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1 // This file is part of Eigen, a lightweight C++ template library
2 // for linear algebra.
3 //
4 // Copyright (C) 2009 Gael Guennebaud <gael.guennebaud@inria.fr>
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_AUTODIFF_SCALAR_H
11 #define EIGEN_AUTODIFF_SCALAR_H
12 
13 namespace Eigen {
14 
15 namespace internal {
16 
17 template<typename A, typename B>
18 struct make_coherent_impl {
runmake_coherent_impl19   static void run(A&, B&) {}
20 };
21 
22 // resize a to match b is a.size()==0, and conversely.
23 template<typename A, typename B>
make_coherent(const A & a,const B & b)24 void make_coherent(const A& a, const B&b)
25 {
26   make_coherent_impl<A,B>::run(a.const_cast_derived(), b.const_cast_derived());
27 }
28 
29 template<typename _DerType, bool Enable> struct auto_diff_special_op;
30 
31 } // end namespace internal
32 
33 template<typename _DerType> class AutoDiffScalar;
34 
35 template<typename NewDerType>
MakeAutoDiffScalar(const typename NewDerType::Scalar & value,const NewDerType & der)36 inline AutoDiffScalar<NewDerType> MakeAutoDiffScalar(const typename NewDerType::Scalar& value, const NewDerType &der) {
37   return AutoDiffScalar<NewDerType>(value,der);
38 }
39 
40 /** \class AutoDiffScalar
41   * \brief A scalar type replacement with automatic differentation capability
42   *
43   * \param _DerType the vector type used to store/represent the derivatives. The base scalar type
44   *                 as well as the number of derivatives to compute are determined from this type.
45   *                 Typical choices include, e.g., \c Vector4f for 4 derivatives, or \c VectorXf
46   *                 if the number of derivatives is not known at compile time, and/or, the number
47   *                 of derivatives is large.
48   *                 Note that _DerType can also be a reference (e.g., \c VectorXf&) to wrap a
49   *                 existing vector into an AutoDiffScalar.
50   *                 Finally, _DerType can also be any Eigen compatible expression.
51   *
52   * This class represents a scalar value while tracking its respective derivatives using Eigen's expression
53   * template mechanism.
54   *
55   * It supports the following list of global math function:
56   *  - std::abs, std::sqrt, std::pow, std::exp, std::log, std::sin, std::cos,
57   *  - internal::abs, internal::sqrt, numext::pow, internal::exp, internal::log, internal::sin, internal::cos,
58   *  - internal::conj, internal::real, internal::imag, numext::abs2.
59   *
60   * AutoDiffScalar can be used as the scalar type of an Eigen::Matrix object. However,
61   * in that case, the expression template mechanism only occurs at the top Matrix level,
62   * while derivatives are computed right away.
63   *
64   */
65 
66 template<typename _DerType>
67 class AutoDiffScalar
68   : public internal::auto_diff_special_op
69             <_DerType, !internal::is_same<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar,
70                                           typename NumTraits<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar>::Real>::value>
71 {
72   public:
73     typedef internal::auto_diff_special_op
74             <_DerType, !internal::is_same<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar,
75                        typename NumTraits<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar>::Real>::value> Base;
76     typedef typename internal::remove_all<_DerType>::type DerType;
77     typedef typename internal::traits<DerType>::Scalar Scalar;
78     typedef typename NumTraits<Scalar>::Real Real;
79 
80     using Base::operator+;
81     using Base::operator*;
82 
83     /** Default constructor without any initialization. */
AutoDiffScalar()84     AutoDiffScalar() {}
85 
86     /** Constructs an active scalar from its \a value,
87         and initializes the \a nbDer derivatives such that it corresponds to the \a derNumber -th variable */
AutoDiffScalar(const Scalar & value,int nbDer,int derNumber)88     AutoDiffScalar(const Scalar& value, int nbDer, int derNumber)
89       : m_value(value), m_derivatives(DerType::Zero(nbDer))
90     {
91       m_derivatives.coeffRef(derNumber) = Scalar(1);
92     }
93 
94     /** Conversion from a scalar constant to an active scalar.
