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16
17/// @example softmax.cpp
18/// > Annotated version: @ref softmax_example_cpp
19///
20/// @page softmax_example_cpp_short
21///
22/// This C++ API example demonstrates how to create and execute a
23/// [Softmax](@ref dev_guide_softmax) primitive in forward training propagation
24/// mode.
25///
26/// Key optimizations included in this example:
27/// - In-place primitive execution;
28/// - Softmax along axis 1 (C) for 2D tensors.
29///
30/// @page softmax_example_cpp Softmax Primitive Example
31/// @copydetails softmax_example_cpp_short
32///
33/// @include softmax.cpp
34
35#include <algorithm>
36#include <cmath>
37#include <iostream>
38#include <string>
39#include <vector>
40
41#include "example_utils.hpp"
42#include "oneapi/dnnl/dnnl.hpp"
43
44using namespace dnnl;
45
46using tag = memory::format_tag;
47using dt = memory::data_type;
48
49void softmax_example(dnnl::engine::kind engine_kind) {
50
51 // Create execution dnnl::engine.
52 dnnl::engine engine(engine_kind, 0);
53
54 // Create dnnl::stream.
55 dnnl::stream engine_stream(engine);
56
57 // Tensor dimensions.
58 const memory::dim N = 3, // batch size
59 IC = 1000; // channels
60
61 // Source (src) and destination (dst) tensors dimensions.
62 memory::dims src_dims = {N, IC};
63
64 // Allocate buffer.
65 std::vector<float> src_data(product(src_dims));
66
67 std::generate(src_data.begin(), src_data.end(), []() {
68 static int i = 0;
69 return std::cos(i++ / 10.f);
70 });
71
72 // Create src memory descriptor and memory object.
73 auto src_md = memory::desc(src_dims, dt::f32, tag::nc);
74 auto dst_md = memory::desc(src_dims, dt::f32, tag::nc);
75 auto src_mem = memory(src_md, engine);
76
77 // Write data to memory object's handle.
78 write_to_dnnl_memory(src_data.data(), src_mem);
79
80 // Softmax axis.
81 const int axis = 1;
82
83 // Create primitive descriptor.
84 auto softmax_pd = softmax_forward::primitive_desc(engine,
85 prop_kind::forward_training, algorithm::softmax_accurate, src_md,
86 dst_md, axis);
87
88 // Create the primitive.
89 auto softmax_prim = softmax_forward(softmax_pd);
90
91 // Primitive arguments. Set up in-place execution by assigning src as DST.
92 std::unordered_map<int, memory> softmax_args;
93 softmax_args.insert({DNNL_ARG_SRC, src_mem});
94 softmax_args.insert({DNNL_ARG_DST, src_mem});
95
96 // Primitive execution.
97 softmax_prim.execute(engine_stream, softmax_args);
98
99 // Wait for the computation to finalize.
100 engine_stream.wait();
101
102 // Read data from memory object's handle.
103 read_from_dnnl_memory(src_data.data(), src_mem);
104}
105
106int main(int argc, char **argv) {
107 return handle_example_errors(
108 softmax_example, parse_engine_kind(argc, argv));
109}
110