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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 /** \class AutoDiffScalar
34   * \brief A scalar type replacement with automatic differentation capability
35   *
36   * \param _DerType the vector type used to store/represent the derivatives. The base scalar type
37   *                 as well as the number of derivatives to compute are determined from this type.
38   *                 Typical choices include, e.g., \c Vector4f for 4 derivatives, or \c VectorXf
39   *                 if the number of derivatives is not known at compile time, and/or, the number
40   *                 of derivatives is large.
41   *                 Note that _DerType can also be a reference (e.g., \c VectorXf&) to wrap a
42   *                 existing vector into an AutoDiffScalar.
43   *                 Finally, _DerType can also be any Eigen compatible expression.
44   *
45   * This class represents a scalar value while tracking its respective derivatives using Eigen's expression
46   * template mechanism.
47   *
48   * It supports the following list of global math function:
49   *  - std::abs, std::sqrt, std::pow, std::exp, std::log, std::sin, std::cos,
50   *  - internal::abs, internal::sqrt, numext::pow, internal::exp, internal::log, internal::sin, internal::cos,
51   *  - internal::conj, internal::real, internal::imag, numext::abs2.
52   *
53   * AutoDiffScalar can be used as the scalar type of an Eigen::Matrix object. However,
54   * in that case, the expression template mechanism only occurs at the top Matrix level,
55   * while derivatives are computed right away.
56   *
57   */
58 
59 template<typename _DerType>
60 class AutoDiffScalar
61   : public internal::auto_diff_special_op
62             <_DerType, !internal::is_same<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar,
63                                         typename NumTraits<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar>::Real>::value>
64 {
65   public:
66     typedef internal::auto_diff_special_op
67             <_DerType, !internal::is_same<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar,
68                        typename NumTraits<typename internal::traits<typename internal::remove_all<_DerType>::type>::Scalar>::Real>::value> Base;
69     typedef typename internal::remove_all<_DerType>::type DerType;
70     typedef typename internal::traits<DerType>::Scalar Scalar;
71     typedef typename NumTraits<Scalar>::Real Real;
72 
73     using Base::operator+;
74     using Base::operator*;
75 
76     /** Default constructor without any initialization. */
AutoDiffScalar()77     AutoDiffScalar() {}
78 
79     /** Constructs an active scalar from its \a value,
80         and initializes the \a nbDer derivatives such that it corresponds to the \a derNumber -th variable */
AutoDiffScalar(const Scalar & value,int nbDer,int derNumber)81     AutoDiffScalar(const Scalar& value, int nbDer, int derNumber)
82       : m_value(value), m_derivatives(DerType::Zero(nbDer))
83     {
84       m_derivatives.coeffRef(derNumber) = Scalar(1);
85     }
86 
87     /** Conversion from a scalar constant to an active scalar.
