1. Remove constant_sparsity from LinearSolver::Options. It introduces
unnecessarily complexity in the structure of linear solvers and preconditioners.
This is the first step towards cleaning up the Preconditioner interface.
2. Minor tweaks and cleanups to the various linear solvers.
diff --git a/internal/ceres/detect_structure.h b/internal/ceres/detect_structure.h
index 8af4f23..5f8e1b4 100644
--- a/internal/ceres/detect_structure.h
+++ b/internal/ceres/detect_structure.h
@@ -49,7 +49,7 @@
// is known as compile time.
//
// For more details about e_blocks and f_blocks, see
-// schur_complement.h. This information is used to initialized an
+// schur_eliminator.h. This information is used to initialized an
// appropriate template specialization of SchurEliminator.
void DetectStructure(const CompressedRowBlockStructure& bs,
const int num_eliminate_blocks,
