diff --git a/src/problem.rs b/src/problem.rs
index 7e9856e..0738445 100644
--- a/src/problem.rs
+++ b/src/problem.rs
@@ -1,5 +1,5 @@
 use nalgebra::SVector;
-use roots::find_root_regula_falsi;
+use roots::{find_root_regula_falsi, SimpleConvergency};
 
 use super::callback::Callback;
 use super::controller::{Controller, PIController};
@@ -30,6 +30,7 @@ where
         }
     }
     pub fn solve(&mut self) -> Solution<S, D> {
+        let mut convergency = SimpleConvergency{ eps: 1e-14, max_iter: 150 };
         let mut times: Vec<f64> = vec![self.ode.t];
         let mut states: Vec<SVector<f64, D>> = vec![self.ode.y];
         let mut dense_coefficients: Vec<Vec<SVector<f64, D>>> = Vec::new();
@@ -71,7 +72,7 @@ where
                             let test_y = self.integrator.step(&self.ode, test_t).0;
                             (callback.event)(self.ode.t + test_t, test_y, &self.ode.params)
                         };
-                        let root = find_root_regula_falsi(0.0, step, &f, &mut 1e-8).unwrap();
+                        let root = find_root_regula_falsi(0.0, step, &f, &mut convergency).unwrap();
                         step = root;
                         (new_y, _, dense_option) = self.integrator.step(&self.ode, step);
                         (callback.effect)(&mut self.ode);