95       * The derivatives are set to zero. */
AutoDiffScalar(const Real & value)96     /*explicit*/ AutoDiffScalar(const Real& value)
97       : m_value(value)
98     {
99       if(m_derivatives.size()>0)
100         m_derivatives.setZero();
101     }
102 
103     /** Constructs an active scalar from its \a value and derivatives \a der */
AutoDiffScalar(const Scalar & value,const DerType & der)104     AutoDiffScalar(const Scalar& value, const DerType& der)
105       : m_value(value), m_derivatives(der)
106     {}
107 
108     template<typename OtherDerType>
109     AutoDiffScalar(const AutoDiffScalar<OtherDerType>& other
110 #ifndef EIGEN_PARSED_BY_DOXYGEN
111     , typename internal::enable_if<
112             internal::is_same<Scalar, typename internal::traits<typename internal::remove_all<OtherDerType>::type>::Scalar>::value
113         &&  internal::is_convertible<OtherDerType,DerType>::value , void*>::type = 0
114 #endif
115     )
116       : m_value(other.value()), m_derivatives(other.derivatives())
117     {}
118 
119     friend  std::ostream & operator << (std::ostream & s, const AutoDiffScalar& a)
120     {
121       return s << a.value();
122     }
123 
AutoDiffScalar(const AutoDiffScalar & other)124     AutoDiffScalar(const AutoDiffScalar& other)
125       : m_value(other.value()), m_derivatives(other.derivatives())
126     {}
127 
128     template<typename OtherDerType>
129     inline AutoDiffScalar& operator=(const AutoDiffScalar<OtherDerType>& other)
130     {
131       m_value = other.value();
132       m_derivatives = other.derivatives();
133       return *this;
134     }
135 
136     inline AutoDiffScalar& operator=(const AutoDiffScalar& other)
137     {
138       m_value = other.value();
139       m_derivatives = other.derivatives();
140       return *this;
141     }
142 
143     inline AutoDiffScalar& operator=(const Scalar& other)
144     {
145       m_value = other;
146       if(m_derivatives.size()>0)
147         m_derivatives.setZero();
148       return *this;
149     }
150 
151 //     inline operator const Scalar& () const { return m_value; }
152 //     inline operator Scalar& () { return m_value; }
153 
value()154     inline const Scalar& value() const { return m_value; }
value()155     inline Scalar& value() { return m_value; }
156 
derivatives()157     inline const DerType& derivatives() const { return m_derivatives; }
derivatives()158     inline DerType& derivatives() { return m_derivatives; }
159 
160     inline bool operator< (const Scalar& other) const  { return m_value <  other; }
161     inline bool operator<=(const Scalar& other) const  { return m_value <= other; }
162     inline bool operator> (const Scalar& other) const  { return m_value >  other; }
163     inline bool operator>=(const Scalar& other) const  { return m_value >= other; }
164     inline bool operator==(const Scalar& other) const  { return m_value == other; }
165     inline bool operator!=(const Scalar& other) const  { return m_value != other; }
166 
167     friend inline bool operator< (const Scalar& a, const AutoDiffScalar& b) { return a <  b.value(); }
168     friend inline bool operator<=(const Scalar& a, const AutoDiffScalar& b) { return a <= b.value(); }
169     friend inline bool operator> (const Scalar& a, const AutoDiffScalar& b) { return a >  b.value(); }
170     friend inline bool operator>=(const Scalar& a, const AutoDiffScalar& b) { return a >= b.value(); }
171     friend inline bool operator==(const Scalar& a, const AutoDiffScalar& b) { return a == b.value(); }
172     friend inline bool operator!=(const Scalar& a, const AutoDiffScalar& b) { return a != b.value(); }
173 
174     template<typename OtherDerType> inline bool operator< (const AutoDiffScalar<OtherDerType>& b) const  { return m_value <  b.value(); }
175     template<typename OtherDerType> inline bool operator<=(const AutoDiffScalar<OtherDerType>& b) const  { return m_value <= b.value(); }
176     template<typename OtherDerType> inline bool operator> (const AutoDiffScalar<OtherDerType>& b) const  { return m_value >  b.value(); }
177     template<typename OtherDerType> inline bool operator>=(const AutoDiffScalar<OtherDerType>& b) const  { return m_value >= b.value(); }
178     template<typename OtherDerType> inline bool operator==(const AutoDiffScalar<OtherDerType>& b) const  { return m_value == b.value(); }