88       * The derivatives are set to zero. */
AutoDiffScalar(const Real & value)89     /*explicit*/ AutoDiffScalar(const Real& value)
90       : m_value(value)
91     {
92       if(m_derivatives.size()>0)
93         m_derivatives.setZero();
94     }
95 
96     /** Constructs an active scalar from its \a value and derivatives \a der */
AutoDiffScalar(const Scalar & value,const DerType & der)97     AutoDiffScalar(const Scalar& value, const DerType& der)
98       : m_value(value), m_derivatives(der)
99     {}
100 
101     template<typename OtherDerType>
AutoDiffScalar(const AutoDiffScalar<OtherDerType> & other)102     AutoDiffScalar(const AutoDiffScalar<OtherDerType>& other)
103       : m_value(other.value()), m_derivatives(other.derivatives())
104     {}
105 
106     friend  std::ostream & operator << (std::ostream & s, const AutoDiffScalar& a)
107     {
108       return s << a.value();
109     }
110 
AutoDiffScalar(const AutoDiffScalar & other)111     AutoDiffScalar(const AutoDiffScalar& other)
112       : m_value(other.value()), m_derivatives(other.derivatives())
113     {}
114 
115     template<typename OtherDerType>
116     inline AutoDiffScalar& operator=(const AutoDiffScalar<OtherDerType>& other)
117     {
118       m_value = other.value();
119       m_derivatives = other.derivatives();
120       return *this;
121     }
122 
123     inline AutoDiffScalar& operator=(const AutoDiffScalar& other)
124     {
125       m_value = other.value();
126       m_derivatives = other.derivatives();
127       return *this;
128     }
129 
130 //     inline operator const Scalar& () const { return m_value; }
131 //     inline operator Scalar& () { return m_value; }
132 
value()133     inline const Scalar& value() const { return m_value; }
value()134     inline Scalar& value() { return m_value; }
135 
derivatives()136     inline const DerType& derivatives() const { return m_derivatives; }
derivatives()137     inline DerType& derivatives() { return m_derivatives; }
138 
139     inline bool operator< (const Scalar& other) const  { return m_value <  other; }
140     inline bool operator<=(const Scalar& other) const  { return m_value <= other; }
141     inline bool operator> (const Scalar& other) const  { return m_value >  other; }
142     inline bool operator>=(const Scalar& other) const  { return m_value >= other; }
143     inline bool operator==(const Scalar& other) const  { return m_value == other; }
144     inline bool operator!=(const Scalar& other) const  { return m_value != other; }
145 
146     friend inline bool operator< (const Scalar& a, const AutoDiffScalar& b) { return a <  b.value(); }
147     friend inline bool operator<=(const Scalar& a, const AutoDiffScalar& b) { return a <= b.value(); }
148     friend inline bool operator> (const Scalar& a, const AutoDiffScalar& b) { return a >  b.value(); }
149     friend inline bool operator>=(const Scalar& a, const AutoDiffScalar& b) { return a >= b.value(); }
150     friend inline bool operator==(const Scalar& a, const AutoDiffScalar& b) { return a == b.value(); }
151     friend inline bool operator!=(const Scalar& a, const AutoDiffScalar& b) { return a != b.value(); }
152 
153     template<typename OtherDerType> inline bool operator< (const AutoDiffScalar<OtherDerType>& b) const  { return m_value <  b.value(); }
154     template<typename OtherDerType> inline bool operator<=(const AutoDiffScalar<OtherDerType>& b) const  { return m_value <= b.value(); }
155     template<typename OtherDerType> inline bool operator> (const AutoDiffScalar<OtherDerType>& b) const  { return m_value >  b.value(); }
156     template<typename OtherDerType> inline bool operator>=(const AutoDiffScalar<OtherDerType>& b) const  { return m_value >= b.value(); }
157     template<typename OtherDerType> inline bool operator==(const AutoDiffScalar<OtherDerType>& b) const  { return m_value == b.value(); }
158     template<typename OtherDerType> inline bool operator!=(const AutoDiffScalar<OtherDerType>& b) const  { return m_value != b.value(); }
