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math/norm.hh
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25 
26 #ifndef MLN_FUN_MATH_NORM_HH
27 # define MLN_FUN_MATH_NORM_HH
28 
29 # include <mln/fun/unary.hh>
30 # include <mln/norm/all.hh>
31 
32 namespace mln
33 {
34 
35  // Common norm functions, reversible
36  namespace fun
37  {
38  namespace norm
39  {
40  struct l1 : unary<l1> {};
41 
42  struct l2 : unary<l2> {};
43 
44  struct linfty : unary<linfty> {};
45  }
46  }
47 
48  namespace trait
49  {
50 
51  namespace next
52  {
53 
54  template <unsigned n, typename T>
55  struct set_precise_unary_<mln::fun::norm::l1, mln::algebra::vec<n, T> >
56  {
57  typedef set_precise_unary_ ret;
58  typedef mln::algebra::vec<n, T> argument;
59  typedef argument& lvalue;
60  typedef mln_sum_product(argument,argument) result;
61 
62  static result read(const argument& x)
63  {
64  return mln::norm::l1(x);
65  }
66 
67  static void write(lvalue l, const result& x)
68  {
69  l = l / read(l) * x;
70  }
71  };
72 
73  template <unsigned n, typename T>
74  struct set_precise_unary_<mln::fun::norm::l2, mln::algebra::vec<n, T> >
75  {
76  typedef set_precise_unary_ ret;
77  typedef mln::algebra::vec<n, T> argument;
78  typedef argument& lvalue;
79  typedef mln_sum_product(argument,argument) result;
80 
81  static result read(const argument& x)
82  {
83  return mln::norm::l2(x);
84  }
85 
86  static void write(lvalue l, const result& x)
87  {
88  l = l / read(l) * x;
89  }
90  };
91 
92  template <unsigned n, typename T>
93  struct set_precise_unary_<mln::fun::norm::linfty, mln::algebra::vec<n, T> >
94  {
95  typedef set_precise_unary_ ret;
96  typedef mln::algebra::vec<n, T> argument;
97  typedef argument& lvalue;
98  typedef mln_sum_product(argument,argument) result;
99 
100  static result read(const argument& x)
101  {
102  return mln::norm::linfty(x);
103  }
104 
105  static void write(lvalue l, const result& x)
106  {
107  l = l / read(l) * x;
108  }
109  };
110 
111  } // end of namespace mln::trait::next
112 
113  } // end of namespace mln::trait
114 
115 } // end of namespace mln
116 
117 #endif /* ! NORM_HH */