diff --git a/sbp/src/operators/interpolation.rs b/sbp/src/operators/interpolation.rs
index c69d834..0b70f3b 100644
--- a/sbp/src/operators/interpolation.rs
+++ b/sbp/src/operators/interpolation.rs
@@ -54,21 +54,21 @@ pub(crate) fn test_interpolation_operator<IO: InterpolationOperator>(op: IO, h2:
     let nc = 101;
     let (x_c, x_f) = if h2 {
         (
-            crate::utils::h2linspace(0.0, 1.0, nc),
-            crate::utils::h2linspace(0.0, 1.0, 2 * (nc - 1)),
+            crate::utils::h2linspace(20.0, 50.0, nc),
+            crate::utils::h2linspace(20.0, 50.0, 2 * (nc - 1)),
         )
     } else {
         (
-            ndarray::Array1::linspace(0.0, 1.0, 101),
-            ndarray::Array1::linspace(0.0, 1.0, 2 * nc - 1),
+            ndarray::Array1::linspace(20.0, 50.0, 101),
+            ndarray::Array1::linspace(20.0, 50.0, 2 * nc - 1),
         )
     };
 
     let mut ix_f = ndarray::Array1::zeros(x_f.raw_dim());
     op.coarse2fine(x_c.view(), ix_f.view_mut());
-    approx::assert_abs_diff_eq!(ix_f, x_f, epsilon = 1e-5);
+    approx::assert_abs_diff_eq!(ix_f, x_f, epsilon = 1e-11);
 
     let mut ix_c = ndarray::Array1::zeros(x_c.raw_dim());
     op.fine2coarse(x_f.view(), ix_c.view_mut());
-    approx::assert_abs_diff_eq!(ix_c, x_c, epsilon = 1e-5);
+    approx::assert_abs_diff_eq!(ix_c, x_c, epsilon = 1e-11);
 }