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 // Emulate the cxx11 functionality that we need if the compiler doesn't support it.
17 // Visual studio 2015 doesn't advertise itself as cxx11 compliant, although it
18 // supports enough of the standard for our needs
19 #if __cplusplus > 199711L || EIGEN_COMP_MSVC >= 1900
20 
21 #include "CXX11Workarounds.h"
22 
23 namespace Eigen {
24 
25 namespace internal {
26 
27 /** \internal
28   * \file CXX11/util/CXX11Meta.h
29   * This file contains generic metaprogramming classes which are not specifically related to Eigen.
30   * This file expands upon Core/util/Meta.h and adds support for C++11 specific features.
31   */
32 
33 template<typename... tt>
34 struct type_list { constexpr static int count = sizeof...(tt); };
35 
36 template<typename t, typename... tt>
37 struct type_list<t, tt...> { constexpr static int count = sizeof...(tt) + 1; typedef t first_type; };
38 
39 template<typename T, T... nn>
40 struct numeric_list { constexpr static std::size_t count = sizeof...(nn); };
41 
42 template<typename T, T n, T... nn>
43 struct numeric_list<T, n, nn...> { constexpr static std::size_t count = sizeof...(nn) + 1; constexpr static T first_value = n; };
44 
45 /* numeric list constructors
46  *
47  * equivalencies:
48  *     constructor                                              result
49  *     typename gen_numeric_list<int, 5>::type                  numeric_list<int, 0,1,2,3,4>
50  *     typename gen_numeric_list_reversed<int, 5>::type         numeric_list<int, 4,3,2,1,0>
51  *     typename gen_numeric_list_swapped_pair<int, 5,1,2>::type numeric_list<int, 0,2,1,3,4>
52  *     typename gen_numeric_list_repeated<int, 0, 5>::type      numeric_list<int, 0,0,0,0,0>
53  */
54 
55 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...> {};
56 template<typename T, T start, T... ii>                    struct gen_numeric_list<T, 0, start, ii...> { typedef numeric_list<T, ii...> type; };
57 
58 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> {};
59 template<typename T, T start, T... ii>                    struct gen_numeric_list_reversed<T, 0, start, ii...> { typedef numeric_list<T, ii...> type; };
60 
61 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...> {};
62 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; };
63 
64 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...> {};
65 template<typename T, T V, T... nn>                struct gen_numeric_list_repeated<T, 0, V, nn...> { typedef numeric_list<T, nn...> type; };
66 
67 /* list manipulation: concatenate */
68 
69 template<class a, class b> struct concat;
70 
71 template<typename... as, typename... bs> struct concat<type_list<as...>,       type_list<bs...>>        { typedef type_list<as..., bs...> type; };
72 template<typename T, T... as, T... bs>   struct concat<numeric_list<T, as...>, numeric_list<T, bs...> > { typedef numeric_list<T, as..., bs...> type; };
73 
74 template<typename... p> struct mconcat;
75 template<typename a>                             struct mconcat<a>           { typedef a type; };
76 template<typename a, typename b>                 struct mconcat<a, b>        : concat<a, b> {};
77 template<typename a, typename b, typename... cs> struct mconcat<a, b, cs...> : concat<a, typename mconcat<b, cs...>::type> {};
78 
79 /* list manipulation: extract slices */
80 
81 template<int n, typename x> struct take;
82 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> {};
83 template<int n>                             struct take<n, type_list<>>         { typedef type_list<> type; };
84 template<typename a, typename... as>        struct take<0, type_list<a, as...>> { typedef type_list<> type; };
85 template<>                                  struct take<0, type_list<>>         { typedef type_list<> type; };
86 
87 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> {};
88 template<typename T, int n>               struct take<n, numeric_list<T>>           { typedef numeric_list<T> type; };
89 template<typename T, T a, T... as>        struct take<0, numeric_list<T, a, as...>> { typedef numeric_list<T> type; };
90 template<typename T>                      struct take<0, numeric_list<T>>           { typedef numeric_list<T> type; };
91 
92 template<typename T, int n, T... ii>      struct h_skip_helper_numeric;
93 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...> {};
94 template<typename T, T i, T... ii>        struct h_skip_helper_numeric<T, 0, i, ii...> { typedef numeric_list<T, i, ii...> type; };