159 
160     inline const AutoDiffScalar<DerType&> operator+(const Scalar& other) const
161     {
162       return AutoDiffScalar<DerType&>(m_value + other, m_derivatives);
163     }
164 
165     friend inline const AutoDiffScalar<DerType&> operator+(const Scalar& a, const AutoDiffScalar& b)
166     {
167       return AutoDiffScalar<DerType&>(a + b.value(), b.derivatives());
168     }
169 
170 //     inline const AutoDiffScalar<DerType&> operator+(const Real& other) const
171 //     {
172 //       return AutoDiffScalar<DerType&>(m_value + other, m_derivatives);
173 //     }
174 
175 //     friend inline const AutoDiffScalar<DerType&> operator+(const Real& a, const AutoDiffScalar& b)
176 //     {
177 //       return AutoDiffScalar<DerType&>(a + b.value(), b.derivatives());
178 //     }
179 
180     inline AutoDiffScalar& operator+=(const Scalar& other)
181     {
182       value() += other;
183       return *this;
184     }
185 
186     template<typename OtherDerType>
187     inline const AutoDiffScalar<CwiseBinaryOp<internal::scalar_sum_op<Scalar>,const DerType,const typename internal::remove_all<OtherDerType>::type> >
188     operator+(const AutoDiffScalar<OtherDerType>& other) const
189     {
190       internal::make_coherent(m_derivatives, other.derivatives());
191       return AutoDiffScalar<CwiseBinaryOp<internal::scalar_sum_op<Scalar>,const DerType,const typename internal::remove_all<OtherDerType>::type> >(
192         m_value + other.value(),
193         m_derivatives + other.derivatives());
194     }
195 
196     template<typename OtherDerType>
197     inline AutoDiffScalar&
198     operator+=(const AutoDiffScalar<OtherDerType>& other)
199     {
200       (*this) = (*this) + other;
201       return *this;
202     }
203 
204     inline const AutoDiffScalar<DerType&> operator-(const Scalar& b) const
205     {
206       return AutoDiffScalar<DerType&>(m_value - b, m_derivatives);
207     }
208 
209     friend inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >
210     operator-(const Scalar& a, const AutoDiffScalar& b)
211     {
212       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >
213             (a - b.value(), -b.derivatives());
214     }
215 
216     inline AutoDiffScalar& operator-=(const Scalar& other)
217     {
218       value() -= other;
219       return *this;
220     }
221 
222     template<typename OtherDerType>
223     inline const AutoDiffScalar<CwiseBinaryOp<internal::scalar_difference_op<Scalar>, const DerType,const typename internal::remove_all<OtherDerType>::type> >
224     operator-(const AutoDiffScalar<OtherDerType>& other) const
225     {
226       internal::make_coherent(m_derivatives, other.derivatives());
227       return AutoDiffScalar<CwiseBinaryOp<internal::scalar_difference_op<Scalar>, const DerType,const typename internal::remove_all<OtherDerType>::type> >(
228         m_value - other.value(),
229         m_derivatives - other.derivatives());
230     }
231 
232     template<typename OtherDerType>
233     inline AutoDiffScalar&
234     operator-=(const AutoDiffScalar<OtherDerType>& other)
235     {
236       *this = *this - other;
237       return *this;
238     }
239 
240     inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >
241     operator-() const
242     {
243       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_opposite_op<Scalar>, const DerType> >(
244         -m_value,
245         -m_derivatives);
246     }
247 
248     inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >
249     operator*(const Scalar& other) const
250     {
251       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >(
252         m_value * other,
253         (m_derivatives * other));
254     }
255 
256     friend inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >
257     operator*(const Scalar& other, const AutoDiffScalar& a)
258     {
259       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >(
260         a.value() * other,
261         a.derivatives() * other);
