSquareRoot<MatrixType>::solve(MatrixBase<D
   const int size = m_matrix.rows();
   ei_assert(size==vecB.size());
 
-  return m_matrix.adjoint().upperWithUnitDiag()
+  return m_matrix.adjoint().template extract<UnitUpper>()
     .inverseProduct(
-      (m_matrix.lowerWithUnitDiag()
+      (matrixL()
         .inverseProduct(vecB))
         .cwiseQuotient(m_matrix.diagonal())
       );