95 template<typename T, int n>               struct h_skip_helper_numeric<T, n>           { typedef numeric_list<T> type; };
96 template<typename T>                      struct h_skip_helper_numeric<T, 0>           { typedef numeric_list<T> type; };
97 
98 template<int n, typename... tt>             struct h_skip_helper_type;
99 template<int n, typename t, typename... tt> struct h_skip_helper_type<n, t, tt...> : h_skip_helper_type<n-1, tt...> {};
100 template<typename t, typename... tt>        struct h_skip_helper_type<0, t, tt...> { typedef type_list<t, tt...> type; };
101 template<int n>                             struct h_skip_helper_type<n>           { typedef type_list<> type; };
102 template<>                                  struct h_skip_helper_type<0>           { typedef type_list<> type; };
103 
104 template<int n>
105 struct h_skip {
106   template<typename T, T... ii>
107   constexpr static 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(); }
108   template<typename... tt>
109   constexpr static inline typename h_skip_helper_type<n, tt...>::type helper(type_list<tt...>) { return typename h_skip_helper_type<n, tt...>::type(); }
110 };
111 
112 template<int n, typename a> struct skip { typedef decltype(h_skip<n>::helper(a())) type; };
113 
114 template<int start, int count, typename a> struct slice : take<count, typename skip<start, a>::type> {};
115 
116 /* list manipulation: retrieve single element from list */
117 
118 template<int n, typename x> struct get;
119 
120 template<int n, typename a, typename... as>               struct get<n, type_list<a, as...>>   : get<n-1, type_list<as...>> {};
121 template<typename a, typename... as>                      struct get<0, type_list<a, as...>>   { typedef a type; };
122 
123 template<typename T, int n, T a, T... as>                        struct get<n, numeric_list<T, a, as...>>   : get<n-1, numeric_list<T, as...>> {};
124 template<typename T, T a, T... as>                               struct get<0, numeric_list<T, a, as...>>   { constexpr static T value = a; };
125 
126 /* always get type, regardless of dummy; good for parameter pack expansion */
127 
128 template<typename T, T dummy, typename t> struct id_numeric  { typedef t type; };
129 template<typename dummy, typename t>      struct id_type     { typedef t type; };
130 
131 /* equality checking, flagged version */
132 
133 template<typename a, typename b> struct is_same_gf : is_same<a, b> { constexpr static int global_flags = 0; };
134 
135 /* apply_op to list */
136 
137 template<
138   bool from_left, // false
139   template<typename, typename> class op,
140   typename additional_param,
141   typename... values
142 >
143 struct h_apply_op_helper                                        { typedef type_list<typename op<values, additional_param>::type...> type; };
144 template<
145   template<typename, typename> class op,
146   typename additional_param,
147   typename... values
148 >
149 struct h_apply_op_helper<true, op, additional_param, values...> { typedef type_list<typename op<additional_param, values>::type...> type; };
150 
151 template<
152   bool from_left,
153   template<typename, typename> class op,
154   typename additional_param
155 >
156 struct h_apply_op
157 {
158   template<typename... values>
159   constexpr static typename h_apply_op_helper<from_left, op, additional_param, values...>::type helper(type_list<values...>)
160   { return typename h_apply_op_helper<from_left, op, additional_param, values...>::type(); }
161 };
162 
163 template<
164   template<typename, typename> class op,
165   typename additional_param,
166   typename a
167 >
168 struct apply_op_from_left { typedef decltype(h_apply_op<true, op, additional_param>::helper(a())) type; };
169 
170 template<
171   template<typename, typename> class op,
172   typename additional_param,
173   typename a
174 >
175 struct apply_op_from_right { typedef decltype(h_apply_op<false, op, additional_param>::helper(a())) type; };
176 
177 /* see if an element is in a list */
178 
179 template<
180   template<typename, typename> class test,
181   typename check_against,
182   typename h_list,
183   bool last_check_positive = false
184 >
185 struct contained_in_list;
186 
187 template<
188   template<typename, typename> class test,
189   typename check_against,
190   typename h_list
191 >
192 struct contained_in_list<test, check_against, h_list, true>
193 {
194   constexpr static bool value = true;
195 };
196 
197 template<
198   template<typename, typename> class test,
199   typename check_against,
200   typename a,
