CXX11Meta.h (22752B)
1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2013 Christian Seiler <christian@iwakd.de> 5 // 6 // This Source Code Form is subject to the terms of the Mozilla 7 // Public License v. 2.0. If a copy of the MPL was not distributed 8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 9 10 #ifndef EIGEN_CXX11META_H 11 #define EIGEN_CXX11META_H 12 13 #include <vector> 14 #include "EmulateArray.h" 15 16 #include "CXX11Workarounds.h" 17 18 namespace Eigen { 19 20 namespace internal { 21 22 /** \internal 23 * \file CXX11/util/CXX11Meta.h 24 * This file contains generic metaprogramming classes which are not specifically related to Eigen. 25 * This file expands upon Core/util/Meta.h and adds support for C++11 specific features. 26 */ 27 28 template<typename... tt> 29 struct type_list { constexpr static int count = sizeof...(tt); }; 30 31 template<typename t, typename... tt> 32 struct type_list<t, tt...> { constexpr static int count = sizeof...(tt) + 1; typedef t first_type; }; 33 34 template<typename T, T... nn> 35 struct numeric_list { constexpr static std::size_t count = sizeof...(nn); }; 36 37 template<typename T, T n, T... nn> 38 struct numeric_list<T, n, nn...> { static const std::size_t count = sizeof...(nn) + 1; const static T first_value = n; }; 39 40 #ifndef EIGEN_PARSED_BY_DOXYGEN 41 /* numeric list constructors 42 * 43 * equivalencies: 44 * constructor result 45 * typename gen_numeric_list<int, 5>::type numeric_list<int, 0,1,2,3,4> 46 * typename gen_numeric_list_reversed<int, 5>::type numeric_list<int, 4,3,2,1,0> 47 * typename gen_numeric_list_swapped_pair<int, 5,1,2>::type numeric_list<int, 0,2,1,3,4> 48 * typename gen_numeric_list_repeated<int, 0, 5>::type numeric_list<int, 0,0,0,0,0> 49 */ 50 51 template<typename T, std::size_t n, T start = 0, T... ii> struct gen_numeric_list : gen_numeric_list<T, n-1, start, start + n-1, ii...> {}; 52 template<typename T, T start, T... ii> struct gen_numeric_list<T, 0, start, ii...> { typedef numeric_list<T, ii...> type; }; 53 54 template<typename T, std::size_t n, T start = 0, T... ii> struct gen_numeric_list_reversed : gen_numeric_list_reversed<T, n-1, start, ii..., start + n-1> {}; 55 template<typename T, T start, T... ii> struct gen_numeric_list_reversed<T, 0, start, ii...> { typedef numeric_list<T, ii...> type; }; 56 57 template<typename T, std::size_t n, T a, T b, T start = 0, T... ii> struct gen_numeric_list_swapped_pair : gen_numeric_list_swapped_pair<T, n-1, a, b, start, (start + n-1) == a ? b : ((start + n-1) == b ? a : (start + n-1)), ii...> {}; 58 template<typename T, T a, T b, T start, T... ii> struct gen_numeric_list_swapped_pair<T, 0, a, b, start, ii...> { typedef numeric_list<T, ii...> type; }; 59 60 template<typename T, std::size_t n, T V, T... nn> struct gen_numeric_list_repeated : gen_numeric_list_repeated<T, n-1, V, V, nn...> {}; 61 template<typename T, T V, T... nn> struct gen_numeric_list_repeated<T, 0, V, nn...> { typedef numeric_list<T, nn...> type; }; 62 63 /* list manipulation: concatenate */ 64 65 template<class a, class b> struct concat; 66 67 template<typename... as, typename... bs> struct concat<type_list<as...>, type_list<bs...>> { typedef type_list<as..., bs...> type; }; 68 template<typename T, T... as, T... bs> struct concat<numeric_list<T, as...>, numeric_list<T, bs...> > { typedef numeric_list<T, as..., bs...> type; }; 69 70 template<typename... p> struct mconcat; 71 template<typename a> struct mconcat<a> { typedef a type; }; 72 template<typename a, typename b> struct mconcat<a, b> : concat<a, b> {}; 73 template<typename a, typename b, typename... cs> struct mconcat<a, b, cs...> : concat<a, typename mconcat<b, cs...>::type> {}; 74 75 /* list manipulation: extract slices */ 76 77 template<int n, typename x> struct take; 78 template<int n, typename a, typename... as> struct take<n, type_list<a, as...