262     }
263 
264 //     inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
265 //     operator*(const Real& other) const
266 //     {
267 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
268 //         m_value * other,
269 //         (m_derivatives * other));
270 //     }
271 //
272 //     friend inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
273 //     operator*(const Real& other, const AutoDiffScalar& a)
274 //     {
275 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
276 //         a.value() * other,
277 //         a.derivatives() * other);
278 //     }
279 
280     inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >
281     operator/(const Scalar& other) const
282     {
283       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >(
284         m_value / other,
285         (m_derivatives * (Scalar(1)/other)));
286     }
287 
288     friend inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >
289     operator/(const Scalar& other, const AutoDiffScalar& a)
290     {
291       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType> >(
292         other / a.value(),
293         a.derivatives() * (Scalar(-other) / (a.value()*a.value())));
294     }
295 
296 //     inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
297 //     operator/(const Real& other) const
298 //     {
299 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
300 //         m_value / other,
301 //         (m_derivatives * (Real(1)/other)));
302 //     }
303 //
304 //     friend inline const AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >
305 //     operator/(const Real& other, const AutoDiffScalar& a)
306 //     {
307 //       return AutoDiffScalar<typename CwiseUnaryOp<internal::scalar_multiple_op<Real>, DerType>::Type >(
308 //         other / a.value(),
309 //         a.derivatives() * (-Real(1)/other));
310 //     }
311 
312     template<typename OtherDerType>
313     inline const AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>,
314         const CwiseBinaryOp<internal::scalar_difference_op<Scalar>,
315           const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType>,
316           const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const typename internal::remove_all<OtherDerType>::type > > > >
317     operator/(const AutoDiffScalar<OtherDerType>& other) const
318     {
319       internal::make_coherent(m_derivatives, other.derivatives());
320       return AutoDiffScalar<CwiseUnaryOp<internal::scalar_multiple_op<Scalar>,
321         const CwiseBinaryOp<internal::scalar_difference_op<Scalar>,
322           const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType>,
323           const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const typename internal::remove_all<OtherDerType>::type > > > >(
324         m_value / other.value(),
325           ((m_derivatives * other.value()) - (m_value * other.derivatives()))
326         * (Scalar(1)/(other.value()*other.value())));
327     }
328 
329     template<typename OtherDerType>
330     inline const AutoDiffScalar<CwiseBinaryOp<internal::scalar_sum_op<Scalar>,
331         const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType>,
332         const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const typename internal::remove_all<OtherDerType>::type> > >
333     operator*(const AutoDiffScalar<OtherDerType>& other) const
334     {
335       internal::make_coherent(m_derivatives, other.derivatives());
336       return AutoDiffScalar<const CwiseBinaryOp<internal::scalar_sum_op<Scalar>,
337         const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const DerType>,
338         const CwiseUnaryOp<internal::scalar_multiple_op<Scalar>, const typename internal::remove_all<OtherDerType>::type > > >(
339         m_value * other.value(),
340         (m_derivatives * other.value()) + (m_value * other.derivatives()));
341     }
342 
343     inline AutoDiffScalar& operator*=(const Scalar& other)
344     {
345       *this = *this * other;