201   typename... as
202 >
203 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> {};
204 
205 template<
206   template<typename, typename> class test,
207   typename check_against
208   EIGEN_TPL_PP_SPEC_HACK_DEFC(typename, empty)
209 >
210 struct contained_in_list<test, check_against, type_list<EIGEN_TPL_PP_SPEC_HACK_USE(empty)>, false> { constexpr static bool value = false; };
211 
212 /* see if an element is in a list and check for global flags */
213 
214 template<
215   template<typename, typename> class test,
216   typename check_against,
217   typename h_list,
218   int default_flags = 0,
219   bool last_check_positive = false,
220   int last_check_flags = default_flags
221 >
222 struct contained_in_list_gf;
223 
224 template<
225   template<typename, typename> class test,
226   typename check_against,
227   typename h_list,
228   int default_flags,
229   int last_check_flags
230 >
231 struct contained_in_list_gf<test, check_against, h_list, default_flags, true, last_check_flags>
232 {
233   constexpr static bool value = true;
234   constexpr static int global_flags = last_check_flags;
235 };
236 
237 template<
238   template<typename, typename> class test,
239   typename check_against,
240   typename a,
241   typename... as,
242   int default_flags,
243   int last_check_flags
244 >
245 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> {};
246 
247 template<
248   template<typename, typename> class test,
249   typename check_against
250   EIGEN_TPL_PP_SPEC_HACK_DEFC(typename, empty),
251   int default_flags,
252   int last_check_flags
253 >
254 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; };
255 
256 /* generic reductions */
257 
258 template<
259   typename Reducer,
260   typename... Ts
261 > struct reduce;
262 
263 template<
264   typename Reducer
265 > struct reduce<Reducer>
266 {
267   constexpr static inline int run() { return Reducer::Identity; }
268 };
269 
270 template<
271   typename Reducer,
272   typename A
273 > struct reduce<Reducer, A>
274 {
275   constexpr static inline A run(A a) { return a; }
276 };
277 
278 template<
279   typename Reducer,
280   typename A,
281   typename... Ts
282 > struct reduce<Reducer, A, Ts...>
283 {
284   constexpr static inline auto run(A a, Ts... ts) -> decltype(Reducer::run(a, reduce<Reducer, Ts...>::run(ts...))) {
285     return Reducer::run(a, reduce<Reducer, Ts...>::run(ts...));
286   }
287 };
288 
289 /* generic binary operations */
290 
291 struct sum_op           {
292   template<typename A, typename B> EIGEN_DEVICE_FUNC constexpr static inline auto run(A a, B b) -> decltype(a + b)   { return a + b;   }
293   static constexpr int Identity = 0;
294 };
295 struct product_op       {
296   template<typename A, typename B> EIGEN_DEVICE_FUNC constexpr static inline auto run(A a, B b) -> decltype(a * b)   { return a * b;   }
297   static constexpr int Identity = 1;
298 };
299 
300 struct logical_and_op   { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a && b)  { return a && b;  } };
301 struct logical_or_op    { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a || b)  { return a || b;  } };
302 
303 struct equal_op         { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a == b)  { return a == b;  } };
304 struct not_equal_op     { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a != b)  { return a != b;  } };
305 struct lesser_op        { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a < b)   { return a < b;   } };
306 struct lesser_equal_op  { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a <= b)  { return a <= b;  } };
307 struct greater_op       { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a > b)   { return a > b;   } };
308 struct greater_equal_op { template<typename A, typename B> constexpr static inline auto run(A a, B b) -> decltype(a >= b)  { return a >= b;  } };
309 
310 /* generic unary operations */
311 
312 struct not_op                { template<typename A> constexpr static inline auto run(A a) -> decltype(!a)      { return !a;      } };
313 struct negation_op           { template<typename A> constexpr static inline auto run(A a) -> decltype(-a)      { return -a;      } };
314 struct greater_equal_zero_op { template<typename A> constexpr static inline auto run(A a) -> decltype(a >= 0)  { return a >= 0;  } };
315 
316 
317 /* reductions for lists */
318 
319 // using auto -> return value spec makes ICC 13.0 and 13.1 crash here, so we have to hack it
320 // together in front... (13.0 doesn't work with array_prod/array_reduce/... anyway, but 13.1
321 // does...
