1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2008-2016 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_NULLARY_FUNCTORS_H
11#define EIGEN_NULLARY_FUNCTORS_H
12
13namespace Eigen {
14
15namespace internal {
16
17template<typename Scalar>
18struct scalar_constant_op {
19 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE scalar_constant_op(const scalar_constant_op& other) : m_other(other.m_other) { }
20 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE scalar_constant_op(const Scalar& other) : m_other(other) { }
21 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() () const { return m_other; }
22 template<typename PacketType>
23 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const PacketType packetOp() const { return internal::pset1<PacketType>(m_other); }
24 const Scalar m_other;
25};
26template<typename Scalar>
27struct functor_traits<scalar_constant_op<Scalar> >
28{ enum { Cost = 0 /* as the constant value should be loaded in register only once for the whole expression */,
29 PacketAccess = packet_traits<Scalar>::Vectorizable, IsRepeatable = true }; };
30
31template<typename Scalar> struct scalar_identity_op {
32 EIGEN_EMPTY_STRUCT_CTOR(scalar_identity_op)
33 template<typename IndexType>
34 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (IndexType row, IndexType col) const { return row==col ? Scalar(1) : Scalar(0); }
35};
36template<typename Scalar>
37struct functor_traits<scalar_identity_op<Scalar> >
38{ enum { Cost = NumTraits<Scalar>::AddCost, PacketAccess = false, IsRepeatable = true }; };
39
40template <typename Scalar, typename Packet, bool IsInteger> struct linspaced_op_impl;
41
42template <typename Scalar, typename Packet>
43struct linspaced_op_impl<Scalar,Packet,/*IsInteger*/false>
44{
45 linspaced_op_impl(const Scalar& low, const Scalar& high, Index num_steps) :
46 m_low(low), m_high(high), m_size1(num_steps==1 ? 1 : num_steps-1), m_step(num_steps==1 ? Scalar() : (high-low)/Scalar(num_steps-1)),
47 m_flip(numext::abs(high)<numext::abs(low))
48 {}
49
50 template<typename IndexType>
51 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (IndexType i) const {
52 typedef typename NumTraits<Scalar>::Real RealScalar;
53 if(m_flip)
54 return (i==0)? m_low : (m_high - RealScalar(m_size1-i)*m_step);
55 else
56 return (i==m_size1)? m_high : (m_low + RealScalar(i)*m_step);
57 }
58
59 template<typename IndexType>
60 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Packet packetOp(IndexType i) const
61 {
62 // Principle:
63 // [low, ..., low] + ( [step, ..., step] * ( [i, ..., i] + [0, ..., size] ) )
64 if(m_flip)
65 {
66 Packet pi = plset<Packet>(Scalar(i-m_size1));
67 Packet res = padd(pset1<Packet>(m_high), pmul(pset1<Packet>(m_step), pi));
68 if(i==0)
69 res = pinsertfirst(res, m_low);
70 return res;
71 }
72 else
73 {
74 Packet pi = plset<Packet>(Scalar(i));
75 Packet res = padd(pset1<Packet>(m_low), pmul(pset1<Packet>(m_step), pi));
76 if(i==m_size1-unpacket_traits<Packet>::size+1)
77 res = pinsertlast(res, m_high);
78 return res;
79 }
80 }
81
82 const Scalar m_low;
83 const Scalar m_high;
84 const Index m_size1;
85 const Scalar m_step;
86 const bool m_flip;
87};
88
89template <typename Scalar, typename Packet>
90struct linspaced_op_impl<Scalar,Packet,/*IsInteger*/true>
91{
92 linspaced_op_impl(const Scalar& low, const Scalar& high, Index num_steps) :
93 m_low(low),
94 m_multiplier((high-low)/convert_index<Scalar>(num_steps<=1 ? 1 : num_steps-1)),
95 m_divisor(convert_index<Scalar>((high>=low?num_steps:-num_steps)+(high-low))/((numext::abs(high-low)+1)==0?1:(numext::abs(high-low)+1))),
96 m_use_divisor(num_steps>1 && (numext::abs(high-low)+1)<num_steps)
97 {}
98
99 template<typename IndexType>
100 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
101 const Scalar operator() (IndexType i) const
102 {
103 if(m_use_divisor) return m_low + convert_index<Scalar>(i)/m_divisor;
104 else return m_low + convert_index<Scalar>(i)*m_multiplier;
105 }
106
107 const Scalar m_low;
108 const Scalar m_multiplier;
109 const Scalar m_divisor;
110 const bool m_use_divisor;
111};
112
113// ----- Linspace functor ----------------------------------------------------------------
114
115// Forward declaration (we default to random access which does not really give
116// us a speed gain when using packet access but it allows to use the functor in
117// nested expressions).