179     template<typename OtherDerType> inline bool operator!=(const AutoDiffScalar<OtherDerType>& b) const  { return m_value != b.value(); }
180 
181     inline const AutoDiffScalar<DerType&> operator+(const Scalar& other) const
182     {
183       return AutoDiffScalar<DerType&>(m_value + other, m_derivatives);
184     }
185 
186     friend inline const AutoDiffScalar<DerType&> operator+(const Scalar& a, const AutoDiffScalar& b)
187     {
188       return AutoDiffScalar<DerType&>(a + b.value(), b.derivatives());
189     }
190 
191 //     inline const AutoDiffScalar<DerType&> operator+(const Real& other) const
192 //     {
193 //       return AutoDiffScalar<DerType&>(m_value + other, m_derivatives);
194 //     }
195 
196 //     friend inline const AutoDiffScalar<DerType&> operator+(const Real& a, const AutoDiffScalar& b)
197 //     {
198 //       return AutoDiffScalar<DerType&>(a + b.value(), b.derivatives());
199 //     }
200 
201     inline AutoDiffScalar& operator+=(const Scalar& other)
202     {
203       value() += other;
204       return *this;
205     }
206 
207     template<typename OtherDerType>
208     inline const AutoDiffScalar<CwiseBinaryOp<internal::scalar_sum_op<Scalar>,const DerType,const typename internal::remove_all<OtherDerType>::type> >
209     operator+(const AutoDiffScalar<OtherDerType>& other) const
210     {
211       internal::make_coherent(m_derivatives, other.derivatives());
212       return AutoDiffScalar<CwiseBinaryOp<internal::scalar_sum_op<Scalar>,const DerType,const typename internal::remove_all<OtherDerType>::type> >(
213         m_value + other.value(),
214         m_derivatives + other.derivatives());
215     }
216 
217     template<typename OtherDerType>
218     inline AutoDiffScalar&
219     operator+=(const AutoDiffScalar<OtherDerType>& other)
220     {
221       (*this) = (*this) + other;
222       return *this;
223     }
224 
225     inline const AutoDiffScalar<DerType&> operator-(const Scalar& b) const
226     {
227       return AutoDiffScalar<DerType&>(m_value - b, m_derivatives);
228     }
229 
230     friend inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >
231     operator-(const Scalar& a, const AutoDiffScalar& b)
232     {
233       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >
234             (a - b.value(), -b.derivatives());
235     }
236 
237     inline AutoDiffScalar& operator-=(const Scalar& other)
238     {
239       value() -= other;
240       return *this;
241     }
242 
243     template<typename OtherDerType>
244     inline const AutoDiffScalar<CwiseBinaryOp<internal::scalar_difference_op<Scalar>, const DerType,const typename internal::remove_all<OtherDerType>::type> >
245     operator-(const AutoDiffScalar<OtherDerType>& other) const
246     {
247       internal::make_coherent(m_derivatives, other.derivatives());
248       return AutoDiffScalar<CwiseBinaryOp<internal::scalar_difference_op<Scalar>, const DerType,const typename internal::remove_all<OtherDerType>::type> >(
249         m_value - other.value(),
250         m_derivatives - other.derivatives());
251     }
252 
253     template<typename OtherDerType>
254     inline AutoDiffScalar&
255     operator-=(const AutoDiffScalar<OtherDerType>& other)
256     {
257       *this = *this - other;
258       return *this;
259     }
260 
261     inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >
262     operator-() const
263     {
264       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >(
265         -m_value,
266         -m_derivatives);
267     }
268 
269     inline const AutoDiffScalar<EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(DerType,Scalar,product) >
270     operator*(const Scalar& other) const
271     {
272       return MakeAutoDiffScalar(m_value * other, m_derivatives * other);
273     }
274 
275     friend inline const AutoDiffScalar<EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(DerType,Scalar,product) >
276     operator*(const Scalar& other, const AutoDiffScalar& a)
277     {
278       return MakeAutoDiffScalar(a.value() * other, a.derivatives() * other);
279     }
280 
281 //     inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
282 //     operator*(const Real& other) const
283 //     {
284 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
285 //         m_value * other,
286 //         (m_derivatives * other));
287 //     }
288 //
289 //     friend inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
