1 // Copyright (c) 2010-2021, Lawrence Livermore National Security, LLC. Produced
2 // at the Lawrence Livermore National Laboratory. All Rights reserved. See files
3 // LICENSE and NOTICE for details. LLNL-CODE-806117.
4 //
5 // This file is part of the MFEM library. For more information and source code
6 // availability visit https://mfem.org.
7 //
8 // MFEM is free software; you can redistribute it and/or modify it under the
9 // terms of the BSD-3 license. We welcome feedback and contributions, see file
10 // CONTRIBUTING.md for details.
11 
12 #ifndef MFEM_TMOP_PA_HPP
13 #define MFEM_TMOP_PA_HPP
14 
15 #include "../../config/config.hpp"
16 #include "../../linalg/dtensor.hpp"
17 
18 #include "../kernels.hpp"
19 
20 #include <unordered_map>
21 
22 namespace mfem
23 {
24 
25 namespace kernels
26 {
27 
28 template <typename K> class KernelMap;
29 
30 /// Instances
31 template<class K, int N = K::N> struct Instances
32 {
Fillmfem::kernels::Instances33    static void Fill(KernelMap<K> &map)
34    {
35       map.template Emplace<N-1>();
36       Instances<K,N-1>::Fill(map);
37    }
38 };
39 
40 // terminal case
41 template<class K> struct Instances<K,1>
42 {
Fillmfem::kernels::Instances43    static void Fill(KernelMap<K> &map) { map.template Emplace<0>(); }
44 };
45 
46 /// KernelMap class which creates an unordered_map of the Keys/Kernels
47 template<class K>
48 class KernelMap
49 {
50    using Key_t = typename K::Key_t;
51    using Return_t = typename K::Return_t;
52    using Kernel_t = typename K::Kernel_t;
53    using map_t = std::unordered_map<Key_t, Kernel_t>;
54    map_t map;
55 
56 public:
57    // Fill all the map with the Keys/Kernels
KernelMap()58    KernelMap() { Instances<K>::Fill(*this); }
59 
Find(const Key_t id)60    bool Find(const Key_t id) { return map.find(id) != map.end(); }
61 
At(const Key_t id)62    Kernel_t At(const Key_t id) { return map.at(id); }
63 
Emplace()64    template<int N> void Emplace()
65    {
66       constexpr Key_t key = K::template GetKey<N>();
67       constexpr Kernel_t ker = K::template GetKer<key>();
68       map.emplace(key, ker);
69    }
70 };
71 
72 // /////////////////////////////////////////////////////////////////////////////
73 // MFEM_REGISTER_TMOP_KERNELS macro:
74 //  - the first argument (return_t) is the return type of the kernel
75 //  - the second argument (kernel) is the name of the kernel
76 //  - the arguments of the kernel (...) captured as __VA_ARGS__
77 //
78 // This call will output the followings:
79 //  1. forward declaration of the kernel
80 //  2. kernel pointer declaration
81 //  3. struct K##name##_T definition which holds the keys/kernels map
82 //  4. KernelMap definition of the current kernel
83 //  5. the kernel signature by re-using all the arguments
84 //
85 // /////////////////////////////////////////////////////////////////////////////
86 // For example:
87 // MFEM_REGISTER_TMOP_KERNELS(void, Name,
88 //                            const int NE,
89 //                            const Array<double> &b,
90 //                            Vector &diagonal,
91 //                            const int d1d,
92 //                            const int q1d) {...}
93 //
94 // The resulting code would be:
95 //
96 // 1. forward declaration of the kernel
97 // template<int T_D1D = 0, int T_Q1D = 0, int T_MAX = 0>
98 // void Name(const int NE,
99 //           const Array<double> &b,
100 //           Vector &diagonal,
101 //           const int d1d,
102 //           const int q1d);
103 //
104 // 2. kernel pointer declaration
105 // typedef void (*Name_p)(const int NE,