>> : concat<type_list<a>, typename take<n-1, type_list<as...>>::type> {}; 79 template<int n> struct take<n, type_list<>> { typedef type_list<> type; }; 80 template<typename a, typename... as> struct take<0, type_list<a, as...>> { typedef type_list<> type; }; 81 template<> struct take<0, type_list<>> { typedef type_list<> type; }; 82 83 template<typename T, int n, T a, T... as> struct take<n, numeric_list<T, a, as...>> : concat<numeric_list<T, a>, typename take<n-1, numeric_list<T, as...>>::type> {}; 84 template<typename T, int n> struct take<n, numeric_list<T>> { typedef numeric_list<T> type; }; 85 template<typename T, T a, T... as> struct take<0, numeric_list<T, a, as...>> { typedef numeric_list<T> type; }; 86 template<typename T> struct take<0, numeric_list<T>> { typedef numeric_list<T> type; }; 87 88 template<typename T, int n, T... ii> struct h_skip_helper_numeric; 89 template<typename T, int n, T i, T... ii> struct h_skip_helper_numeric<T, n, i, ii...> : h_skip_helper_numeric<T, n-1, ii...> {}; 90 template<typename T, T i, T... ii> struct h_skip_helper_numeric<T, 0, i, ii...> { typedef numeric_list<T, i, ii...> type; }; 91 template<typename T, int n> struct h_skip_helper_numeric<T, n> { typedef numeric_list<T> type; }; 92 template<typename T> struct h_skip_helper_numeric<T, 0> { typedef numeric_list<T> type; }; 93 94 template<int n, typename... tt> struct h_skip_helper_type; 95 template<int n, typename t, typename... tt> struct h_skip_helper_type<n, t, tt...> : h_skip_helper_type<n-1, tt...> {}; 96 template<typename t, typename... tt> struct h_skip_helper_type<0, t, tt...> { typedef type_list<t, tt...> type; }; 97 template<int n> struct h_skip_helper_type<n> { typedef type_list<> type; }; 98 template<> struct h_skip_helper_type<0> { typedef type_list<> type; }; 99 #endif //not EIGEN_PARSED_BY_DOXYGEN 100 101 template<int n> 102 struct h_skip { 103 template<typename T, T... ii> 104 constexpr static EIGEN_STRONG_INLINE typename h_skip_helper_numeric<T, n, ii...>::type helper(numeric_list<T, ii...>) { return typename h_skip_helper_numeric<T, n, ii...>::type(); } 105 template<typename... tt> 106 constexpr static EIGEN_STRONG_INLINE typename h_skip_helper_type<n, tt...>::type helper(type_list<tt...>) { return typename h_skip_helper_type<n, tt...>::type(); } 107 }; 108 109 template<int n, typename a> struct skip { typedef decltype(h_skip<n>::helper(a())) type; }; 110 111 template<int start, int count, typename a> struct slice : take<count, typename skip<start, a>::type> {}; 112 113 /* list manipulation: retrieve single element from list */ 114 115 template<int n, typename x> struct get; 116 117 template<int n, typename a, typename... as> struct get<n, type_list<a, as...>> : get<n-1, type_list<as...>> {}; 118 template<typename a, typename... as> struct get<0, type_list<a, as...>> { typedef a type; }; 119 120 template<typename T, int n, T a, T... as> struct get<n, numeric_list<T, a, as...>> : get<n-1, numeric_list<T, as...>> {}; 121 template<typename T, T a, T... as> struct get<0, numeric_list<T, a, as...>> { constexpr static T value = a; }; 122 123 template<std::size_t n, typename T, T a, T... as> constexpr T array_get(const numeric_list<T, a, as...>&) { 124 return get<(int)n, numeric_list<T, a, as...>>::value; 125 } 126 127 /* always get type, regardless of dummy; good for parameter pack expansion */ 128 129 template<typename T, T dummy, typename t> struct id_numeric { typedef t type; }; 130 template<typename dummy, typename t> struct id_type { typedef t type; }; 131 132 /* equality checking, flagged version */ 133 134 template<typename a, typename b> struct is_same_gf : is_same<a, b> { constexpr static int global_flags = 0; }; 135 136 /* apply_op to list */ 137 138 template< 139 bool from_left, // false 140 template<typename, typename> class op, 141 typename additional_param, 142 typename... values 143 > 144 struct h_apply_op_helper { typedef type_list<typename op<values, additional_param>::type...