322 template<typename... Ts>
323 constexpr inline decltype(reduce<product_op, Ts...>::run((*((Ts*)0))...)) arg_prod(Ts... ts)
324 {
325   return reduce<product_op, Ts...>::run(ts...);
326 }
327 
328 template<typename... Ts>
329 constexpr inline decltype(reduce<sum_op, Ts...>::run((*((Ts*)0))...)) arg_sum(Ts... ts)
330 {
331   return reduce<sum_op, Ts...>::run(ts...);
332 }
333 
334 /* reverse arrays */
335 
336 template<typename Array, int... n>
337 constexpr inline Array h_array_reverse(Array arr, numeric_list<int, n...>)
338 {
339   return {{array_get<sizeof...(n) - n - 1>(arr)...}};
340 }
341 
342 template<typename T, std::size_t N>
343 constexpr inline array<T, N> array_reverse(array<T, N> arr)
344 {
345   return h_array_reverse(arr, typename gen_numeric_list<int, N>::type());
346 }
347 
348 
349 /* generic array reductions */
350 
351 // can't reuse standard reduce() interface above because Intel's Compiler
352 // *really* doesn't like it, so we just reimplement the stuff
353 // (start from N - 1 and work down to 0 because specialization for
354 // n == N - 1 also doesn't work in Intel's compiler, so it goes into
355 // an infinite loop)
356 template<typename Reducer, typename T, std::size_t N, std::size_t n = N - 1>
357 struct h_array_reduce {
358   EIGEN_DEVICE_FUNC constexpr static 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)))
359   {
360     return Reducer::run(h_array_reduce<Reducer, T, N, n - 1>::run(arr, identity), array_get<n>(arr));
361   }
362 };
363 
364 template<typename Reducer, typename T, std::size_t N>
365 struct h_array_reduce<Reducer, T, N, 0>
366 {
367   EIGEN_DEVICE_FUNC constexpr static inline T run(const array<T, N>& arr, T)
368   {
369     return array_get<0>(arr);
370   }
371 };
372 
373 template<typename Reducer, typename T>
374 struct h_array_reduce<Reducer, T, 0>
375 {
376   EIGEN_DEVICE_FUNC constexpr static inline T run(const array<T, 0>&, T identity)
377   {
378     return identity;
379   }
380 };
381 
382 template<typename Reducer, typename T, std::size_t N>
383 EIGEN_DEVICE_FUNC constexpr inline auto array_reduce(const array<T, N>& arr, T identity) -> decltype(h_array_reduce<Reducer, T, N>::run(arr, identity))
384 {
385   return h_array_reduce<Reducer, T, N>::run(arr, identity);
386 }
387 
388 /* standard array reductions */
389 
390 template<typename T, std::size_t N>
391 EIGEN_DEVICE_FUNC constexpr inline auto array_sum(const array<T, N>& arr) -> decltype(array_reduce<sum_op, T, N>(arr, static_cast<T>(0)))
392 {
393   return array_reduce<sum_op, T, N>(arr, static_cast<T>(0));
394 }
395 
396 template<typename T, std::size_t N>
397 EIGEN_DEVICE_FUNC constexpr inline auto array_prod(const array<T, N>& arr) -> decltype(array_reduce<product_op, T, N>(arr, static_cast<T>(1)))
398 {
399   return array_reduce<product_op, T, N>(arr, static_cast<T>(1));
400 }
401 
402 template<typename t>
403 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE t array_prod(const std::vector<t>& a) {
404   eigen_assert(a.size() > 0);
405   t prod = 1;
406   for (size_t i = 0; i < a.size(); ++i) { prod *= a[i]; }
407   return prod;
408 }
409 
410 /* zip an array */
411 
412 template<typename Op, typename A, typename B, std::size_t N, int... n>
413 constexpr inline array<decltype(Op::run(A(), B())),N> h_array_zip(array<A, N> a, array<B, N> b, numeric_list<int, n...>)
414 {
415   return array<decltype(Op::run(A(), B())),N>{{ Op::run(array_get<n>(a), array_get<n>(b))... }};
416 }
417 
418 template<typename Op, typename A, typename B, std::size_t N>
419 constexpr inline array<decltype(Op::run(A(), B())),N> array_zip(array<A, N> a, array<B, N> b)
420 {
421   return h_array_zip<Op>(a, b, typename gen_numeric_list<int, N>::type());
422 }
423 
424 /* zip an array and reduce the result */
425 
426 template<typename Reducer, typename Op, typename A, typename B, std::size_t N, int... n>
427 constexpr 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))...))