346       return *this;
347     }
348 
349     template<typename OtherDerType>
350     inline AutoDiffScalar& operator*=(const AutoDiffScalar<OtherDerType>& other)
351     {
352       *this = *this * other;
353       return *this;
354     }
355 
356     inline AutoDiffScalar& operator/=(const Scalar& other)
357     {
358       *this = *this / other;
359       return *this;
360     }
361 
362     template<typename OtherDerType>
363     inline AutoDiffScalar& operator/=(const AutoDiffScalar<OtherDerType>& other)
364     {
365       *this = *this / other;
366       return *this;
367     }
368 
369   protected:
370     Scalar m_value;
371     DerType m_derivatives;
372 
373 };
374 
375 namespace internal {
376 
377 template<typename _DerType>
378 struct auto_diff_special_op<_DerType, true>
379 //   : auto_diff_scalar_op<_DerType, typename NumTraits<Scalar>::Real,
380 //                            is_same<Scalar,typename NumTraits<Scalar>::Real>::value>
381 {
382   typedef typename remove_all<_DerType>::type DerType;
383   typedef typename traits<DerType>::Scalar Scalar;
384   typedef typename NumTraits<Scalar>::Real Real;
385 
386 //   typedef auto_diff_scalar_op<_DerType, typename NumTraits<Scalar>::Real,
387 //                            is_same<Scalar,typename NumTraits<Scalar>::Real>::value> Base;
388 
389 //   using Base::operator+;
390 //   using Base::operator+=;
391 //   using Base::operator-;
392 //   using Base::operator-=;
393 //   using Base::operator*;
394 //   using Base::operator*=;
395 
396   const AutoDiffScalar<_DerType>& derived() const { return *static_cast<const AutoDiffScalar<_DerType>*>(this); }
397   AutoDiffScalar<_DerType>& derived() { return *static_cast<AutoDiffScalar<_DerType>*>(this); }
398 
399 
400   inline const AutoDiffScalar<DerType&> operator+(const Real& other) const
401   {
402     return AutoDiffScalar<DerType&>(derived().value() + other, derived().derivatives());
403   }
404 
405   friend inline const AutoDiffScalar<DerType&> operator+(const Real& a, const AutoDiffScalar<_DerType>& b)
406   {
407     return AutoDiffScalar<DerType&>(a + b.value(), b.derivatives());
408   }
409 
410   inline AutoDiffScalar<_DerType>& operator+=(const Real& other)
411   {
412     derived().value() += other;
413     return derived();
414   }
415 
416 
417   inline const AutoDiffScalar<typename CwiseUnaryOp<scalar_multiple2_op<Scalar,Real>, DerType>::Type >
418   operator*(const Real& other) const
419   {
420     return AutoDiffScalar<typename CwiseUnaryOp<scalar_multiple2_op<Scalar,Real>, DerType>::Type >(
421       derived().value() * other,
422       derived().derivatives() * other);
423   }
424 
425   friend inline const AutoDiffScalar<typename CwiseUnaryOp<scalar_multiple2_op<Scalar,Real>, DerType>::Type >
426   operator*(const Real& other, const AutoDiffScalar<_DerType>& a)
427   {
428     return AutoDiffScalar<typename CwiseUnaryOp<scalar_multiple2_op<Scalar,Real>, DerType>::Type >(
429       a.value() * other,
430       a.derivatives() * other);
431   }
432 
433   inline AutoDiffScalar<_DerType>& operator*=(const Scalar& other)
434   {
435     *this = *this * other;
436     return derived();
437   }
438 };
439 
440 template<typename _DerType>
441 struct auto_diff_special_op<_DerType, false>
442 {
443   void operator*() const;
444   void operator-() const;
445   void operator+() const;
446 };
447 
448 template<typename A_Scalar, int A_Rows, int A_Cols, int A_Options, int A_MaxRows, int A_MaxCols, typename B>
449 struct make_coherent_impl<Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols>, B> {
450   typedef Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> A;
451   static void run(A& a, B& b) {
452     if((A_Rows==Dynamic || A_Cols==Dynamic) && (a.size()==0))
453     {
454       a.resize(b.size());
455       a.setZero();
456     }
457   }
458 };
459 
460 template<typename A, typename B_Scalar, int B_Rows, int B_Cols, int B_Options, int B_MaxRows, int B_MaxCols>
