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Limits.cuh
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD+Patents license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include "Float16.cuh"
#include "Pair.cuh"
#include <limits>
namespace faiss { namespace gpu {
template <typename T>
struct Limits {
};
// Unfortunately we can't use constexpr because there is no
// constexpr constructor for half
// FIXME: faiss CPU uses +/-FLT_MAX instead of +/-infinity
constexpr float kFloatMax = std::numeric_limits<float>::max();
constexpr float kFloatMin = std::numeric_limits<float>::lowest();
template <>
struct Limits<float> {
static __device__ __host__ inline float getMin() {
return kFloatMin;
}
static __device__ __host__ inline float getMax() {
return kFloatMax;
}
};
#ifdef FAISS_USE_FLOAT16
inline __device__ __host__ half kGetHalf(unsigned short v) {
#if CUDA_VERSION >= 9000
__half_raw h;
h.x = v;
return __half(h);
#else
half h;
h.x = v;
return h;
#endif
}
template <>
struct Limits<half> {
static __device__ __host__ inline half getMin() {
return kGetHalf(0xfbffU);
}
static __device__ __host__ inline half getMax() {
return kGetHalf(0x7bffU);
}
};
#endif // FAISS_USE_FLOAT16
constexpr int kIntMax = std::numeric_limits<int>::max();
constexpr int kIntMin = std::numeric_limits<int>::lowest();
template <>
struct Limits<int> {
static __device__ __host__ inline int getMin() {
return kIntMin;
}
static __device__ __host__ inline int getMax() {
return kIntMax;
}
};
template<typename K, typename V>
struct Limits<Pair<K, V>> {
static __device__ __host__ inline Pair<K, V> getMin() {
return Pair<K, V>(Limits<K>::getMin(), Limits<V>::getMin());
}
static __device__ __host__ inline Pair<K, V> getMax() {
return Pair<K, V>(Limits<K>::getMax(), Limits<V>::getMax());
}
};
} } // namespace
faiss::gpu::Pair
A simple pair type for CUDA device usage.
Definition: Pair.cuh:20
faiss::gpu::Limits
Definition: Limits.cuh:19