From 40c40507f9d4e5e8d66fcae0c5727cb1e7cd3e82 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 18 May 2012 17:56:24 +1000
Subject: [PATCH] Give vector and point templated dimension size

---
 matrix.cpp |  40 +++++---
 matrix.hpp |   4 +-
 point.cpp  | 122 ++++++++++++++++-------
 point.hpp  |  40 +++++---
 region.cpp |  14 +--
 region.hpp |  10 +-
 vector.cpp | 285 +++++++++++++++++++++++++++++++++--------------------
 vector.hpp |  64 +++++++-----
 8 files changed, 380 insertions(+), 199 deletions(-)

diff --git a/matrix.cpp b/matrix.cpp
index f8b57dc3..daa18c3c 100644
--- a/matrix.cpp
+++ b/matrix.cpp
@@ -103,18 +103,24 @@ matrix::operator* (const matrix &rhs) const {
 }
 
 
-util::point
-matrix::to_local (const util::point &p) const {
+util::point<3>
+matrix::to_local (const util::point<3> &p) const {
     CHECK_SOFT (is_affine ());
 
-    return { p.x * values[0][0] + p.y * values[0][1] + p.z * values[0][2]  + values[0][3],
-             p.x * values[1][0] + p.y * values[1][1] + p.z * values[1][2]  + values[1][3],
-             p.x * values[2][0] + p.y * values[2][1] + p.z * values[2][2]  + values[2][3] };
+    return { p.x * values[0][0] +
+             p.y * values[0][1] +
+             p.z * values[0][2] + values[0][3],
+             p.x * values[1][0] +
+             p.y * values[1][1] +
+             p.z * values[1][2] + values[1][3],
+             p.x * values[2][0] +
+             p.y * values[2][1] +
+             p.z * values[2][2] + values[2][3] };
 }
 
 
-util::point
-matrix::to_global (const util::point &p) const {
+util::point<3>
+matrix::to_global (const util::point<3> &p) const {
     return inverse ().to_local (p);
 }
 
@@ -145,10 +151,22 @@ matrix::ZEROES = { { { 0.0, 0.0, 0.0, 0.0 },
 
 std::ostream&
 operator<< (std::ostream &os, const matrix &m) {
-    os << "{ {" << m.values[0][0] << ", " << m.values[0][1] << ", " << m.values[0][2] << ", " << m.values[0][3] << "}, "
-       <<   "{" << m.values[1][0] << ", " << m.values[1][1] << ", " << m.values[1][2] << ", " << m.values[1][3] << "}, "
-       <<   "{" << m.values[2][0] << ", " << m.values[2][1] << ", " << m.values[2][2] << ", " << m.values[2][3] << "}, "
-       <<   "{" << m.values[3][0] << ", " << m.values[3][1] << ", " << m.values[3][2] << ", " << m.values[3][3] << "} }";
+    os << "{ {" << m.values[0][0] << ", "
+                << m.values[0][1] << ", "
+                << m.values[0][2] << ", "
+                << m.values[0][3] << "}, "
+       <<   "{" << m.values[1][0] << ", "
+                << m.values[1][1] << ", "
+                << m.values[1][2] << ", "
+                << m.values[1][3] << "}, "
+       <<   "{" << m.values[2][0] << ", "
+                << m.values[2][1] << ", "
+                << m.values[2][2] << ", "
+                << m.values[2][3] << "}, "
+       <<   "{" << m.values[3][0] << ", "
+                << m.values[3][1] << ", "
+                << m.values[3][2] << ", "
+                << m.values[3][3] << "} }";
 
     return os;
 }
diff --git a/matrix.hpp b/matrix.hpp
index 8b7ee993..dc1e5bf6 100644
--- a/matrix.hpp
+++ b/matrix.hpp
@@ -29,8 +29,8 @@ namespace util {
 
         matrix operator* (const matrix&) const;
 
-        point to_local  (const point &p) const;
-        point to_global (const point &p) const;
+        point<3> to_local  (const point<3> &p) const;
+        point<3> to_global (const point<3> &p) const;
 
         bool is_affine (void) const;
 
diff --git a/point.cpp b/point.cpp
index d28441e7..55ccdfc9 100644
--- a/point.cpp
+++ b/point.cpp
@@ -24,79 +24,129 @@
 #include <cmath>
 
 using namespace std;
-using namespace util;
 
 
+template <size_t S>
+util::point<S>::point ()
+{ ; }
+
+
+template <size_t S>
 double
-point::distance (const point &other) const {
+util::point<S>::distance (const util::point<S> &other) const {
     return sqrt (distance2 (other));
 }
 
 
+template <size_t S>
 double
-point::distance2 (const point &other) const {
-    return (x - other.x) * (x - other.x) +
-           (y - other.y) * (y - other.y) +
-           (z - other.z) * (z - other.z);
+util::point<S>::distance2 (const util::point<S> &other) const {
+    double total = 0.0;
+
+    for (size_t i = 0; i < S; ++i)
+        total += pow2 (this->data[i] - other.data[i]);
+    return total;
 }
 
 
+
+template <size_t S>
 double
-point::manhattan (const point &other) const {
-    return fabs (x - other.x) + 
-           fabs (y - other.y) +
-           fabs (z - other.z);
+util::point<S>::manhattan (const util::point<S> &other) const {
+    double total = 0.0;
+
+    for (size_t i = 0; i < S; ++i)
+        total += fabs (this->data[i] - other.data[i]);
+    return total;
 }
 
