I want to compute the determinant of a sparse matrix using SparseLU and absDeterminant(), signDeterminant(). However, I get incorrect results:

Code: Select all

#include <iostream>
#include <Eigen/Dense>
#include <Eigen/Sparse>

using namespace std;
using namespace Eigen;

int main() {
   MatrixXd m(2,2);
   m << 2,1,1,1;
   cout << "det=" << m.determinant() << endl;
   SparseMatrix<double> sm = m.sparseView();
   SparseLU<SparseMatrix<double> > slu;
   slu.compute(sm);
   cout << "det=" << slu.absDeterminant() << endl;
}


Did I miss something?

The documentation of absDeterminant and logAbsDeterminant mentions QR decomposition. I think the LU decomposition is meant. Also logAbsDeterminant refers to **this which should be *this.

Our mistake, fixed in 3.2 and devel branches.
https://bitbucket.org/eigen/eigen/commits/0e64f7b3e7d7/
https://bitbucket.org/eigen/eigen/commits/cd870bd62527/

Thanks!