> type; }; 145 template< 146 template<typename, typename> class op, 147 typename additional_param, 148 typename... values 149 > 150 struct h_apply_op_helper<true, op, additional_param, values...> { typedef type_list<typename op<additional_param, values>::type...> type; }; 151 152 template< 153 bool from_left, 154 template<typename, typename> class op, 155 typename additional_param 156 > 157 struct h_apply_op 158 { 159 template<typename... values> 160 constexpr static typename h_apply_op_helper<from_left, op, additional_param, values...>::type helper(type_list<values...>) 161 { return typename h_apply_op_helper<from_left, op, additional_param, values...>::type(); } 162 }; 163 164 template< 165 template<typename, typename> class op, 166 typename additional_param, 167 typename a 168 > 169 struct apply_op_from_left { typedef decltype(h_apply_op<true, op, additional_param>::helper(a())) type; }; 170 171 template< 172 template<typename, typename> class op, 173 typename additional_param, 174 typename a 175 > 176 struct apply_op_from_right { typedef decltype(h_apply_op<false, op, additional_param>::helper(a())) type; }; 177 178 /* see if an element is in a list */ 179 180 template< 181 template<typename, typename> class test, 182 typename check_against, 183 typename h_list, 184 bool last_check_positive = false 185 > 186 struct contained_in_list; 187 188 template< 189 template<typename, typename> class test, 190 typename check_against, 191 typename h_list 192 > 193 struct contained_in_list<test, check_against, h_list, true> 194 { 195 constexpr static bool value = true; 196 }; 197 198 template< 199 template<typename, typename> class test, 200 typename check_against, 201 typename a, 202 typename... as 203 > 204 struct contained_in_list<test, check_against, type_list<a, as...>, false> : contained_in_list<test, check_against, type_list<as...>, test<check_against, a>::value> {}; 205 206 template< 207 template<typename, typename> class test, 208 typename check_against 209 EIGEN_TPL_PP_SPEC_HACK_DEFC(typename, empty) 210 > 211 struct contained_in_list<test, check_against, type_list<EIGEN_TPL_PP_SPEC_HACK_USE(empty)>, false> { constexpr static bool value = false; }; 212 213 /* see if an element is in a list and check for global flags */ 214 215 template< 216 template<typename, typename> class test, 217 typename check_against, 218 typename h_list, 219 int default_flags = 0, 220 bool last_check_positive = false, 221 int last_check_flags = default_flags 222 > 223 struct contained_in_list_gf; 224 225 template< 226 template<typename, typename> class test, 227 typename check_against, 228 typename h_list, 229 int default_flags, 230 int last_check_flags 231 > 232 struct contained_in_list_gf<test, check_against, h_list, default_flags, true, last_check_flags> 233 { 234 constexpr static bool value = true; 235 constexpr static int global_flags = last_check_flags; 236 }; 237 238 template< 239 template<typename, typename> class test, 240 typename check_against, 241 typename a, 242 typename... as, 243 int default_flags, 244 int last_check_flags 245 > 246 struct contained_in_list_gf<test, check_against, type_list<a, as...>, default_flags, false, last_check_flags> : contained_in_list_gf<test, check_against, type_list<as...