From 2136cfa17e2894376bd5ab2e0393f86734a6f955 Mon Sep 17 00:00:00 2001
From: Jeff Trull <edaskel@att.net>
Date: Thu, 15 Feb 2018 15:00:31 -0800
Subject: [PATCH] Make sparse QR result sizes consistent with dense QR, with
 the following rules:

1) Q is always square
2) Q*R*P' is valid and recovers the original matrix

This implies that the size of Q is the number of rows in the original matrix, square,
and that the size of R is the size of the original matrix.
---
 Eigen/src/SparseQR/SparseQR.h | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/Eigen/src/SparseQR/SparseQR.h b/Eigen/src/SparseQR/SparseQR.h
index 885622540..7409fcae9 100644
--- a/Eigen/src/SparseQR/SparseQR.h
+++ b/Eigen/src/SparseQR/SparseQR.h
@@ -605,7 +605,7 @@ struct SparseQR_QProduct : ReturnByValue<SparseQR_QProduct<SparseQRType, Derived
   // Get the references 
   SparseQR_QProduct(const SparseQRType& qr, const Derived& other, bool transpose) : 
   m_qr(qr),m_other(other),m_transpose(transpose) {}
-  inline Index rows() const { return m_transpose ? m_qr.rows() : m_qr.cols(); }
+  inline Index rows() const { return m_qr.matrixQ().rows(); }
   inline Index cols() const { return m_other.cols(); }
   
   // Assign to a vector
@@ -633,7 +633,10 @@ struct SparseQR_QProduct : ReturnByValue<SparseQR_QProduct<SparseQRType, Derived
     }
     else
     {
-      eigen_assert(m_qr.m_Q.rows() == m_other.rows() && "Non conforming object sizes");
+      eigen_assert(m_qr.matrixQ().cols() == m_other.rows() && "Non conforming object sizes");
+
+      res.conservativeResize(rows(), cols());
+
       // Compute res = Q * other column by column
       for(Index j = 0; j < res.cols(); j++)
       {
@@ -675,7 +678,7 @@ struct SparseQRMatrixQReturnType : public EigenBase<SparseQRMatrixQReturnType<Sp
     return SparseQRMatrixQTransposeReturnType<SparseQRType>(m_qr);
   }
   inline Index rows() const { return m_qr.rows(); }
-  inline Index cols() const { return (std::min)(m_qr.rows(),m_qr.cols()); }
+  inline Index cols() const { return m_qr.rows(); }
   // To use for operations with the transpose of Q FIXME this is the same as adjoint at the moment
   SparseQRMatrixQTransposeReturnType<SparseQRType> transpose() const
   {
@@ -715,7 +718,7 @@ struct Assignment<DstXprType, SparseQRMatrixQReturnType<SparseQRType>, internal:
   typedef typename DstXprType::StorageIndex StorageIndex;
   static void run(DstXprType &dst, const SrcXprType &src, const internal::assign_op<Scalar,Scalar> &/*func*/)
   {
-    typename DstXprType::PlainObject idMat(src.m_qr.rows(), src.m_qr.rows());
+    typename DstXprType::PlainObject idMat(src.rows(), src.cols());
     idMat.setIdentity();
     // Sort the sparse householder reflectors if needed
     const_cast<SparseQRType *>(&src.m_qr)->_sort_matrix_Q();