diff --git a/src/avx2-32bit-half.hpp b/src/avx2-32bit-half.hpp
index 3646979..9a72f0d 100644
--- a/src/avx2-32bit-half.hpp
+++ b/src/avx2-32bit-half.hpp
@@ -84,7 +84,7 @@ struct avx2_half_vector<int32_t> {
         return _mm_mask_i32gather_epi32(
                 src, (const int *)base, index, mask, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[3]], arr[ind[2]], arr[ind[1]], arr[ind[0]]);
     }
@@ -237,7 +237,7 @@ struct avx2_half_vector<uint32_t> {
         return _mm_mask_i32gather_epi32(
                 src, (const int *)base, index, mask, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[3]], arr[ind[2]], arr[ind[1]], arr[ind[0]]);
     }
@@ -421,7 +421,7 @@ struct avx2_half_vector<float> {
         return _mm_mask_i32gather_ps(
                 src, (const float *)base, index, _mm_castsi128_ps(mask), scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[3]], arr[ind[2]], arr[ind[1]], arr[ind[0]]);
     }
diff --git a/src/avx2-64bit-qsort.hpp b/src/avx2-64bit-qsort.hpp
index 2af97d6..78bea58 100644
--- a/src/avx2-64bit-qsort.hpp
+++ b/src/avx2-64bit-qsort.hpp
@@ -99,7 +99,7 @@ struct avx2_vector<int64_t> {
         return _mm256_mask_i32gather_epi64(
                 src, (const long long int *)base, index, mask, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[3]], arr[ind[2]], arr[ind[1]], arr[ind[0]]);
     }
@@ -269,7 +269,7 @@ struct avx2_vector<uint64_t> {
         return _mm256_mask_i32gather_epi64(
                 src, (const long long int *)base, index, mask, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[3]], arr[ind[2]], arr[ind[1]], arr[ind[0]]);
     }
@@ -499,7 +499,7 @@ struct avx2_vector<double> {
                                         scale);
         ;
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[3]], arr[ind[2]], arr[ind[1]], arr[ind[0]]);
     }
diff --git a/src/avx512-64bit-common.h b/src/avx512-64bit-common.h
index f27a31f..71599e8 100644
--- a/src/avx512-64bit-common.h
+++ b/src/avx512-64bit-common.h
@@ -99,7 +99,7 @@ struct ymm_vector<float> {
     {
         return _mm256_mmask_i32gather_ps(src, mask, index, base, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[7]],
                    arr[ind[6]],
@@ -293,7 +293,7 @@ struct ymm_vector<uint32_t> {
     {
         return _mm256_mmask_i32gather_epi32(src, mask, index, base, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[7]],
                    arr[ind[6]],
@@ -481,7 +481,7 @@ struct ymm_vector<int32_t> {
     {
         return _mm256_mmask_i32gather_epi32(src, mask, index, base, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[7]],
                    arr[ind[6]],
@@ -680,7 +680,7 @@ struct zmm_vector<int64_t> {
     {
         return _mm512_mask_i32gather_epi64(src, mask, index, base, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[7]],
                    arr[ind[6]],
@@ -843,7 +843,7 @@ struct zmm_vector<uint64_t> {
     {
         return _mm512_mask_i32gather_epi64(src, mask, index, base, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[7]],
                    arr[ind[6]],
@@ -1062,7 +1062,7 @@ struct zmm_vector<double> {
     {
         return _mm512_mask_i32gather_pd(src, mask, index, base, scale);
     }
-    static reg_t i64gather(type_t *arr, arrsize_t *ind)
+    static reg_t i64gather(const type_t *arr, arrsize_t *ind)
     {
         return set(arr[ind[7]],
                    arr[ind[6]],
diff --git a/src/xss-common-argsort.h b/src/xss-common-argsort.h
index 3e80083..1bec821 100644
--- a/src/xss-common-argsort.h
+++ b/src/xss-common-argsort.h
@@ -11,8 +11,11 @@
 #include <numeric>
 
 template <typename T>
-X86_SIMD_SORT_INLINE void std_argselect_withnan(
-        T *arr, arrsize_t *arg, arrsize_t k, arrsize_t left, arrsize_t right)
+X86_SIMD_SORT_INLINE void std_argselect_withnan(const T *arr,
+                                                arrsize_t *arg,
+                                                arrsize_t k,
+                                                arrsize_t left,
+                                                arrsize_t right)
 {
     std::nth_element(arg + left,
                      arg + k,
@@ -32,8 +35,10 @@ X86_SIMD_SORT_INLINE void std_argselect_withnan(
 