>, default_flags, test<check_against, a>::value, test<check_against, a>::global_flags> {}; 247 248 template< 249 template<typename, typename> class test, 250 typename check_against 251 EIGEN_TPL_PP_SPEC_HACK_DEFC(typename, empty), 252 int default_flags, 253 int last_check_flags 254 > 255 struct contained_in_list_gf<test, check_against, type_list<EIGEN_TPL_PP_SPEC_HACK_USE(empty)>, default_flags, false, last_check_flags> { constexpr static bool value = false; constexpr static int global_flags = default_flags; }; 256 257 /* generic reductions */ 258 259 template< 260 typename Reducer, 261 typename... Ts 262 > struct reduce; 263 264 template< 265 typename Reducer 266 > struct reduce<Reducer> 267 { 268 EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE int run() { return Reducer::Identity; } 269 }; 270 271 template< 272 typename Reducer, 273 typename A 274 > struct reduce<Reducer, A> 275 { 276 EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE A run(A a) { return a; } 277 }; 278 279 template< 280 typename Reducer, 281 typename A, 282 typename... Ts 283 > struct reduce<Reducer, A, Ts...> 284 { 285 EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE auto run(A a, Ts... ts) -> decltype(Reducer::run(a, reduce<Reducer, Ts...>::run(ts...))) { 286 return Reducer::run(a, reduce<Reducer, Ts...>::run(ts...)); 287 } 288 }; 289 290 /* generic binary operations */ 291 292 struct sum_op { 293 template<typename A, typename B> EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a + b) { return a + b; } 294 static constexpr int Identity = 0; 295 }; 296 struct product_op { 297 template<typename A, typename B> EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a * b) { return a * b; } 298 static constexpr int Identity = 1; 299 }; 300 301 struct logical_and_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a && b) { return a && b; } }; 302 struct logical_or_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a || b) { return a || b; } }; 303 304 struct equal_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a == b) { return a == b; } }; 305 struct not_equal_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a != b) { return a != b; } }; 306 struct lesser_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a < b) { return a < b; } }; 307 struct lesser_equal_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a <= b) { return a <= b; } }; 308 struct greater_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a > b) { return a > b; } }; 309 struct greater_equal_op { template<typename A, typename B> constexpr static EIGEN_STRONG_INLINE auto run(A a, B b) -> decltype(a >= b) { return a >= b; } }; 310 311 /* generic unary operations */ 312 313 struct not_op { template<typename A> constexpr static EIGEN_STRONG_INLINE auto run(A a) -> decltype(!a) { return !a; } }; 314 struct negation_op { template<typename A> constexpr static EIGEN_STRONG_INLINE auto run(A a) -> decltype(-a) { return -a; } }; 315 struct greater_equal_zero_op { template<typename A> constexpr static EIGEN_STRONG_INLINE auto run(A a) -> decltype(a >= 0) { return a >= 0; } }; 316 317 318 /* reductions for lists */ 319 320 // using auto -> return value spec makes ICC 13.0 and 13.1 crash here, so we have to hack it 321 // together in front... (13.0 doesn't work with array_prod/array_reduce/... anyway, but 13.1 322 // does... 323 template<typename... Ts> 324 EIGEN_DEVICE_FUNC constexpr EIGEN_STRONG_INLINE decltype(reduce<product_op, Ts...>::run((*((Ts*)0))...)) arg_prod(Ts... ts) 325 { 326 return reduce<product_op, Ts...>::run(ts...); 327 } 328 329 template<typename... Ts> 330 constexpr EIGEN_STRONG_INLINE decltype(reduce<sum_op, Ts...>::run((*((Ts*)0))...)) arg_sum(Ts... ts) 331 { 332 return reduce<sum_op, Ts...>::run(ts...); 333 } 334 335 /* reverse arrays */ 336 337 template<typename Array, int... n> 338 constexpr EIGEN_STRONG_INLINE Array h_array_reverse(Array arr, numeric_list<int, n...>) 339 { 340 return {{array_get<sizeof...(n) - n - 1>(arr)...