1 files changed, 12 insertions, 17 deletions
diff --git a/Eigen/src/LU/PartialPivLU.h b/Eigen/src/LU/PartialPivLU.h
index 37cffd7a1..deb29b5c6 100644
--- a/Eigen/src/LU/PartialPivLU.h
+++ b/Eigen/src/LU/PartialPivLU.h
@@ -64,10 +64,8 @@ template<typename _MatrixType> class PartialPivLU
     typedef _MatrixType MatrixType;
     typedef typename MatrixType::Scalar Scalar;
     typedef typename NumTraits<typename MatrixType::Scalar>::Real RealScalar;
-    typedef Matrix<int, 1, MatrixType::ColsAtCompileTime> IntRowVectorType;
-    typedef Matrix<int, MatrixType::RowsAtCompileTime, 1> IntColVectorType;
-    typedef Matrix<Scalar, 1, MatrixType::ColsAtCompileTime> RowVectorType;
-    typedef Matrix<Scalar, MatrixType::RowsAtCompileTime, 1> ColVectorType;
+    typedef Matrix<int, MatrixType::RowsAtCompileTime, 1> PermutationVectorType;
+    typedef PermutationMatrix<MatrixType::RowsAtCompileTime> PermutationType;
 
     enum { MaxSmallDimAtCompileTime = EIGEN_ENUM_MIN(
              MatrixType::MaxColsAtCompileTime,
@@ -105,11 +103,9 @@ template<typename _MatrixType> class PartialPivLU
       return m_lu;
     }
 
-    /** \returns a vector of integers, whose size is the number of rows of the matrix being decomposed,
-      * representing the P permutation i.e. the permutation of the rows. For its precise meaning,
-      * see the examples given in the documentation of class FullPivLU.
+    /** \returns the permutation matrix P.
       */
-    inline const IntColVectorType& permutationP() const
+    inline const PermutationType& permutationP() const
     {
       ei_assert(m_isInitialized && "PartialPivLU is not initialized.");
       return m_p;
@@ -147,11 +143,11 @@ template<typename _MatrixType> class PartialPivLU
       *
       * \sa MatrixBase::inverse(), LU::inverse()
       */
-    inline const ei_solve_retval<PartialPivLU,NestByValue<typename MatrixType::IdentityReturnType> > inverse() const
+    inline const ei_solve_retval<PartialPivLU,typename MatrixType::IdentityReturnType> inverse() const
     {
       ei_assert(m_isInitialized && "PartialPivLU is not initialized.");
-      return ei_solve_retval<PartialPivLU,NestByValue<typename MatrixType::IdentityReturnType> >
-               (*this, MatrixType::Identity(m_lu.rows(), m_lu.cols()).nestByValue());
+      return ei_solve_retval<PartialPivLU,typename MatrixType::IdentityReturnType>
+               (*this, MatrixType::Identity(m_lu.rows(), m_lu.cols()));
     }
 
     /** \returns the determinant of the matrix of which
@@ -174,7 +170,7 @@ template<typename _MatrixType> class PartialPivLU
 
   protected:
     MatrixType m_lu;
-    IntColVectorType m_p;
+    PermutationType m_p;
     int m_det_p;
     bool m_isInitialized;
 };
@@ -379,20 +375,19 @@ template<typename MatrixType>
 PartialPivLU<MatrixType>& PartialPivLU<MatrixType>::compute(const MatrixType& matrix)
 {
   m_lu = matrix;
-  m_p.resize(matrix.rows());
 
   ei_assert(matrix.rows() == matrix.cols() && "PartialPivLU is only for square (and moreover invertible) matrices");
   const int size = matrix.rows();
 
-  IntColVectorType rows_transpositions(size);
+  PermutationVectorType rows_transpositions(size);
 
   int nb_transpositions;
   ei_partial_lu_inplace(m_lu, rows_transpositions, nb_transpositions);
   m_det_p = (nb_transpositions%2) ? -1 : 1;
 
-  for(int k = 0; k < size; ++k) m_p.coeffRef(k) = k;
+  m_p.setIdentity(size);
   for(int k = size-1; k >= 0; --k)
-    std::swap(m_p.coeffRef(k), m_p.coeffRef(rows_transpositions.coeff(k)));
+    m_p.applyTranspositionOnTheRight(k, rows_transpositions.coeff(k));
 
   m_isInitialized = true;
   return *this;
@@ -428,7 +423,7 @@ struct ei_solve_retval<PartialPivLU<_MatrixType>, Rhs>
     dst.resize(size, rhs().cols());
 
     // Step 1
-    for(int i = 0; i < size; ++i) dst.row(dec().permutationP().coeff(i)) = rhs().row(i);
+    dst = dec().permutationP() * rhs();
 
     // Step 2
     dec().matrixLU().template triangularView<UnitLowerTriangular>().solveInPlace(dst);