118template <typename Scalar, typename PacketType> struct linspaced_op;
119template <typename Scalar, typename PacketType> struct functor_traits< linspaced_op<Scalar,PacketType> >
120{
121 enum
122 {
123 Cost = 1,
124 PacketAccess = (!NumTraits<Scalar>::IsInteger) && packet_traits<Scalar>::HasSetLinear && packet_traits<Scalar>::HasBlend,
125 /*&& ((!NumTraits<Scalar>::IsInteger) || packet_traits<Scalar>::HasDiv),*/ // <- vectorization for integer is currently disabled
126 IsRepeatable = true
127 };
128};
129template <typename Scalar, typename PacketType> struct linspaced_op
130{
131 linspaced_op(const Scalar& low, const Scalar& high, Index num_steps)
132 : impl((num_steps==1 ? high : low),high,num_steps)
133 {}
134
135 template<typename IndexType>
136 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar operator() (IndexType i) const { return impl(i); }
137
138 template<typename Packet,typename IndexType>
139 EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Packet packetOp(IndexType i) const { return impl.packetOp(i); }
140
141 // This proxy object handles the actual required temporaries and the different
142 // implementations (integer vs. floating point).
143 const linspaced_op_impl<Scalar,PacketType,NumTraits<Scalar>::IsInteger> impl;
144};
145
146// Linear access is automatically determined from the operator() prototypes available for the given functor.
147// If it exposes an operator()(i,j), then we assume the i and j coefficients are required independently
148// and linear access is not possible. In all other cases, linear access is enabled.
149// Users should not have to deal with this structure.
150template<typename Functor> struct functor_has_linear_access { enum { ret = !has_binary_operator<Functor>::value }; };
151
152// For unreliable compilers, let's specialize the has_*ary_operator
153// helpers so that at least built-in nullary functors work fine.
154#if !( (EIGEN_COMP_MSVC>1600) || (EIGEN_GNUC_AT_LEAST(4,8)) || (EIGEN_COMP_ICC>=1600))
155template<typename Scalar,typename IndexType>
156struct has_nullary_operator<scalar_constant_op<Scalar>,IndexType> { enum { value = 1}; };
157template<typename Scalar,typename IndexType>
158struct has_unary_operator<scalar_constant_op<Scalar>,IndexType> { enum { value = 0}; };
159template<typename Scalar,typename IndexType>
160struct has_binary_operator<scalar_constant_op<Scalar>,IndexType> { enum { value = 0}; };
161
162template<typename Scalar,typename IndexType>
163struct has_nullary_operator<scalar_identity_op<Scalar>,IndexType> { enum { value = 0}; };
164template<typename Scalar,typename IndexType>
165struct has_unary_operator<scalar_identity_op<Scalar>,IndexType> { enum { value = 0}; };
166template<typename Scalar,typename IndexType>
167struct has_binary_operator<scalar_identity_op<Scalar>,IndexType> { enum { value = 1}; };
168
169template<typename Scalar, typename PacketType,typename IndexType>
170struct has_nullary_operator<linspaced_op<Scalar,PacketType>,IndexType> { enum { value = 0}; };
171template<typename Scalar, typename PacketType,typename IndexType>
172struct has_unary_operator<linspaced_op<Scalar,PacketType>,IndexType> { enum { value = 1}; };
173template<typename Scalar, typename PacketType,typename IndexType>
174struct has_binary_operator<linspaced_op<Scalar,PacketType>,IndexType> { enum { value = 0}; };
175
176template<typename Scalar,typename IndexType>
177struct has_nullary_operator<scalar_random_op<Scalar>,IndexType> { enum { value = 1}; };
178template<typename Scalar,typename IndexType>
179struct has_unary_operator<scalar_random_op<Scalar>,IndexType> { enum { value = 0}; };
180template<typename Scalar,typename IndexType>
181struct has_binary_operator<scalar_random_op<Scalar>,IndexType> { enum { value = 0}; };
182#endif
183
184} // end namespace internal
185
186} // end namespace Eigen
187
188#endif // EIGEN_NULLARY_FUNCTORS_H
189