}}; 341 } 342 343 template<typename T, std::size_t N> 344 constexpr EIGEN_STRONG_INLINE array<T, N> array_reverse(array<T, N> arr) 345 { 346 return h_array_reverse(arr, typename gen_numeric_list<int, N>::type()); 347 } 348 349 350 /* generic array reductions */ 351 352 // can't reuse standard reduce() interface above because Intel's Compiler 353 // *really* doesn't like it, so we just reimplement the stuff 354 // (start from N - 1 and work down to 0 because specialization for 355 // n == N - 1 also doesn't work in Intel's compiler, so it goes into 356 // an infinite loop) 357 template<typename Reducer, typename T, std::size_t N, std::size_t n = N - 1> 358 struct h_array_reduce { 359 EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE auto run(array<T, N> arr, T identity) -> decltype(Reducer::run(h_array_reduce<Reducer, T, N, n - 1>::run(arr, identity), array_get<n>(arr))) 360 { 361 return Reducer::run(h_array_reduce<Reducer, T, N, n - 1>::run(arr, identity), array_get<n>(arr)); 362 } 363 }; 364 365 template<typename Reducer, typename T, std::size_t N> 366 struct h_array_reduce<Reducer, T, N, 0> 367 { 368 EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE T run(const array<T, N>& arr, T) 369 { 370 return array_get<0>(arr); 371 } 372 }; 373 374 template<typename Reducer, typename T> 375 struct h_array_reduce<Reducer, T, 0> 376 { 377 EIGEN_DEVICE_FUNC constexpr static EIGEN_STRONG_INLINE T run(const array<T, 0>&, T identity) 378 { 379 return identity; 380 } 381 }; 382 383 template<typename Reducer, typename T, std::size_t N> 384 EIGEN_DEVICE_FUNC constexpr EIGEN_STRONG_INLINE auto array_reduce(const array<T, N>& arr, T identity) -> decltype(h_array_reduce<Reducer, T, N>::run(arr, identity)) 385 { 386 return h_array_reduce<Reducer, T, N>::run(arr, identity); 387 } 388 389 /* standard array reductions */ 390 391 template<typename T, std::size_t N> 392 EIGEN_DEVICE_FUNC constexpr EIGEN_STRONG_INLINE auto array_sum(const array<T, N>& arr) -> decltype(array_reduce<sum_op, T, N>(arr, static_cast<T>(0))) 393 { 394 return array_reduce<sum_op, T, N>(arr, static_cast<T>(0)); 395 } 396 397 template<typename T, std::size_t N> 398 EIGEN_DEVICE_FUNC constexpr EIGEN_STRONG_INLINE auto array_prod(const array<T, N>& arr) -> decltype(array_reduce<product_op, T, N>(arr, static_cast<T>(1))) 399 { 400 return array_reduce<product_op, T, N>(arr, static_cast<T>(1)); 401 } 402 403 template<typename t> 404 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE t array_prod(const std::vector<t>& a) { 405 eigen_assert(a.size() > 0); 406 t prod = 1; 407 for (size_t i = 0; i < a.size(); ++i) { prod *= a[i]; } 408 return prod; 409 } 410 411 /* zip an array */ 412 413 template<typename Op, typename A, typename B, std::size_t N, int... n> 414 constexpr EIGEN_STRONG_INLINE array<decltype(Op::run(A(), B())),N> h_array_zip(array<A, N> a, array<B, N> b, numeric_list<int, n...>) 415 { 416 return array<decltype(Op::run(A(), B())),N>{{ Op::run(array_get<n>(a), array_get<n>(b))... }}; 417 } 418 419 template<typename Op, typename A, typename B, std::size_t N> 420 constexpr EIGEN_STRONG_INLINE array<decltype(Op::run(A(), B())),N> array_zip(array<A, N> a, array<B, N> b) 421 { 422 return h_array_zip<Op>(a, b, typename gen_numeric_list<int, N>::type()); 423 } 424 425 /* zip an array and reduce the result */ 426 427 template<typename Reducer, typename Op, typename A, typename B, std::size_t N, int... n> 428 constexpr EIGEN_STRONG_INLINE auto h_array_zip_and_reduce(array<A, N> a, array<B, N> b, numeric_list<int, n...>) -> decltype(reduce<Reducer, typename id_numeric<int,n,decltype(Op::run(A(), B()))>::type...>::run(Op::run(array_get<n>(a), array_get<n>(b))...)) 429 { 430 return reduce<Reducer, typename id_numeric<int,n,decltype(Op::run(A(), B()))>::type...