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Comparators.cuh
1 /**
2  * Copyright (c) 2015-present, Facebook, Inc.
3  * All rights reserved.
4  *
5  * This source code is licensed under the BSD+Patents license found in the
6  * LICENSE file in the root directory of this source tree.
7  */
8 
9 
10 #pragma once
11 
12 #include <cuda.h>
13 #include "Float16.cuh"
14 
15 namespace faiss { namespace gpu {
16 
17 template <typename T>
18 struct Comparator {
19  __device__ static inline bool lt(T a, T b) {
20  return a < b;
21  }
22 
23  __device__ static inline bool gt(T a, T b) {
24  return a > b;
25  }
26 };
27 
28 #ifdef FAISS_USE_FLOAT16
29 
30 template <>
31 struct Comparator<half> {
32  __device__ static inline bool lt(half a, half b) {
33 #if FAISS_USE_FULL_FLOAT16
34  return __hlt(a, b);
35 #else
36  return __half2float(a) < __half2float(b);
37 #endif // FAISS_USE_FULL_FLOAT16
38  }
39 
40  __device__ static inline bool gt(half a, half b) {
41 #if FAISS_USE_FULL_FLOAT16
42  return __hgt(a, b);
43 #else
44  return __half2float(a) > __half2float(b);
45 #endif // FAISS_USE_FULL_FLOAT16
46  }
47 };
48 
49 #endif // FAISS_USE_FLOAT16
50 
51 } } // namespace