290 //     operator*(const Real& other, const AutoDiffScalar& a)
291 //     {
292 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
293 //         a.value() * other,
294 //         a.derivatives() * other);
295 //     }
296 
297     inline const AutoDiffScalar<EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(DerType,Scalar,product) >
298     operator/(const Scalar& other) const
299     {
300       return MakeAutoDiffScalar(m_value / other, (m_derivatives * (Scalar(1)/other)));
301     }
302 
303     friend inline const AutoDiffScalar<EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(DerType,Scalar,product) >
304     operator/(const Scalar& other, const AutoDiffScalar& a)
305     {
306       return MakeAutoDiffScalar(other / a.value(), a.derivatives() * (Scalar(-other) / (a.value()*a.value())));
307     }
308 
309 //     inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
310 //     operator/(const Real& other) const
311 //     {
312 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
313 //         m_value / other,
314 //         (m_derivatives * (Real(1)/other)));
315 //     }
316 //
317 //     friend inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
318 //     operator/(const Real& other, const AutoDiffScalar& a)
319 //     {
320 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
321 //         other / a.value(),
322 //         a.derivatives() * (-Real(1)/other));
323 //     }
324 
325     template<typename OtherDerType>
326     inline const AutoDiffScalar<EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(
327         CwiseBinaryOp<internal::scalar_difference_op<Scalar> EIGEN_COMMA
328           const EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(DerType,Scalar,product) EIGEN_COMMA
329           const EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(typename internal::remove_all<OtherDerType>::type,Scalar,product) >,Scalar,product) >
330     operator/(const AutoDiffScalar<OtherDerType>& other) const
331     {
332       internal::make_coherent(m_derivatives, other.derivatives());
333       return MakeAutoDiffScalar(
334         m_value / other.value(),
335           ((m_derivatives * other.value()) - (other.derivatives() * m_value))
336         * (Scalar(1)/(other.value()*other.value())));
337     }
338 
339     template<typename OtherDerType>
340     inline const AutoDiffScalar<CwiseBinaryOp<internal::scalar_sum_op<Scalar>,
341         const EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(DerType,Scalar,product),
342         const EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(typename internal::remove_all<OtherDerType>::type,Scalar,product) > >
343     operator*(const AutoDiffScalar<OtherDerType>& other) const
344     {
345       internal::make_coherent(m_derivatives, other.derivatives());
346       return MakeAutoDiffScalar(
347         m_value * other.value(),
348         (m_derivatives * other.value()) + (other.derivatives() * m_value));
349     }
350 
351     inline AutoDiffScalar& operator*=(const Scalar& other)
352     {
353       *this = *this * other;
354       return *this;
355     }
356 
357     template<typename OtherDerType>
358     inline AutoDiffScalar& operator*=(const AutoDiffScalar<OtherDerType>& other)
359     {
360       *this = *this * other;
361       return *this;
362     }
363 
364     inline AutoDiffScalar& operator/=(const Scalar& other)
365     {
366       *this = *this / other;
367       return *this;
368     }
369 
370     template<typename OtherDerType>
371     inline AutoDiffScalar& operator/=(const AutoDiffScalar<OtherDerType>& other)
372     {
373       *this = *this / other;
374       return *this;
375     }
376 
377   protected:
378     Scalar m_value;
379     DerType m_derivatives;
380 
381 };
382 
383 namespace internal {
384 
385 template<typename _DerType>
386 struct auto_diff_special_op<_DerType, true>
387 //   : auto_diff_scalar_op<_DerType, typename NumTraits<Scalar>::Real,
388 //                            is_same<Scalar,typename NumTraits<Scalar>::Real>::value>
389 {
390   typedef typename remove_all<_DerType>::type DerType;
391   typedef typename traits<DerType>::Scalar Scalar;
392   typedef typename NumTraits<Scalar>::Real Real;
393 
394 //   typedef auto_diff_scalar_op<_DerType, typename NumTraits<Scalar>::Real,
395 //                            is_same<Scalar,typename NumTraits<Scalar>::Real>::value> Base;
396 
397 //   using Base::operator+;