 /* argsort using std::sort */
 template <typename T>
-X86_SIMD_SORT_INLINE void
-std_argsort_withnan(T *arr, arrsize_t *arg, arrsize_t left, arrsize_t right)
+X86_SIMD_SORT_INLINE void std_argsort_withnan(const T *arr,
+                                              arrsize_t *arg,
+                                              arrsize_t left,
+                                              arrsize_t right)
 {
     std::sort(arg + left,
               arg + right,
@@ -53,7 +58,7 @@ std_argsort_withnan(T *arr, arrsize_t *arg, arrsize_t left, arrsize_t right)
 /* argsort using std::sort */
 template <typename T>
 X86_SIMD_SORT_INLINE void
-std_argsort(T *arr, arrsize_t *arg, arrsize_t left, arrsize_t right)
+std_argsort(const T *arr, arrsize_t *arg, arrsize_t left, arrsize_t right)
 {
     std::sort(arg + left,
               arg + right,
@@ -172,7 +177,7 @@ X86_SIMD_SORT_INLINE int32_t partition_vec(type_t *arg,
  * last element that is less than equal to the pivot.
  */
 template <typename vtype, typename argtype, typename type_t>
-X86_SIMD_SORT_INLINE arrsize_t argpartition(type_t *arr,
+X86_SIMD_SORT_INLINE arrsize_t argpartition(const type_t *arr,
                                             arrsize_t *arg,
                                             arrsize_t left,
                                             arrsize_t right,
@@ -291,7 +296,7 @@ template <typename vtype,
           typename argtype,
           int num_unroll,
           typename type_t = typename vtype::type_t>
-X86_SIMD_SORT_INLINE arrsize_t argpartition_unrolled(type_t *arr,
+X86_SIMD_SORT_INLINE arrsize_t argpartition_unrolled(const type_t *arr,
                                                      arrsize_t *arg,
                                                      arrsize_t left,
                                                      arrsize_t right,
@@ -422,7 +427,7 @@ X86_SIMD_SORT_INLINE arrsize_t argpartition_unrolled(type_t *arr,
 }
 
 template <typename vtype, typename type_t>
-X86_SIMD_SORT_INLINE type_t get_pivot_64bit(type_t *arr,
+X86_SIMD_SORT_INLINE type_t get_pivot_64bit(const type_t *arr,
                                             arrsize_t *arg,
                                             const arrsize_t left,
                                             const arrsize_t right)
@@ -468,7 +473,7 @@ X86_SIMD_SORT_INLINE type_t get_pivot_64bit(type_t *arr,
 }
 
 template <typename vtype, typename argtype, typename type_t>
-X86_SIMD_SORT_INLINE void argsort_(type_t *arr,
+X86_SIMD_SORT_INLINE void argsort_(const type_t *arr,
                                    arrsize_t *arg,
                                    arrsize_t left,
                                    arrsize_t right,
@@ -549,7 +554,7 @@ X86_SIMD_SORT_INLINE void argsort_(type_t *arr,
 }
 
 template <typename vtype, typename argtype, typename type_t>
-X86_SIMD_SORT_INLINE void argselect_(type_t *arr,
+X86_SIMD_SORT_INLINE void argselect_(const type_t *arr,
                                      arrsize_t *arg,
                                      arrsize_t pos,
                                      arrsize_t left,
@@ -590,7 +595,7 @@ template <typename T,
           typename full_vector,
           template <typename...>
           typename half_vector>
-X86_SIMD_SORT_INLINE void xss_argsort(T *arr,
+X86_SIMD_SORT_INLINE void xss_argsort(const T *arr,
                                       arrsize_t *arg,
                                       arrsize_t arrsize,
                                       bool hasnan = false,
@@ -669,29 +674,25 @@ X86_SIMD_SORT_INLINE void xss_argsort(T *arr,
 }
 
 template <typename T>
-X86_SIMD_SORT_INLINE void avx512_argsort(T *arr,
+X86_SIMD_SORT_INLINE void avx512_argsort(const T *arr,
                                          arrsize_t *arg,
                                          arrsize_t arrsize,
                                          bool hasnan = false,
                                          bool descending = false)
 {
-    // Safe: argsort never mutates arr; const is dropped only for SIMD type instantiation
-    using base_t = std::remove_const_t<T>;
-    xss_argsort<base_t, zmm_vector, ymm_vector>(
-            const_cast<base_t *>(arr), arg, arrsize, hasnan, descending);
+    xss_argsort<T, zmm_vector, ymm_vector>(
+            arr, arg, arrsize, hasnan, descending);
 }
 
 template <typename T>
-X86_SIMD_SORT_INLINE void avx2_argsort(T *arr,
+X86_SIMD_SORT_INLINE void avx2_argsort(const T *arr,
                                        arrsize_t *arg,
                                        arrsize_t arrsize,
                                        bool hasnan = false,
                                        bool descending = false)
 {
-    // Safe: argsort never mutates arr; const is dropped only for SIMD type instantiation
-    using base_t = std::remove_const_t<T>;
-    xss_argsort<base_t, avx2_vector, avx2_half_vector>(
-            const_cast<base_t *>(arr), arg, arrsize, hasnan, descending);
+    xss_argsort<T, avx2_vector, avx2_half_vector>(
+            arr, arg, arrsize, hasnan, descending);
 }
 
