Use also epsilon as an absolute error

src/algebra/LinearSolver.cpp

@@ -186,7 +186,7 @@ struct LinearSolver::Internals
 
     KSP ksp;
     KSPCreate(PETSC_COMM_SELF, &ksp);
-    KSPSetTolerances(ksp, options.epsilon(), 1E-100, 1E5, options.maximumIteration());
+    KSPSetTolerances(ksp, options.epsilon(), options.epsilon(), 1E5, options.maximumIteration());
 
     KSPSetOperators(ksp, petscA, petscA);