Fix crash in IncompleteCholesky when the input has zeros on the diagonal.
diff --git a/Eigen/src/IterativeLinearSolvers/IncompleteCholesky.h b/Eigen/src/IterativeLinearSolvers/IncompleteCholesky.h
index 14ae6ea..f456c96 100644
--- a/Eigen/src/IterativeLinearSolvers/IncompleteCholesky.h
+++ b/Eigen/src/IterativeLinearSolvers/IncompleteCholesky.h
@@ -214,6 +214,19 @@
m_L.template selfadjointView<Lower>() = mat.template selfadjointView<UpLo_>();
}
+ // The algorithm will insert increasingly large shifts on the diagonal until
+ // factorization succeeds. Therefore we have to make sure that there is a
+ // space in the datastructure to store such values, even if the original
+ // matrix has a zero on the diagonal.
+ bool modified = false;
+ for (Index i = 0; i < mat.cols(); ++i) {
+ if (numext::is_exactly_zero(m_L.coeff(i, i))) {
+ m_L.insert(i, i) = Scalar(0);
+ modified = true;
+ }
+ }
+ if (modified) m_L.makeCompressed();
+
Index n = m_L.cols();
Index nnz = m_L.nonZeros();
Map<VectorSx> vals(m_L.valuePtr(), nnz); // values