461 struct make_coherent_impl<A, Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> > {
462   typedef Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> B;
463   static void run(A& a, B& b) {
464     if((B_Rows==Dynamic || B_Cols==Dynamic) && (b.size()==0))
465     {
466       b.resize(a.size());
467       b.setZero();
468     }
469   }
470 };
471 
472 template<typename A_Scalar, int A_Rows, int A_Cols, int A_Options, int A_MaxRows, int A_MaxCols,
473          typename B_Scalar, int B_Rows, int B_Cols, int B_Options, int B_MaxRows, int B_MaxCols>
474 struct make_coherent_impl<Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols>,
475                              Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> > {
476   typedef Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> A;
477   typedef Matrix<B_Scalar, B_Rows, B_Cols, B_Options, B_MaxRows, B_MaxCols> B;
478   static void run(A& a, B& b) {
479     if((A_Rows==Dynamic || A_Cols==Dynamic) && (a.size()==0))
480     {
481       a.resize(b.size());
482       a.setZero();
483     }
484     else if((B_Rows==Dynamic || B_Cols==Dynamic) && (b.size()==0))
485     {
486       b.resize(a.size());
487       b.setZero();
488     }
489   }
490 };
491 
492 template<typename A_Scalar, int A_Rows, int A_Cols, int A_Options, int A_MaxRows, int A_MaxCols>
493 struct scalar_product_traits<Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols>,A_Scalar>
494 {
495   enum { Defined = 1 };
496   typedef Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> ReturnType;
497 };
498 
499 template<typename A_Scalar, int A_Rows, int A_Cols, int A_Options, int A_MaxRows, int A_MaxCols>
500 struct scalar_product_traits<A_Scalar, Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> >
501 {
502   enum { Defined = 1 };
503   typedef Matrix<A_Scalar, A_Rows, A_Cols, A_Options, A_MaxRows, A_MaxCols> ReturnType;
504 };
505 
506 template<typename DerType>
507 struct scalar_product_traits<AutoDiffScalar<DerType>,typename DerType::Scalar>
508 {
509   enum { Defined = 1 };
510   typedef AutoDiffScalar<DerType> ReturnType;
511 };
512 
513 template<typename DerType>
514 struct scalar_product_traits<typename DerType::Scalar,AutoDiffScalar<DerType> >
515 {
516   enum { Defined = 1 };
517   typedef AutoDiffScalar<DerType> ReturnType;
518 };
519 
520 } // end namespace internal
521 
522 #define EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(FUNC,CODE) \
523   template<typename DerType> \
524   inline const Eigen::AutoDiffScalar<Eigen::CwiseUnaryOp<Eigen::internal::scalar_multiple_op<typename Eigen::internal::traits<typename Eigen::internal::remove_all<DerType>::type>::Scalar>, const typename Eigen::internal::remove_all<DerType>::type> > \
525   FUNC(const Eigen::AutoDiffScalar<DerType>& x) { \
526     using namespace Eigen; \
527     typedef typename Eigen::internal::traits<typename Eigen::internal::remove_all<DerType>::type>::Scalar Scalar; \
528     typedef AutoDiffScalar<CwiseUnaryOp<Eigen::internal::scalar_multiple_op<Scalar>, const typename Eigen::internal::remove_all<DerType>::type> > ReturnType; \
529     CODE; \
530   }
531 
532 template<typename DerType>
533 inline const AutoDiffScalar<DerType>& conj(const AutoDiffScalar<DerType>& x)  { return x; }
534 template<typename DerType>
535 inline const AutoDiffScalar<DerType>& real(const AutoDiffScalar<DerType>& x)  { return x; }
536 template<typename DerType>
537 inline typename DerType::Scalar imag(const AutoDiffScalar<DerType>&)    { return 0.; }
538 template<typename DerType, typename T>
539 inline AutoDiffScalar<DerType> (min)(const AutoDiffScalar<DerType>& x, const T& y)    { return (x <= y ? x : y); }
540 template<typename DerType, typename T>
541 inline AutoDiffScalar<DerType> (max)(const AutoDiffScalar<DerType>& x, const T& y)    { return (x >= y ? x : y); }
542 template<typename DerType, typename T>
543 inline AutoDiffScalar<DerType> (min)(const T& x, const AutoDiffScalar<DerType>& y)    { return (x < y ? x : y); }
544 template<typename DerType, typename T>
