Hello,

I'm trying to use SparseQR solver to get the rank of the matrix in question. However, it always crashes for my case with more rows than colums. Here a little test that crashes for rows>cols but works for cols>rows and square case:

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Eigen::SparseMatrix<double> A(4,5);
A.reserve(2);
typedef Eigen::Triplet<double> T;
std::vector<T> tripletList;
tripletList.push_back(T(1,2,1));
tripletList.push_back(T(3,4,2));

A.setFromTriplets(tripletList.begin(), tripletList.end());
std::cout<<A<<std::endl;
Eigen::SparseQR<Eigen::SparseMatrix<double>, Eigen::COLAMDOrdering<int> > solver;
solver.compute(A);


crash report:

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test: /usr/include/eigen3/Eigen/src/Core/Block.h:141: Eigen::Block<XprType, BlockRows, BlockCols, InnerPanel>::Block(XprType&, Eigen::Block<XprType, BlockRows, BlockCols, InnerPanel>::Index, Eigen::Block<XprType, BlockRows, BlockCols, InnerPanel>::Index, Eigen::Block<XprType, BlockRows, BlockCols, InnerPanel>::Index, Eigen::Block<XprType, BlockRows, BlockCols, InnerPanel>::Index) [with XprType = Eigen::Matrix<int, -1, 1>; int BlockRows = -1; int BlockCols = 1; bool InnerPanel = false; Eigen::Block<XprType, BlockRows, BlockCols, InnerPanel>::Index = long int]: Assertion `a_startRow >= 0 && blockRows >= 0 && a_startRow <= xpr.rows() - blockRows && a_startCol >= 0 && blockCols >= 0 && a_startCol <= xpr.cols() - blockCols' failed.


Is this a error on my side, a limitation or a bug? I'm using latest stable Eigen3.2.

EDIT: I just dedected that it works flawless in release compilation, the crash is only triggerd in debug (of course, it's a assertion). The rank gets computed correctly. Maybe an unnecessary test?

Regards,
Stefan

this should be fixed in the devel and 3.2 branch