398 //   using Base::operator+=;
399 //   using Base::operator-;
400 //   using Base::operator-=;
401 //   using Base::operator*;
402 //   using Base::operator*=;
403 
404   const AutoDiffScalar<_DerType>& derived() const { return *static_cast<const AutoDiffScalar<_DerType>*>(this); }
405   AutoDiffScalar<_DerType>& derived() { return *static_cast<AutoDiffScalar<_DerType>*>(this); }
406 
407 
408   inline const AutoDiffScalar<DerType&> operator+(const Real& other) const
409   {
410     return AutoDiffScalar<DerType&>(derived().value() + other, derived().derivatives());
411   }
412 
413   friend inline const AutoDiffScalar<DerType&> operator+(const Real& a, const AutoDiffScalar<_DerType>& b)
414   {
415     return AutoDiffScalar<DerType&>(a + b.value(), b.derivatives());
416   }
417 
418   inline AutoDiffScalar<_DerType>& operator+=(const Real& other)
419   {
420     derived().value() += other;
421     return derived();
422   }
423 
424 
425   inline const AutoDiffScalar<typename CwiseUnaryOp<bind2nd_op<scalar_product_op<Scalar,Real> >, DerType>::Type >
426   operator*(const Real& other) const
427   {
428     return AutoDiffScalar<typename CwiseUnaryOp<bind2nd_op<scalar_product_op<Scalar,Real> >, DerType>::Type >(
429       derived().value() * other,
430       derived().derivatives() * other);
431   }
432 
433   friend inline const AutoDiffScalar<typename CwiseUnaryOp<bind1st_op<scalar_product_op<Real,Scalar> >, DerType>::Type >
434   operator*(const Real& other, const AutoDiffScalar<_DerType>& a)
435   {
436     return AutoDiffScalar<typename CwiseUnaryOp<bind1st_op<scalar_product_op<Real,Scalar> >, DerType>::Type >(
437       a.value() * other,
438       a.derivatives() * other);
439   }
440 
441   inline AutoDiffScalar<_DerType>& operator*=(const Scalar& other)
442   {
443     *this = *this * other;
444     return derived();
445   }
446 };
447 
448 template<typename _DerType>
449 struct auto_diff_special_op<_DerType, false>
450 {
451   void operator*() const;
452   void operator-() const;
453   void operator+() const;
454 };
455 
456 template<typename A_Scalar, int A_Rows, int A_Cols, int A_Options, int A_MaxRows, int A_MaxCols, typename B>
457 struct make_coherent_impl<Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols>, B> {
458   typedef Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> A;
459   static void run(A& a, B& b) {
460     if((A_Rows==Dynamic || A_Cols==Dynamic) && (a.size()==0))
461     {
462       a.resize(b.size());
463       a.setZero();
464     }
465   }
466 };
467 
468 template<typename A, typename B_Scalar, int B_Rows, int B_Cols, int B_Options, int B_MaxRows, int B_MaxCols>
469 struct make_coherent_impl<A, Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> > {
470   typedef Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> B;
471   static void run(A& a, B& b) {
472     if((B_Rows==Dynamic || B_Cols==Dynamic) && (b.size()==0))
473     {
474       b.resize(a.size());
475       b.setZero();
476     }
477   }
478 };
479 
480 template<typename A_Scalar, int A_Rows, int A_Cols, int A_Options, int A_MaxRows, int A_MaxCols,
481          typename B_Scalar, int B_Rows, int B_Cols, int B_Options, int B_MaxRows, int B_MaxCols>
482 struct make_coherent_impl<Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols>,
483                              Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> > {
484   typedef Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> A;
485   typedef Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> B;
486   static void run(A& a, B& b) {
487     if((A_Rows==Dynamic || A_Cols==Dynamic) && (a.size()==0))
488     {
489       a.resize(b.size());
490       a.setZero();
491     }
492     else if((B_Rows==Dynamic || B_Cols==Dynamic) && (b.size()==0))
493     {
494       b.resize(a.size());
495       b.setZero();
496     }
497   }
498 };
499 
500 } // end namespace internal
501 
502 template<typename DerType, typename BinOp>
503 struct ScalarBinaryOpTraits<AutoDiffScalar<DerType>,typename DerType::Scalar,BinOp>
504 {
505   typedef AutoDiffScalar<DerType> ReturnType;
506 };
507 
508 template<typename DerType, typename BinOp>
509 struct ScalarBinaryOpTraits<typename DerType::Scalar,AutoDiffScalar<DerType>, BinOp>
510 {
511   typedef AutoDiffScalar<DerType> ReturnType;
512 };
513 
514 
515 // The following is an attempt to let Eigen's known about expression template, but that's more tricky!