545 inline AutoDiffScalar<DerType> (max)(const T& x, const AutoDiffScalar<DerType>& y)    { return (x > y ? x : y); }
546 
547 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(abs,
548   using std::abs;
549   return ReturnType(abs(x.value()), x.derivatives() * (x.value()<0 ? -1 : 1) );)
550 
551 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(abs2,
552   using numext::abs2;
553   return ReturnType(abs2(x.value()), x.derivatives() * (Scalar(2)*x.value()));)
554 
555 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(sqrt,
556   using std::sqrt;
557   Scalar sqrtx = sqrt(x.value());
558   return ReturnType(sqrtx,x.derivatives() * (Scalar(0.5) / sqrtx));)
559 
560 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(cos,
561   using std::cos;
562   using std::sin;
563   return ReturnType(cos(x.value()), x.derivatives() * (-sin(x.value())));)
564 
565 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(sin,
566   using std::sin;
567   using std::cos;
568   return ReturnType(sin(x.value()),x.derivatives() * cos(x.value()));)
569 
570 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(exp,
571   using std::exp;
572   Scalar expx = exp(x.value());
573   return ReturnType(expx,x.derivatives() * expx);)
574 
575 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(log,
576   using std::log;
577   return ReturnType(log(x.value()),x.derivatives() * (Scalar(1)/x.value()));)
578 
579 template<typename DerType>
580 inline const Eigen::AutoDiffScalar<Eigen::CwiseUnaryOp<Eigen::internal::scalar_multiple_op<typename Eigen::internal::traits<DerType>::Scalar>, const DerType> >
581 pow(const Eigen::AutoDiffScalar<DerType>& x, typename Eigen::internal::traits<DerType>::Scalar y)
582 {
583   using namespace Eigen;
584   typedef typename Eigen::internal::traits<DerType>::Scalar Scalar;
585   return AutoDiffScalar<CwiseUnaryOp<Eigen::internal::scalar_multiple_op<Scalar>, const DerType> >(
586     std::pow(x.value(),y),
587     x.derivatives() * (y * std::pow(x.value(),y-1)));
588 }
589 
590 
591 template<typename DerTypeA,typename DerTypeB>
592 inline const AutoDiffScalar<Matrix<typename internal::traits<DerTypeA>::Scalar,Dynamic,1> >
593 atan2(const AutoDiffScalar<DerTypeA>& a, const AutoDiffScalar<DerTypeB>& b)
594 {
595   using std::atan2;
596   using std::max;
597   typedef typename internal::traits<DerTypeA>::Scalar Scalar;
598   typedef AutoDiffScalar<Matrix<Scalar,Dynamic,1> > PlainADS;
599   PlainADS ret;
600   ret.value() = atan2(a.value(), b.value());
601 
602   Scalar tmp2 = a.value() * a.value();
603   Scalar tmp3 = b.value() * b.value();
604   Scalar tmp4 = tmp3/(tmp2+tmp3);
605 
606   if (tmp4!=0)
607     ret.derivatives() = (a.derivatives() * b.value() - a.value() * b.derivatives()) * (tmp2+tmp3);
608 
609   return ret;
610 }
611 
612 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(tan,
613   using std::tan;
614   using std::cos;
615   return ReturnType(tan(x.value()),x.derivatives() * (Scalar(1)/numext::abs2(cos(x.value()))));)
616 
617 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(asin,
618   using std::sqrt;
619   using std::asin;
620   return ReturnType(asin(x.value()),x.derivatives() * (Scalar(1)/sqrt(1-numext::abs2(x.value()))));)
621 
622 EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY(acos,
623   using std::sqrt;
624   using std::acos;
625   return ReturnType(acos(x.value()),x.derivatives() * (Scalar(-1)/sqrt(1-numext::abs2(x.value()))));)
626 
627 #undef EIGEN_AUTODIFF_DECLARE_GLOBAL_UNARY
628 
629 template<typename DerType> struct NumTraits<AutoDiffScalar<DerType> >
630   : NumTraits< typename NumTraits<typename DerType::Scalar>::Real >
631 {
632   typedef AutoDiffScalar<Matrix<typename NumTraits<typename DerType::Scalar>::Real,DerType::RowsAtCompileTime,DerType::ColsAtCompileTime> > Real;
633   typedef AutoDiffScalar<DerType> NonInteger;
634   typedef AutoDiffScalar<DerType>& Nested;
635   enum{
636     RequireInitialization = 1
637   };
638 };
639 
640 }
641 
642 #endif // EIGEN_AUTODIFF_SCALAR_H
643