diff --git a/examples/benchmark.rs b/examples/benchmark.rs
index a8f802d..d3c2408 100644
--- a/examples/benchmark.rs
+++ b/examples/benchmark.rs
@@ -1,11 +1,15 @@
 use phastft::fft_dif;
+use phastft::utils::gen_random_signal;
 
 fn bm_fft(num_qubits: usize) {
     for i in 4..num_qubits {
         println!("run PhastFT with {i} qubits");
         let n = 1 << i;
-        let mut reals: Vec<f64> = (1..=n).map(f64::from).collect();
-        let mut imags: Vec<f64> = (1..=n).map(f64::from).collect();
+
+        let mut reals = vec![0.0; n];
+        let mut imags = vec![0.0; n];
+
+        gen_random_signal(&mut reals, &mut imags);
 
         let now = std::time::Instant::now();
         fft_dif(&mut reals, &mut imags);
diff --git a/src/twiddles.rs b/src/twiddles.rs
index 58f33d5..de5f2a2 100644
--- a/src/twiddles.rs
+++ b/src/twiddles.rs
@@ -135,8 +135,8 @@ pub(crate) fn generate_twiddles_simd(dist: usize) -> (Vec<f64>, Vec<f64>) {
                 // This avoids data dependencies of the regular calculation and gets vectorized.
                 // We do it up front while the values we just calculated are still in the cache
                 // so we don't have to re-load them from memory later, which would be slow.
-                apply_symmetry_re(&first_ch_re, second_ch_re);
-                apply_symmetry_im(&first_ch_im, second_ch_im);
+                apply_symmetry_re(first_ch_re, second_ch_re);
+                apply_symmetry_im(first_ch_im, second_ch_im);
             },
         );
 
diff --git a/src/utils.rs b/src/utils.rs
index 7264eae..d7a9d56 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -6,7 +6,7 @@ use std::f64::consts::PI;
 #[allow(dead_code)]
 #[track_caller]
 pub(crate) fn assert_f64_closeness(actual: f64, expected: f64, epsilon: f64) {
-    if !((actual - expected).abs() < epsilon) {
+    if (actual - expected).abs() >= epsilon {
         panic!(
             "Assertion failed: {} too far from expected value {} (with epsilon {})",
             actual, expected, epsilon
@@ -18,7 +18,7 @@ pub(crate) fn assert_f64_closeness(actual: f64, expected: f64, epsilon: f64) {
 #[allow(dead_code)]
 #[track_caller]
 pub(crate) fn assert_f32_closeness(actual: f32, expected: f32, epsilon: f32) {
-    if !((actual - expected).abs() < epsilon) {
+    if (actual - expected).abs() >= epsilon {
         panic!(
             "Assertion failed: {} too far from expected value {} (with epsilon {})",
             actual, expected, epsilon
@@ -27,7 +27,7 @@ pub(crate) fn assert_f32_closeness(actual: f32, expected: f32, epsilon: f32) {
 }
 
 pub fn gen_random_signal(reals: &mut [f64], imags: &mut [f64]) {
-    assert!(reals.len() == imags.len() && reals.len() > 0);
+    assert!(reals.len() == imags.len() && !reals.is_empty());
     let mut rng = thread_rng();
     let between = Uniform::from(0.0..1.0);
     let angle_dist = Uniform::from(0.0..2.0 * PI);