516 
517 // template<typename DerType, typename BinOp>
518 // struct ScalarBinaryOpTraits<AutoDiffScalar<DerType>,AutoDiffScalar<DerType>, BinOp>
519 // {
520 //   enum { Defined = 1 };
521 //   typedef AutoDiffScalar<typename DerType::PlainObject> ReturnType;
522 // };
523 //
524 // template<typename DerType1,typename DerType2, typename BinOp>
525 // struct ScalarBinaryOpTraits<AutoDiffScalar<DerType1>,AutoDiffScalar<DerType2>, BinOp>
526 // {
527 //   enum { Defined = 1 };//internal::is_same<typename DerType1::Scalar,typename DerType2::Scalar>::value };
528 //   typedef AutoDiffScalar<typename DerType1::PlainObject> ReturnType;
529 // };
530 
531 #define EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(FUNC,CODE) \
532   template<typename DerType> \
533   inline const Eigen::AutoDiffScalar< \
534   EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(typename Eigen::internal::remove_all<DerType>::type, typename Eigen::internal::traits<typename Eigen::internal::remove_all<DerType>::type>::Scalar, product) > \
535   FUNC(const Eigen::AutoDiffScalar<DerType>& x) { \
536     using namespace Eigen; \
537     EIGEN_UNUSED typedef typename Eigen::internal::traits<typename Eigen::internal::remove_all<DerType>::type>::Scalar Scalar; \
538     CODE; \
539   }
540 
541 template<typename DerType>
542 inline const AutoDiffScalar<DerType>& conj(const AutoDiffScalar<DerType>& x)  { return x; }
543 template<typename DerType>
544 inline const AutoDiffScalar<DerType>& real(const AutoDiffScalar<DerType>& x)  { return x; }
545 template<typename DerType>
546 inline typename DerType::Scalar imag(const AutoDiffScalar<DerType>&)    { return 0.; }
547 template<typename DerType, typename T>
548 inline AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> (min)(const AutoDiffScalar<DerType>& x, const T& y) {
549   typedef AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> ADS;
550   return (x <= y ? ADS(x) : ADS(y));
551 }
552 template<typename DerType, typename T>
553 inline AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> (max)(const AutoDiffScalar<DerType>& x, const T& y) {
554   typedef AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> ADS;
555   return (x >= y ? ADS(x) : ADS(y));
556 }
557 template<typename DerType, typename T>
558 inline AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> (min)(const T& x, const AutoDiffScalar<DerType>& y) {
559   typedef AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> ADS;
560   return (x < y ? ADS(x) : ADS(y));
561 }
562 template<typename DerType, typename T>
563 inline AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> (max)(const T& x, const AutoDiffScalar<DerType>& y) {
564   typedef AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> ADS;
565   return (x > y ? ADS(x) : ADS(y));
566 }
567 template<typename DerType>
568 inline AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> (min)(const AutoDiffScalar<DerType>& x, const AutoDiffScalar<DerType>& y) {
569   return (x.value() < y.value() ? x : y);
570 }
571 template<typename DerType>
572 inline AutoDiffScalar<typename Eigen::internal::remove_all<DerType>::type::PlainObject> (max)(const AutoDiffScalar<DerType>& x, const AutoDiffScalar<DerType>& y) {
573   return (x.value() >= y.value() ? x : y);
574 }
575 
576 
577 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(abs,
578   using std::abs;
579   return Eigen::MakeAutoDiffScalar(abs(x.value()), x.derivatives() * (x.value()<0 ? -1 : 1) );)
580 
581 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(abs2,
582   using numext::abs2;
583   return Eigen::MakeAutoDiffScalar(abs2(x.value()), x.derivatives() * (Scalar(2)*x.value()));)
584 
585 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(sqrt,
586   using std::sqrt;
587   Scalar sqrtx = sqrt(x.value());
588   return Eigen::MakeAutoDiffScalar(sqrtx,x.derivatives() * (Scalar(0.5) / sqrtx));)
589 
590 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(cos,
591   using std::cos;
592   using std::sin;
593   return Eigen::MakeAutoDiffScalar(cos(x.value()), x.derivatives() * (-sin(x.value())));)
594 
595 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(sin,
596   using std::sin;
597   using std::cos;
598   return Eigen::MakeAutoDiffScalar(sin(x.value()),x.derivatives() * cos(x.value()));)