 /* argselect methods for 32-bit and 64-bit dtypes */
@@ -700,7 +701,7 @@ template <typename T,
           typename full_vector,
           template <typename...>
           typename half_vector>
-X86_SIMD_SORT_INLINE void xss_argselect(T *arr,
+X86_SIMD_SORT_INLINE void xss_argselect(const T *arr,
                                         arrsize_t *arg,
                                         arrsize_t k,
                                         arrsize_t arrsize,
@@ -735,29 +736,24 @@ X86_SIMD_SORT_INLINE void xss_argselect(T *arr,
 }
 
 template <typename T>
-X86_SIMD_SORT_INLINE void avx512_argselect(T *arr,
+X86_SIMD_SORT_INLINE void avx512_argselect(const T *arr,
                                            arrsize_t *arg,
                                            arrsize_t k,
                                            arrsize_t arrsize,
                                            bool hasnan = false)
 {
-    // Safe: argselect never mutates arr; const is dropped only for SIMD type instantiation
-    using base_t = std::remove_const_t<T>;
-    xss_argselect<base_t, zmm_vector, ymm_vector>(
-            const_cast<base_t *>(arr), arg, k, arrsize, hasnan);
+    xss_argselect<T, zmm_vector, ymm_vector>(arr, arg, k, arrsize, hasnan);
 }
 
 template <typename T>
-X86_SIMD_SORT_INLINE void avx2_argselect(T *arr,
+X86_SIMD_SORT_INLINE void avx2_argselect(const T *arr,
                                          arrsize_t *arg,
                                          arrsize_t k,
                                          arrsize_t arrsize,
                                          bool hasnan = false)
 {
-    // Safe: argselect never mutates arr; const is dropped only for SIMD type instantiation
-    using base_t = std::remove_const_t<T>;
-    xss_argselect<base_t, avx2_vector, avx2_half_vector>(
-            const_cast<base_t *>(arr), arg, k, arrsize, hasnan);
+    xss_argselect<T, avx2_vector, avx2_half_vector>(
+            arr, arg, k, arrsize, hasnan);
 }
 
 #endif // XSS_COMMON_ARGSORT
diff --git a/src/xss-common-qsort.h b/src/xss-common-qsort.h
index 73b947a..2bf7ca6 100644
--- a/src/xss-common-qsort.h
+++ b/src/xss-common-qsort.h
@@ -79,7 +79,7 @@ X86_SIMD_SORT_INLINE arrsize_t replace_nan_with_inf(T *arr, arrsize_t size)
 }
 
 template <typename vtype, typename type_t>
-X86_SIMD_SORT_INLINE bool array_has_nan(type_t *arr, arrsize_t size)
+X86_SIMD_SORT_INLINE bool array_has_nan(const type_t *arr, arrsize_t size)
 {
     using opmask_t = typename vtype::opmask_t;
     using reg_t = typename vtype::reg_t;
diff --git a/src/xss-network-keyvaluesort.hpp b/src/xss-network-keyvaluesort.hpp
index 771d7a3..1e5cd5d 100644
--- a/src/xss-network-keyvaluesort.hpp
+++ b/src/xss-network-keyvaluesort.hpp
@@ -208,7 +208,7 @@ bitonic_fullmerge_n_vec(typename keyType::reg_t *keys,
 
 template <typename keyType, typename indexType, int numVecs>
 X86_SIMD_SORT_INLINE void
-argsort_n_vec(typename keyType::type_t *keys, arrsize_t *indices, int N)
+argsort_n_vec(const typename keyType::type_t *keys, arrsize_t *indices, int N)
 {
     using kreg_t = typename keyType::reg_t;
     using ireg_t = typename indexType::reg_t;
@@ -354,7 +354,7 @@ X86_SIMD_SORT_INLINE void kvsort_n_vec(typename keyType::type_t *keys,
 
 template <typename keyType, typename indexType, int maxN>
 X86_SIMD_SORT_INLINE void
-argsort_n(typename keyType::type_t *keys, arrsize_t *indices, int N)
+argsort_n(const typename keyType::type_t *keys, arrsize_t *indices, int N)
 {
     static_assert(keyType::numlanes == indexType::numlanes,
                   "invalid pairing of value/index types");