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Float16.cu
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 #include "Float16.cuh"
11 #include "nvidia/fp16_emu.cuh"
12 #include <thrust/execution_policy.h>
13 #include <thrust/transform.h>
14
15 #ifdef FAISS_USE_FLOAT16
16
17 namespace faiss { namespace gpu {
18
19 bool getDeviceSupportsFloat16Math(int device) {
20 const auto& prop = getDeviceProperties(device);
21
22 return (prop.major >= 6 ||
23 (prop.major == 5 && prop.minor >= 3));
24 }
25
26 struct FloatToHalf {
27 __device__ half operator()(float v) const { return __float2half(v); }
28 };
29
30 struct HalfToFloat {
31 __device__ float operator()(half v) const { return __half2float(v); }
32 };
33
34 void runConvertToFloat16(half* out,
35 const float* in,
36 size_t num,
37 cudaStream_t stream) {
38 thrust::transform(thrust::cuda::par.on(stream),
39 in, in + num, out, FloatToHalf());
40 }
41
42 void runConvertToFloat32(float* out,
43 const half* in,
44 size_t num,
45 cudaStream_t stream) {
46 thrust::transform(thrust::cuda::par.on(stream),
47 in, in + num, out, HalfToFloat());
48 }
49
50 __half hostFloat2Half(float a) {
51 #if CUDA_VERSION >= 9000
52 __half_raw raw;
53 raw.x = cpu_float2half_rn(a).x;
54 return __half(raw);
55 #else
56 __half h;
57 h.x = cpu_float2half_rn(a).x;
58 return h;
59 #endif
60 }
61
62 } } // namespace
63
64 #endif // FAISS_USE_FLOAT16