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37 #ifndef GMX_MATH_VECTYPES_H
38 #define GMX_MATH_VECTYPES_H
40 #include "gromacs/utility/real.h"
42 #define XX 0 /* Defines for indexing in */
43 #define YY 1 /* vectors */
45 #define DIM 3 /* Dimension of vectors */
47 typedef real rvec
[DIM
];
49 typedef double dvec
[DIM
];
51 typedef real matrix
[DIM
][DIM
];
53 typedef real tensor
[DIM
][DIM
];
55 typedef int ivec
[DIM
];
63 * C++ class for 3D vectors.
65 * \tparam ValueType Type
67 * This class provides a C++ version of rvec/dvec/ivec that can be put into STL
68 * containers etc. It is more or less a drop-in replacement for `rvec` and
69 * friends: it can be used in most contexts that accept the equivalent C type.
70 * However, there are two cases where explicit conversion is necessary:
71 * - An array of these objects needs to be converted with as_vec_array() (or
72 * convenience methods like as_rvec_array()).
73 * - Passing an RVec as a `const rvec &` parameter to a function needs an
74 * explicit call to as_vec(). The implicit conversion should work for this
75 * as well, but cppcheck parses the necessary implicit conversion operator
76 * incorrectly and MSVC fails to compile code that relies on the implicit
77 * conversion, so the explicit method is necessary.
79 * For the array conversion to work, the compiler should not add any extra
80 * alignment/padding in the layout of this class; that this actually works as
81 * intended is tested in the unit tests.
85 template <typename ValueType
>
89 //! Underlying raw C array type (rvec/dvec/ivec).
90 typedef ValueType RawArray
[DIM
];
92 //! Constructs default (uninitialized) vector.
94 //! Constructs a vector from given values.
95 BasicVector(ValueType x
, ValueType y
, ValueType z
)
102 * Constructs a vector from given values.
104 * This constructor is not explicit to support implicit conversions
105 * that allow, e.g., calling `std::vector<RVec>:``:push_back()` directly
106 * with an `rvec` parameter.
108 BasicVector(const RawArray x
)
114 //! Indexing operator to make the class work as the raw array.
115 ValueType
&operator[](int i
) { return x_
[i
]; }
116 //! Indexing operator to make the class work as the raw array.
117 ValueType
operator[](int i
) const { return x_
[i
]; }
118 // The conversion functions below could more accurately return
119 // RawArray &, but this fails with cppcheck and does not solve the
120 // issue with MSVC, so as_vec() should be used instead.
121 //! Makes BasicVector usable in contexts where a raw C array is expected.
122 operator ValueType
*() { return x_
; }
123 //! Makes BasicVector usable in contexts where a raw C array is expected.
124 operator const ValueType
*() const { return x_
; }
126 //! Converts to a raw C array where implicit conversion does not work.
127 RawArray
&as_vec() { return x_
; }
128 //! Converts to a raw C array where implicit conversion does not work.
129 const RawArray
&as_vec() const { return x_
; }
136 * Casts a gmx::BasicVector array into an equivalent raw C array.
138 template <typename ValueType
> static inline
139 typename BasicVector
<ValueType
>::RawArray
*
140 as_vec_array(BasicVector
<ValueType
> *x
)
142 return reinterpret_cast<typename BasicVector
<ValueType
>::RawArray
*>(x
);
146 * Casts a gmx::BasicVector array into an equivalent raw C array.
148 template <typename ValueType
> static inline
149 const typename BasicVector
<ValueType
>::RawArray
*
150 as_vec_array(const BasicVector
<ValueType
> *x
)
152 return reinterpret_cast<const typename BasicVector
<ValueType
>::RawArray
*>(x
);
155 //! Shorthand for C++ `rvec`-equivalent type.
156 typedef BasicVector
<real
> RVec
;
157 //! Casts a gmx::RVec array into an `rvec` array.
158 static inline rvec
*as_rvec_array(RVec
*x
)
160 return as_vec_array(x
);
162 //! Casts a gmx::RVec array into an `rvec` array.
163 static inline const rvec
*as_rvec_array(const RVec
*x
)
165 return as_vec_array(x
);
168 //! Shorthand for C++ `ivec`-equivalent type.
169 typedef BasicVector
<int> IVec
;