1/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7    http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15
16#ifndef TENSORFLOW_STREAM_EXECUTOR_RNG_H_
17#define TENSORFLOW_STREAM_EXECUTOR_RNG_H_
18
19#include <limits.h>
20#include <complex>
21
22#include "tensorflow/stream_executor/platform/logging.h"
23#include "tensorflow/stream_executor/platform/port.h"
24
25namespace perftools {
26namespace gputools {
27
28class Stream;
29template <typename ElemT>
30class DeviceMemory;
31
32namespace rng {
33
34// Random-number-generation support interface -- this can be derived from a GPU
35// executor when the underlying platform has an RNG library implementation
36// available. See StreamExecutor::AsRng().
37// When a seed is not specified, the backing RNG will be initialized with the
38// default seed for that implementation.
39//
40// Thread-hostile: see StreamExecutor class comment for details on
41// thread-hostility.
42class RngSupport {
43 public:
44  static const int kMinSeedBytes = 16;
45  static const int kMaxSeedBytes = INT_MAX;
46
47  // Releases any random-number-generation resources associated with this
48  // support object in the underlying platform implementation.
49  virtual ~RngSupport() {}
50
51  // Populates a GPU memory allocation with random values appropriate for the
52  // DeviceMemory element type; i.e. populates DeviceMemory<float> with random
53  // float values.
54  virtual bool DoPopulateRandUniform(Stream *stream,
55                                     DeviceMemory<float> *v) = 0;
56  virtual bool DoPopulateRandUniform(Stream *stream,
57                                     DeviceMemory<double> *v) = 0;
58  virtual bool DoPopulateRandUniform(Stream *stream,
59                                     DeviceMemory<std::complex<float>> *v) = 0;
60  virtual bool DoPopulateRandUniform(Stream *stream,
61                                     DeviceMemory<std::complex<double>> *v) = 0;
62
63  // Populates a GPU memory allocation with random values sampled from a
64  // Gaussian distribution with the given mean and standard deviation.
65  virtual bool DoPopulateRandGaussian(Stream *stream, float mean, float stddev,
66                                      DeviceMemory<float> *v) {
67    LOG(ERROR)
68        << "platform's random number generator does not support gaussian";
69    return false;
70  }
71  virtual bool DoPopulateRandGaussian(Stream *stream, double mean,
72                                      double stddev, DeviceMemory<double> *v) {
73    LOG(ERROR)
74        << "platform's random number generator does not support gaussian";
75    return false;
76  }
77
78  // Specifies the seed used to initialize the RNG.
79  // This call does not transfer ownership of the buffer seed; its data should
80  // not be altered for the lifetime of this call. At least 16 bytes of seed
81  // data must be provided, but not all seed data will necessarily be used.
82  // seed: Pointer to seed data. Must not be null.
83  // seed_bytes: Size of seed buffer in bytes. Must be >= 16.
84  virtual bool SetSeed(Stream *stream, const uint8 *seed,
85                       uint64 seed_bytes) = 0;
86
87 protected:
88  static bool CheckSeed(const uint8 *seed, uint64 seed_bytes);
89};
90
91}  // namespace rng
92}  // namespace gputools
93}  // namespace perftools
94
95#endif  // TENSORFLOW_STREAM_EXECUTOR_RNG_H_
96