599 
600 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(exp,
601   using std::exp;
602   Scalar expx = exp(x.value());
603   return Eigen::MakeAutoDiffScalar(expx,x.derivatives() * expx);)
604 
605 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(log,
606   using std::log;
607   return Eigen::MakeAutoDiffScalar(log(x.value()),x.derivatives() * (Scalar(1)/x.value()));)
608 
609 template<typename DerType>
610 inline const Eigen::AutoDiffScalar<
611 EIGEN_EXPR_BINARYOP_SCALAR_RETURN_TYPE(typename internal::remove_all<DerType>::type,typename internal::traits<typename internal::remove_all<DerType>::type>::Scalar,product) >
612 pow(const Eigen::AutoDiffScalar<DerType> &x, const typename internal::traits<typename internal::remove_all<DerType>::type>::Scalar &y)
613 {
614   using namespace Eigen;
615   using std::pow;
616   return Eigen::MakeAutoDiffScalar(pow(x.value(),y), x.derivatives() * (y * pow(x.value(),y-1)));
617 }
618 
619 
620 template<typename DerTypeA,typename DerTypeB>
621 inline const AutoDiffScalar<Matrix<typename internal::traits<typename internal::remove_all<DerTypeA>::type>::Scalar,Dynamic,1> >
622 atan2(const AutoDiffScalar<DerTypeA>& a, const AutoDiffScalar<DerTypeB>& b)
623 {
624   using std::atan2;
625   typedef typename internal::traits<typename internal::remove_all<DerTypeA>::type>::Scalar Scalar;
626   typedef AutoDiffScalar<Matrix<Scalar,Dynamic,1> > PlainADS;
627   PlainADS ret;
628   ret.value() = atan2(a.value(), b.value());
629 
630   Scalar squared_hypot = a.value() * a.value() + b.value() * b.value();
631 
632   // if (squared_hypot==0) the derivation is undefined and the following results in a NaN:
633   ret.derivatives() = (a.derivatives() * b.value() - a.value() * b.derivatives()) / squared_hypot;
634 
635   return ret;
636 }
637 
638 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(tan,
639   using std::tan;
640   using std::cos;
641   return Eigen::MakeAutoDiffScalar(tan(x.value()),x.derivatives() * (Scalar(1)/numext::abs2(cos(x.value()))));)
642 
643 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(asin,
644   using std::sqrt;
645   using std::asin;
646   return Eigen::MakeAutoDiffScalar(asin(x.value()),x.derivatives() * (Scalar(1)/sqrt(1-numext::abs2(x.value()))));)
647 
648 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(acos,
649   using std::sqrt;
650   using std::acos;
651   return Eigen::MakeAutoDiffScalar(acos(x.value()),x.derivatives() * (Scalar(-1)/sqrt(1-numext::abs2(x.value()))));)
652 
653 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(tanh,
654   using std::cosh;
655   using std::tanh;
656   return Eigen::MakeAutoDiffScalar(tanh(x.value()),x.derivatives() * (Scalar(1)/numext::abs2(cosh(x.value()))));)
657 
658 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(sinh,
659   using std::sinh;
660   using std::cosh;
661   return Eigen::MakeAutoDiffScalar(sinh(x.value()),x.derivatives() * cosh(x.value()));)
662 
663 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(cosh,
664   using std::sinh;
665   using std::cosh;
666   return Eigen::MakeAutoDiffScalar(cosh(x.value()),x.derivatives() * sinh(x.value()));)
667 
668 #undef EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY
669 
670 template<typename DerType> struct NumTraits<AutoDiffScalar<DerType> >
671   : NumTraits< typename NumTraits<typename internal::remove_all<DerType>::type::Scalar>::Real >
672 {
673   typedef typename internal::remove_all<DerType>::type DerTypeCleaned;
674   typedef AutoDiffScalar<Matrix<typename NumTraits<typename DerTypeCleaned::Scalar>::Real,DerTypeCleaned::RowsAtCompileTime,DerTypeCleaned::ColsAtCompileTime,
675                                 0, DerTypeCleaned::MaxRowsAtCompileTime, DerTypeCleaned::MaxColsAtCompileTime> > Real;
676   typedef AutoDiffScalar<DerType> NonInteger;
677   typedef AutoDiffScalar<DerType> Nested;
678   typedef typename NumTraits<typename DerTypeCleaned::Scalar>::Literal Literal;
679   enum{
680     RequireInitialization = 1
681   };
682 };
683 
684 }
685 
686 namespace std {
687 template <typename T>
688 class numeric_limits<Eigen::AutoDiffScalar<T> >
689   : public numeric_limits<typename T::Scalar> {};
690 
691 }  // namespace std
692 
693 #endif // EIGEN_AUTODIFF_SCALAR_H
694