>::run(Op::run(array_get<n>(a), array_get<n>(b))...); 431 } 432 433 template<typename Reducer, typename Op, typename A, typename B, std::size_t N> 434 constexpr EIGEN_STRONG_INLINE auto array_zip_and_reduce(array<A, N> a, array<B, N> b) -> decltype(h_array_zip_and_reduce<Reducer, Op, A, B, N>(a, b, typename gen_numeric_list<int, N>::type())) 435 { 436 return h_array_zip_and_reduce<Reducer, Op, A, B, N>(a, b, typename gen_numeric_list<int, N>::type()); 437 } 438 439 /* apply stuff to an array */ 440 441 template<typename Op, typename A, std::size_t N, int... n> 442 constexpr EIGEN_STRONG_INLINE array<decltype(Op::run(A())),N> h_array_apply(array<A, N> a, numeric_list<int, n...>) 443 { 444 return array<decltype(Op::run(A())),N>{{ Op::run(array_get<n>(a))... }}; 445 } 446 447 template<typename Op, typename A, std::size_t N> 448 constexpr EIGEN_STRONG_INLINE array<decltype(Op::run(A())),N> array_apply(array<A, N> a) 449 { 450 return h_array_apply<Op>(a, typename gen_numeric_list<int, N>::type()); 451 } 452 453 /* apply stuff to an array and reduce */ 454 455 template<typename Reducer, typename Op, typename A, std::size_t N, int... n> 456 constexpr EIGEN_STRONG_INLINE auto h_array_apply_and_reduce(array<A, N> arr, numeric_list<int, n...>) -> decltype(reduce<Reducer, typename id_numeric<int,n,decltype(Op::run(A()))>::type...>::run(Op::run(array_get<n>(arr))...)) 457 { 458 return reduce<Reducer, typename id_numeric<int,n,decltype(Op::run(A()))>::type...>::run(Op::run(array_get<n>(arr))...); 459 } 460 461 template<typename Reducer, typename Op, typename A, std::size_t N> 462 constexpr EIGEN_STRONG_INLINE auto array_apply_and_reduce(array<A, N> a) -> decltype(h_array_apply_and_reduce<Reducer, Op, A, N>(a, typename gen_numeric_list<int, N>::type())) 463 { 464 return h_array_apply_and_reduce<Reducer, Op, A, N>(a, typename gen_numeric_list<int, N>::type()); 465 } 466 467 /* repeat a value n times (and make an array out of it 468 * usage: 469 * array<int, 16> = repeat<16>(42); 470 */ 471 472 template<int n> 473 struct h_repeat 474 { 475 template<typename t, int... ii> 476 constexpr static EIGEN_STRONG_INLINE array<t, n> run(t v, numeric_list<int, ii...>) 477 { 478 return {{ typename id_numeric<int, ii, t>::type(v)... }}; 479 } 480 }; 481 482 template<int n, typename t> 483 constexpr array<t, n> repeat(t v) { return h_repeat<n>::run(v, typename gen_numeric_list<int, n>::type()); } 484 485 /* instantiate a class by a C-style array */ 486 template<class InstType, typename ArrType, std::size_t N, bool Reverse, typename... Ps> 487 struct h_instantiate_by_c_array; 488 489 template<class InstType, typename ArrType, std::size_t N, typename... Ps> 490 struct h_instantiate_by_c_array<InstType, ArrType, N, false, Ps...> 491 { 492 static InstType run(ArrType* arr, Ps... args) 493 { 494 return h_instantiate_by_c_array<InstType, ArrType, N - 1, false, Ps..., ArrType>::run(arr + 1, args..., arr[0]); 495 } 496 }; 497 498 template<class InstType, typename ArrType, std::size_t N, typename... Ps> 499 struct h_instantiate_by_c_array<InstType, ArrType, N, true, Ps...> 500 { 501 static InstType run(ArrType* arr, Ps... args) 502 { 503 return h_instantiate_by_c_array<InstType, ArrType, N - 1, false, ArrType, Ps...>::run(arr + 1, arr[0], args...); 504 } 505 }; 506 507 template<class InstType, typename ArrType, typename... Ps> 508 struct h_instantiate_by_c_array<InstType, ArrType, 0, false, Ps...> 509 { 510 static InstType run(ArrType* arr, Ps... args) 511 { 512 (void)arr; 513 return InstType(args...); 514 } 515 }; 516 517 template<class InstType, typename ArrType, typename... Ps> 518 struct h_instantiate_by_c_array<InstType, ArrType, 0, true, Ps...> 519 { 520 static InstType run(ArrType* arr, Ps... args) 521 { 522 (void)arr; 523 return InstType(args...); 524 } 525 }; 526 527 template<class InstType, typename ArrType, std::size_t N, bool Reverse = false> 528 InstType instantiate_by_c_array(ArrType* arr) 529 { 530 return h_instantiate_by_c_array<InstType, ArrType, N, Reverse>::run(arr); 531 } 532 533 } // end namespace internal 534 535 } // end namespace Eigen 536 537 #endif // EIGEN_CXX11META_H