diff --git a/core/test/utils/assertions.hpp b/core/test/utils/assertions.hpp
index 174d4536657..87a4e878fc7 100644
--- a/core/test/utils/assertions.hpp
+++ b/core/test/utils/assertions.hpp
@@ -140,7 +140,6 @@ template <typename Ostream, typename MatrixData1, typename MatrixData2>
 void print_componentwise_error(Ostream& os, const MatrixData1& first,
                                const MatrixData2& second)
 {
-    using std::abs;
     using vt = typename detail::biggest_valuetype<
         typename MatrixData1::value_type,
         typename MatrixData2::value_type>::type;
diff --git a/cuda/base/types.hpp b/cuda/base/types.hpp
index c7fe79b5a6f..367674ac163 100644
--- a/cuda/base/types.hpp
+++ b/cuda/base/types.hpp
@@ -100,10 +100,6 @@ __device__ __forceinline__ bool is_nan(const thrust::complex<__half>& val)
 #endif
 
 
-namespace kernels {
-namespace cuda {
-
-
 #ifdef __CUDACC__
 #if defined(__CUDA_ARCH__) && __CUDA_ARCH__ >= 530
 
@@ -138,6 +134,9 @@ __device__ __forceinline__ __half sqrt(const __half& val)
 #endif
 #endif
 
+
+namespace kernels {
+namespace cuda {
 namespace detail {
 
 /**
diff --git a/hip/base/types.hip.hpp b/hip/base/types.hip.hpp
index a52dfe0b239..febead4f370 100644
--- a/hip/base/types.hip.hpp
+++ b/hip/base/types.hip.hpp
@@ -88,35 +88,8 @@ THRUST_HALF_FRIEND_OPERATOR(/, /=)
 
 
 namespace gko {
-#if GINKGO_HIP_PLATFORM_NVCC
-// from the cuda_fp16.hpp
-#if defined(__CUDA_ARCH__) && __CUDA_ARCH__ >= 530
-__device__ __forceinline__ bool is_nan(const __half& val)
-{
-    return __hisnan(val);
-}
 
-#if CUDA_VERSION >= 10020
-__device__ __forceinline__ __half abs(const __half& val) { return __habs(val); }
-#else
-__device__ __forceinline__ __half abs(const __half& val)
-{
-    return abs(static_cast<float>(val));
-}
-#endif
-#else
-__device__ __forceinline__ bool is_nan(const __half& val)
-{
-    return is_nan(static_cast<float>(val));
-}
 
-__device__ __forceinline__ __half abs(const __half& val)
-{
-    return abs(static_cast<float>(val));
-}
-#endif
-
-#else  // Not nvidia device
 __device__ __forceinline__ bool is_nan(const __half& val)
 {
     return __hisnan(val);
@@ -125,8 +98,6 @@ __device__ __forceinline__ bool is_nan(const __half& val)
 // rocm40 __habs is not constexpr
 __device__ __forceinline__ __half abs(const __half& val) { return __habs(val); }
 
-#endif
-
 
 namespace kernels {
 namespace hip {
diff --git a/include/ginkgo/core/base/math.hpp b/include/ginkgo/core/base/math.hpp
index fb73c9c3cd6..79802a08350 100644
--- a/include/ginkgo/core/base/math.hpp
+++ b/include/ginkgo/core/base/math.hpp
@@ -35,106 +35,6 @@ class complex;
 namespace gko {
 
 
-using std::abs;
-using std::sqrt;
-
-GKO_INLINE gko::half abs(gko::half a) { return gko::half((a > 0) ? a : -a); }
-
-GKO_INLINE gko::half abs(std::complex<gko::half> a)
-{
-    // Using float abs not sqrt on norm to avoid overflow
-    return gko::half(abs(std::complex<float>(a)));
-}
-
-
-GKO_INLINE gko::half sqrt(gko::half a)
-{
-    return gko::half(std::sqrt(float(a)));
-}
-
-GKO_INLINE std::complex<gko::half> sqrt(std::complex<gko::half> a)
-{
-    return std::complex<gko::half>(sqrt(std::complex<float>(
-        static_cast<float>(a.real()), static_cast<float>(a.imag()))));
-}
-
-
-}  // namespace gko
-
-
-namespace gko {
-
-
-// HIP should not see std::abs or std::sqrt, we want the custom implementation.
-// Hence, provide the using declaration only for some cases
-namespace kernels {
-namespace reference {
-
-
-using std::abs;
-
-
-using std::sqrt;
-
-
-}  // namespace reference
-}  // namespace kernels
-
-
-namespace kernels {
-namespace omp {
-
-
-using std::abs;
-
-
-using std::sqrt;
-
-
-}  // namespace omp
-}  // namespace kernels
-
-
-namespace kernels {
-namespace cuda {
-
-
-using std::abs;
-
-
-using std::sqrt;
-
-
-}  // namespace cuda
-}  // namespace kernels
-
-
-namespace kernels {
-namespace dpcpp {
-
-
-using std::abs;
-
-
-using std::sqrt;
-
-
-}  // namespace dpcpp
-}  // namespace kernels
-
-
-namespace test {
-
-
-using std::abs;
-
-
-using std::sqrt;
-
-
-}  // namespace test
-
-
 // type manipulations
 
 
@@ -1030,6 +930,7 @@ GKO_INLINE constexpr auto squared_norm(const T& x)
     return real(conj(x) * x);
 }
 
+using std::abs;
 
 /**
  * Returns the absolute value of the object.
@@ -1055,6 +956,27 @@ abs(const T& x)
     return sqrt(squared_norm(x));
 }
 
+// increase the priority in function lookup
+GKO_INLINE gko::half abs(const std::complex<gko::half>& x)
+{
+    // Using float abs not sqrt on norm to avoid overflow
+    return static_cast<gko::half>(abs(std::complex<float>(x)));
+}
+
+
+using std::sqrt;
+
+GKO_INLINE gko::half sqrt(gko::half a)
+{
+    return gko::half(std::sqrt(float(a)));
+}
+
+GKO_INLINE std::complex<gko::half> sqrt(std::complex<gko::half> a)
+{
+    return std::complex<gko::half>(sqrt(std::complex<float>(
+        static_cast<float>(a.real()), static_cast<float>(a.imag()))));
+}
+
 
 /**
  * Returns the value of pi.