diff --git a/benchmarks/benchmark_utils.hpp b/benchmarks/benchmark_utils.hpp
index 617ad6c..228b88e 100644
--- a/benchmarks/benchmark_utils.hpp
+++ b/benchmarks/benchmark_utils.hpp
@@ -7,17 +7,17 @@
 
 #include <benchmark/benchmark.h>
 
-// Default values if not overridden by range multipliers
-constexpr size_t DEFAULT_N = 10'000'000;
+void init_x(std::vector<float> &x) {
+  for (size_t i = 0; i < x.size(); ++i) {
+    x[i] = (i % 360) * 0.0174533f; // degrees to radians
+  }
+}
 
 template <typename Backend>
 static void benchmark_sinf(benchmark::State &state) {
   const size_t N = static_cast<size_t>(state.range(0));
   std::vector<float> x(N), s(N);
-
-  for (size_t i = 0; i < N; ++i) {
-    x[i] = (i % 360) * 0.0174533f; // degrees to radians
-  }
+  init_x(x);
 
   Backend backend;
 
@@ -42,10 +42,7 @@ template <typename Backend>
 static void benchmark_cosf(benchmark::State &state) {
   const size_t N = static_cast<size_t>(state.range(0));
   std::vector<float> x(N), c(N);
-
-  for (size_t i = 0; i < N; ++i) {
-    x[i] = (i % 360) * 0.0174533f;
-  }
+  init_x(x);
 
   Backend backend;
 
@@ -70,10 +67,7 @@ template <typename Backend>
 static void benchmark_sincosf(benchmark::State &state) {
   const size_t N = static_cast<size_t>(state.range(0));
   std::vector<float> x(N), s(N), c(N);
-
-  for (size_t i = 0; i < N; ++i) {
-    x[i] = (i % 360) * 0.0174533f;
-  }
+  init_x(x);
 
   Backend backend;
 
diff --git a/src/gpu.cpp b/src/gpu.cpp
index 38ef92b..b6be96f 100644
--- a/src/gpu.cpp
+++ b/src/gpu.cpp
@@ -45,25 +45,29 @@ struct GPUBackend::Impl {
     const size_t bytes = n * sizeof(float);
     std::memcpy(h_x, x, bytes);
     cudaMemcpy(d_x, h_x, bytes, cudaMemcpyHostToDevice);
-    launch_sincosf_kernel(d_x, d_s, d_c, n);
+    launch_sinf_kernel(d_x, d_s, n);
     cudaMemcpy(h_s, d_s, bytes, cudaMemcpyDeviceToHost);
     std::memcpy(s, h_s, bytes);
   }
 
   void compute_cosf(size_t n, const float *x, float *c) const {
     const size_t bytes = n * sizeof(float);
+    std::memcpy(h_x, x, bytes);
     cudaMemcpy(d_x, h_x, bytes, cudaMemcpyHostToDevice);
-    launch_sincosf_kernel(d_x, d_s, d_c, n);
+    launch_cosf_kernel(d_x, d_c, n);
     cudaMemcpy(h_c, d_c, bytes, cudaMemcpyDeviceToHost);
     std::memcpy(c, h_c, bytes);
   }
 
   void compute_sincosf(size_t n, const float *x, float *s, float *c) const {
     const size_t bytes = n * sizeof(float);
+    std::memcpy(h_x, x, bytes);
     cudaMemcpy(d_x, h_x, bytes, cudaMemcpyHostToDevice);
     launch_sincosf_kernel(d_x, d_s, d_c, n);
     cudaMemcpy(h_s, d_s, bytes, cudaMemcpyDeviceToHost);
     cudaMemcpy(h_c, d_c, bytes, cudaMemcpyDeviceToHost);
+    std::memcpy(s, h_s, bytes);
+    std::memcpy(c, h_c, bytes);
   }
 
   float *h_x = nullptr;
diff --git a/tests/test_gpu.cpp b/tests/test_gpu.cpp
index 6e06419..2fbd28f 100644
--- a/tests/test_gpu.cpp
+++ b/tests/test_gpu.cpp
@@ -3,8 +3,8 @@
 
 #include "test_utils.hpp"
 
-TEST_CASE("sinf") { test_sinf<GPUBackend>(1e-1f); }
+TEST_CASE("sinf") { test_sinf<GPUBackend>(1e-6f); }
 
-TEST_CASE("cosf") { test_cosf<GPUBackend>(1e-1f); }
+TEST_CASE("cosf") { test_cosf<GPUBackend>(1e-6f); }
 
-TEST_CASE("sincosf") { test_sincosf<GPUBackend>(1e-1f); }
+TEST_CASE("sincosf") { test_sincosf<GPUBackend>(1e-6f); }
diff --git a/tests/test_utils.hpp b/tests/test_utils.hpp
index e366bef..4447d65 100644
--- a/tests/test_utils.hpp
+++ b/tests/test_utils.hpp
@@ -9,12 +9,15 @@
 
 const size_t N = 1e7;
 
+void init_x(std::vector<float> &x) {
+  for (size_t i = 0; i < x.size(); ++i) {
+    x[i] = (i % 360) * 0.0174533f; // degrees to radians
+  }
+}
+
 template <typename Backend> inline void test_sinf(float tol) {
   std::vector<float> x(N), s_ref(N), s(N);
-
-  for (size_t i = 0; i < N; ++i) {
-    x[i] = float(i) * 0.01f;
-  }
+  init_x(x);
 
   ReferenceBackend ref;
   Backend backend;
@@ -30,10 +33,7 @@ template <typename Backend> inline void test_sinf(float tol) {
 
 template <typename Backend> inline void test_cosf(float tol) {
   std::vector<float> x(N), c_ref(N), c(N);
-
-  for (size_t i = 0; i < N; ++i) {
-    x[i] = float(i) * 0.01f;
-  }
+  init_x(x);
 
   ReferenceBackend ref;
   Backend backend;
@@ -49,10 +49,7 @@ template <typename Backend> inline void test_cosf(float tol) {
 
 template <typename Backend> inline void test_sincosf(float tol) {
   std::vector<float> x(N), s_ref(N), c_ref(N), s(N), c(N);
-
-  for (size_t i = 0; i < N; ++i) {
-    x[i] = float(i) * 0.01f;
-  }
+  init_x(x);
 
   ReferenceBackend ref;
   Backend backend;