428 {
429   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))...);
430 }
431 
432 template<typename Reducer, typename Op, typename A, typename B, std::size_t N>
433 constexpr 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()))
434 {
435   return h_array_zip_and_reduce<Reducer, Op, A, B, N>(a, b, typename gen_numeric_list<int, N>::type());
436 }
437 
438 /* apply stuff to an array */
439 
440 template<typename Op, typename A, std::size_t N, int... n>
441 constexpr inline array<decltype(Op::run(A())),N> h_array_apply(array<A, N> a, numeric_list<int, n...>)
442 {
443   return array<decltype(Op::run(A())),N>{{ Op::run(array_get<n>(a))... }};
444 }
445 
446 template<typename Op, typename A, std::size_t N>
447 constexpr inline array<decltype(Op::run(A())),N> array_apply(array<A, N> a)
448 {
449   return h_array_apply<Op>(a, typename gen_numeric_list<int, N>::type());
450 }
451 
452 /* apply stuff to an array and reduce */
453 
454 template<typename Reducer, typename Op, typename A, std::size_t N, int... n>
455 constexpr 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))...))
456 {
457   return reduce<Reducer, typename id_numeric<int,n,decltype(Op::run(A()))>::type...>::run(Op::run(array_get<n>(arr))...);
458 }
459 
460 template<typename Reducer, typename Op, typename A, std::size_t N>
461 constexpr 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()))
462 {
463   return h_array_apply_and_reduce<Reducer, Op, A, N>(a, typename gen_numeric_list<int, N>::type());
464 }
465 
466 /* repeat a value n times (and make an array out of it
467  * usage:
468  *   array<int, 16> = repeat<16>(42);
469  */
470 
471 template<int n>
472 struct h_repeat
473 {
474   template<typename t, int... ii>
475   constexpr static inline array<t, n> run(t v, numeric_list<int, ii...>)
476   {
477     return {{ typename id_numeric<int, ii, t>::type(v)... }};
478   }
479 };
480 
481 template<int n, typename t>
482 constexpr array<t, n> repeat(t v) { return h_repeat<n>::run(v, typename gen_numeric_list<int, n>::type()); }
483 
484 /* instantiate a class by a C-style array */
485 template<class InstType, typename ArrType, std::size_t N, bool Reverse, typename... Ps>
486 struct h_instantiate_by_c_array;
487 
488 template<class InstType, typename ArrType, std::size_t N, typename... Ps>
489 struct h_instantiate_by_c_array<InstType, ArrType, N, false, Ps...>
490 {
491   static InstType run(ArrType* arr, Ps... args)
492   {
493     return h_instantiate_by_c_array<InstType, ArrType, N - 1, false, Ps..., ArrType>::run(arr + 1, args..., arr[0]);
494   }
495 };
496 
497 template<class InstType, typename ArrType, std::size_t N, typename... Ps>
498 struct h_instantiate_by_c_array<InstType, ArrType, N, true, Ps...>
499 {
500   static InstType run(ArrType* arr, Ps... args)
501   {
502     return h_instantiate_by_c_array<InstType, ArrType, N - 1, false, ArrType, Ps...>::run(arr + 1, arr[0], args...);
503   }
504 };
505 
506 template<class InstType, typename ArrType, typename... Ps>
507 struct h_instantiate_by_c_array<InstType, ArrType, 0, false, Ps...>
508 {
509   static InstType run(ArrType* arr, Ps... args)
510   {
511     (void)arr;
512     return InstType(args...);
513   }
514 };
515 
516 template<class InstType, typename ArrType, typename... Ps>
517 struct h_instantiate_by_c_array<InstType, ArrType, 0, true, Ps...>
518 {
519   static InstType run(ArrType* arr, Ps... args)
520   {
521     (void)arr;
522     return InstType(args...);
523   }
524 };
525 
526 template<class InstType, typename ArrType, std::size_t N, bool Reverse = false>
527 InstType instantiate_by_c_array(ArrType* arr)
528 {
529   return h_instantiate_by_c_array<InstType, ArrType, N, Reverse>::run(arr);
530 }
531 
532 } // end namespace internal
533 
534 } // end namespace Eigen
535 
536 #else // Non C++11, fallback to emulation mode
537 
538 #include "EmulateCXX11Meta.h"
539 
540 #endif
541 
542 #endif // EIGEN_CXX11META_H
543