106 //                        const Array<double> &b,
107 //                        Vector &diagonal,
108 //                        const int d1d,
109 //                        const int q1d);
110 //
111 // 3. struct K##Name##_T definition which holds the keys/kernels instance
112 // struct KName_T
113 // {
114 //    static const int N = 14;
115 //    using Key_t = int;
116 //    using Return_t = void;
117 //    using Kernel_t = Name_p;
118 //    template<Key_t I> static constexpr Key_t GetKey() noexcept
119 //    {
120 //       return I==0 ? 0x22 : I==1 ? 0x23 : I==2 ? 0x24 : I==3 ? 0x25 :
121 //              I==4 ? 0x26 : I== 5 ? 0x33 : I==6 ? 0x34 : I==7 ? 0x35 :
122 //              I==8 ? 0x36 : I==9 ? 0x44 : I==10 ? 0x45 : I==11 ? 0x46 :
123 //              I==12 ? 0x55 : I==13 ? 0x56 : 0;
124 //    }
125 //    template<Key_t K> static constexpr Kernel_t GetKer() noexcept
126 //    {
127 //       return &AssembleDiagonalPA_Kernel_2D<(K>>4)&0xF, K&0xF>;
128 //    }
129 // };
130 //
131 // 4. KernelMap definition of the current kernel
132 // static kernels::KernelMap<KName_T> KName;
133 //
134 // 5. the kernel signature by re-using all the arguments
135 // template<int T_D1D, int T_Q1D, int T_MAX>
136 // void Name(const int NE,
137 //           const Array<double> &b,
138 //           Vector &diagonal,
139 //           const int d1d,
140 //           const int q1d) {...}
141 
142 // /////////////////////////////////////////////////////////////////////////////
143 // All of which allows to launch the kernel with a specific id ((D1D<<4)|Q1D).
144 //
145 // For example, a MFEM_LAUNCH_TMOP_KERNEL(Name,id,NE,B,D); call would result in:
146 //
147 // if (KName.Find(id)) { return KName.At(id)(NE,B,D,0,0); }
148 // else
149 // {
150 //    constexpr int T_MAX = 4;
151 //    const int D1D = (id>>4)&0xF, Q1D = id&0xF;
152 //    MFEM_VERIFY(D1D <= MAX_D1D && Q1D <= MAX_Q1D, "Max size error!");
153 //    return Name<0,0,T_MAX>(NE,B,D,D1D,Q1D);
154 // };
155 
156 #define MFEM_REGISTER_TMOP_KERNELS(return_t, kernel, ...) \
157 template<int T_D1D = 0, int T_Q1D = 0, int T_MAX = 0> \
158     return_t kernel(__VA_ARGS__);\
159 typedef return_t (*kernel##_p)(__VA_ARGS__);\
160 struct K##kernel##_T {\
161    static const int N = 14;\
162    using Key_t = int;\
163    using Return_t = return_t;\
164    using Kernel_t = kernel##_p;\
165    template<Key_t I> static constexpr Key_t GetKey() noexcept { return \
166      I==0 ? 0x22 : I==1 ? 0x23 : I==2 ? 0x24 : I==3 ? 0x25 : I==4 ? 0x26 :\
167      I==5 ? 0x33 : I==6 ? 0x34 : I==7 ? 0x35 : I==8 ? 0x36  :\
168      I==9 ? 0x44 : I==10 ? 0x45 : I==11 ? 0x46 :\
169      I==12 ? 0x55 : I==13 ? 0x56 : 0; }\
170    template<Key_t K> static constexpr Kernel_t GetKer() noexcept\
171    { return &kernel<(K>>4)&0xF, K&0xF>; }\
172 };\
173 static kernels::KernelMap<K##kernel##_T> K##kernel;\
174 template<int T_D1D, int T_Q1D, int T_MAX> return_t kernel(__VA_ARGS__)
175 
176 // MFEM_LAUNCH_TMOP_KERNEL macro
177 // This macro will try to find and launch the kernel with the id key and
178 // the templated arguments.
179 // If not, it will fall back to the kernel with the standard arguments.
180 #define MFEM_LAUNCH_TMOP_KERNEL(kernel, id, ...)\
181 if (K##kernel.Find(id)) { return K##kernel.At(id)(__VA_ARGS__,0,0); }\
182 else {\
183    constexpr int T_MAX = 4;\
184    const int D1D = (id>>4)&0xF, Q1D = id&0xF;\
185    MFEM_VERIFY(D1D <= MAX_D1D && Q1D <= MAX_Q1D, "Max size error!");\
186    return kernel<0,0,T_MAX>(__VA_ARGS__,D1D,Q1D); }
187 
188 } // namespace kernels
189 
190 } // namespace mfem
191 
192 #endif // MFEM_TMOP_PA_HPP
193