diff --git a/MathLib/LinAlg/LinearSolverOptions.cpp b/MathLib/LinAlg/LinearSolverOptions.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..6c42a036dfad1d211b7daca4c7fb655e8f793847
--- /dev/null
+++ b/MathLib/LinAlg/LinearSolverOptions.cpp
@@ -0,0 +1,25 @@
+#include "LinearSolverOptions.h"
+
+#include <set>
+
+//! Configuration tag names of all known linear solvers for their
+//! configuration in the project file.
+//! Add your tag name here when you add a new solver.
+static
+std::set<std::string>
+known_linear_solvers { "eigen", "lis", "petsc" };
+
+namespace MathLib
+{
+
+
+void
+ignoreOtherLinearSolvers(const BaseLib::ConfigTreeNew &config,
+                         const std::string &solver_name)
+{
+    for (auto const& s : known_linear_solvers) {
+        if (s!=solver_name) config.ignoreConfParam(s);
+    }
+}
+
+}
diff --git a/MathLib/LinAlg/LinearSolverOptions.h b/MathLib/LinAlg/LinearSolverOptions.h
new file mode 100644
index 0000000000000000000000000000000000000000..8a36efd814e7c5fc81d1990256eb4740615ded4e
--- /dev/null
+++ b/MathLib/LinAlg/LinearSolverOptions.h
@@ -0,0 +1,29 @@
+#pragma once
+
+#include "BaseLib/ConfigTreeNew.h"
+
+namespace MathLib
+{
+
+/*! Ignore linear solver settings not needed for the selected one.
+ *
+ * The project files support specifying linear solver options for all
+ * known solver libraries (currently PETSC, LIS, Eigen) even though for
+ * a specific build only one of those settings is used.
+ * That clearly conflicts with the requirement of the config tree that
+ * each setting present in the project file must be read exactly once.
+ *
+ * The purpose of this function is to explicitly ignore all the settings
+ * that are not relevant for the currently used linear solver
+ *
+ * \param config The config tree snippet for the linear solver.
+ * \param solver_name The tag under which the relevant configuration is found.
+ *                    All other configurations will be ignored.
+ *
+ * This function is currently used in the option parsing code of our
+ * \c EigenLinearSolver, \c LisOption and \c PETScLinearSolver
+ */
+void ignoreOtherLinearSolvers(BaseLib::ConfigTreeNew const& config,
+                              std::string const& solver_name);
+
+}