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Sacado_CacheFad_Expression.hpp
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4 // Sacado Package
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6 //
7 // Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
8 // the U.S. Government retains certain rights in this software.
9 //
10 // This library is free software; you can redistribute it and/or modify
11 // it under the terms of the GNU Lesser General Public License as
12 // published by the Free Software Foundation; either version 2.1 of the
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15 // This library is distributed in the hope that it will be useful, but
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28 //
29 // The forward-mode AD classes in Sacado are a derivative work of the
30 // expression template classes in the Fad package by Nicolas Di Cesare.
31 // The following banner is included in the original Fad source code:
32 //
33 // ************ DO NOT REMOVE THIS BANNER ****************
34 //
35 // Nicolas Di Cesare <Nicolas.Dicesare@ann.jussieu.fr>
36 // http://www.ann.jussieu.fr/~dicesare
37 //
38 // CEMRACS 98 : C++ courses,
39 // templates : new C++ techniques
40 // for scientific computing
41 //
42 //********************************************************
43 //
44 // A short implementation ( not all operators and
45 // functions are overloaded ) of 1st order Automatic
46 // Differentiation in forward mode (FAD) using
47 // EXPRESSION TEMPLATES.
48 //
49 //********************************************************
50 // @HEADER
51 
52 #ifndef SACADO_CACHEFAD_EXPRESSION_HPP
53 #define SACADO_CACHEFAD_EXPRESSION_HPP
54 
55 #include "Sacado_Traits.hpp"
56 
57 namespace Sacado {
58 
59  namespace CacheFad {
60 
62 
69  template <typename> struct BaseExpr {};
70 
72 
76  template <typename ExprT>
77  class Expr {};
78 
80 
85  template <typename T>
86  struct ExprLevel {
87  static const unsigned value = 0;
88  };
89 
90  template <typename T>
91  struct ExprLevel< Expr<T> > {
92  static const unsigned value =
94  };
95 
97  template <typename T>
98  struct IsFadExpr {
99  static const bool value = false;
100  };
101 
102  template <typename T>
103  struct IsFadExpr< Expr<T> > {
104  static const bool value = true;
105  };
106 
108 
111  template <typename ConstT>
112  class ConstExpr {
113 
114  public:
115 
117  typedef ConstT value_type;
118 
121 
123  typedef ConstT base_expr_type;
124 
127  ConstExpr(const ConstT& constant) : constant_(constant) {}
128 
131  int size() const { return 0; }
132 
135  bool hasFastAccess() const { return 1; }
136 
139  void cache() const {}
140 
143  value_type val() const { return constant_; }
144 
147  value_type dx(int i) const { return value_type(0); }
148 
151  value_type fastAccessDx(int i) const { return value_type(0); }
152 
153  protected:
154 
156  const ConstT& constant_;
157 
158  }; // class ConstExpr
159 
160  } // namespace CacheFad
161 
162  template <typename T>
163  struct IsExpr< CacheFad::Expr<T> > {
164  static const bool value = true;
165  };
166 
167  template <typename T>
168  struct BaseExprType< CacheFad::Expr<T> > {
170  };
171 
172 } // namespace Sacado
173 
174 #include "Sacado_SFINAE_Macros.hpp"
175 
176 #endif // SACADO_CACHEFAD_EXPRESSION_HPP
Determine whether a given type is an expression.
const ConstT & constant_
The constant.
ConstT base_expr_type
Typename of base-expressions.
static const bool value
SACADO_INLINE_FUNCTION value_type dx(int i) const
Return derivative component i of operation.
Is a type an expression.
Constant expression template.
Meta-function for determining concrete base expression.
#define T
Definition: Sacado_rad.hpp:573
ConstT value_type
Typename of argument values.
Get the base Fad type from a view/expression.
SACADO_INLINE_FUNCTION value_type val() const
Return value of operation.
SACADO_INLINE_FUNCTION bool hasFastAccess() const
Return if operation has fast access.
SACADO_INLINE_FUNCTION value_type fastAccessDx(int i) const
Return derivative component i of operation.
SACADO_INLINE_FUNCTION int size() const
Return size of the derivative array of the operation.
ScalarType< value_type >::type scalar_type
Typename of scalar&#39;s (which may be different from ConstT)
#define SACADO_INLINE_FUNCTION
SACADO_INLINE_FUNCTION ConstExpr(const ConstT &constant)
Constructor.
SACADO_INLINE_FUNCTION void cache() const
Cache values.
Wrapper for a generic expression template.
Meta-function for determining nesting with an expression.