 
-point&
-point::operator*= (double f) {
-    x *= f;
-    y *= f;
-    z *= f;
+template <size_t S>
+util::point<S>&
+util::point<S>::operator*= (double f) {
+    for (double &i: this->data)
+        i *= f;
 
     return *this;
 }
 
 
-point
-point::operator* (double f) const {
-    return { x * f, y * f, z * f };
+template <size_t S>
+util::point<S>
+util::point<S>::operator* (double f) const {
+    util::point<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] * f;
+    return out;
 }
 
 
-point
-point::operator+ (const vector &rhs) const {
-    return { x + rhs.x, y + rhs.y, z + rhs.z };
+template <size_t S>
+util::point<S>
+util::point<S>::operator+ (const util::vector<S> &rhs) const {
+    util::point<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] + rhs.data[i];
+    return out;
 }
 
 
-point&
-point::operator+= (const vector &rhs) {
-    x += rhs.x;
-    y += rhs.y;
-    z += rhs.z;
-
+template <size_t S>
+util::point<S>&
+util::point<S>::operator+= (const util::vector<S> &rhs) {
+    for (size_t i = 0; i < S; ++i)
+        this->data[i] += rhs.data[i];
     return *this;
 }
 
 
-util::vector
-point::operator- (const point &rhs) const {
-    return { x - rhs.x, y - rhs.y, z - rhs.z };
+template <size_t S>
+util::point<S>
+util::point<S>::operator- (const util::point<S> &rhs) const {
+    util::point<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] - rhs.data[i];
+    return out;
 }
 
 
+template <size_t S>
+util::vector<S>
+util::point<S>::to (const util::point<S> &rhs) const {
+    util::vector<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = rhs.data[i] - this->data[i];
+    return out;
+}
+
+
+template <size_t S>
 void
-point::sanity (void) const {
-    CHECK_SOFT (!std::isnan (x));
-    CHECK_SOFT (!std::isnan (y));
-    CHECK_SOFT (!std::isnan (z));
+util::point<S>::sanity (void) const {
+    CHECK_SOFT (std::all_of (begin (this->data),
+                             end   (this->data),
+                             [] (double i) { return !std::isnan (i); }));
 }
 
 
+template <size_t S>
 std::ostream&
-operator<< (std::ostream &os, const point &p) {
-    os << "point(" << p.x << ", " << p.y << ", " << p.z << ")";
+util::operator<< (std::ostream &os, const util::point<S> &p) {
+    os << "point" << S << "(";
+    os << p.data[0];
+
+    for (size_t i = 1; i < S; ++i)
+        os << ", " << p.data[i];
+
+    os << ")";
     return os;
 }
+
+
+template struct util::point<1>;
+template struct util::point<2>;
+template struct util::point<3>;
diff --git a/point.hpp b/point.hpp
index f919c7f7..206d443b 100644
--- a/point.hpp
+++ b/point.hpp
@@ -20,31 +20,49 @@
 #ifndef __UTIL_POINT_HPP
 #define __UTIL_POINT_HPP
 
+#include "vector.hpp"
+#include "detail/coord.hpp"
+
+#include <array>
+#include <initializer_list>
 #include <iostream>
 
-#include "vector.hpp"
-
 namespace util {
-    /// A three dimensional position in space.
-    struct point {
-        double x, y, z;
+    /// An n-dimensional position in space.
+    template <size_t S>
+    struct point : public detail::coord_data<S> {
+        static_assert (S > 0, "point dimensions must be strictly positive.");
+
+        point ();
+
+        template <typename... T>
+        point (T ...t): detail::coord_data<S> {std::forward<T> (t)...} { ; }
 
         double distance  (const point &) const;
         double distance2 (const point &) const;
         double manhattan (const point &) const;
 
-        point& operator*= (double);
-        point  operator*  (double) const;
+        point<S>& operator*= (double);
+        point<S>  operator*  (double) const;
+        point<S>  operator-  (const point<S>&) const;
 
-        point  operator+  (const vector&) const;
-        point& operator+= (const vector&);
-        vector operator-  (const point&) const;
+        point<S>  operator+  (const util::vector<S>&) const;
+        point<S>& operator+= (const util::vector<S>&);
+
+        util::vector<S> to (const point<S>&) const;
+
+        template <size_t D> point<D> redim (void);
 
         void sanity (void) const;
     };
+
+    typedef point<2> point2;
+    typedef point<3> point3;
+
+    template <size_t S>
+    std::ostream& operator<< (std::ostream&, const util::point<S>&);
 }
 
-std::ostream& operator<< (std::ostream&, const util::point&);
 
 
 #endif // __UTIL_POINT_HPP
diff --git a/region.cpp b/region.cpp
index f03ea967..80555ef8 100644
--- a/region.cpp
+++ b/region.cpp
@@ -41,7 +41,7 @@ region<T>::region (T _x, T _y, T _w, T _h):
 
 template <typename T>
 region<T>&
-region<T>::operator+= (const vector &rhs) {
+region<T>::operator+= (const vector<2> &rhs) {
     x += rhs.x;
     y += rhs.y;
 
@@ -69,25 +69,25 @@ region<T>::empty (void) const
 
 
 template <typename T>
-point
+point<2>
 region<T>::base (void) const {
-    return { static_cast<double> (x), static_cast<double> (y), 0.0 };
+    return { static_cast<double> (x), static_cast<double> (y) };
 }
 
 
 template <typename T>
-point
+point<2>
 region<T>::centre (void) const {
     double cx = x + static_cast<T>(w / 2.0),
            cy = y + static_cast<T>(h / 2.0);
 
-    return { cx, cy, 0.0 };
+    return { cx, cy };
 }
 
 
 template <typename T>
 bool
-region<T>::includes (const point &p) const {
+region<T>::includes (const point<2> &p) const {
     return p.x >= x &&
            p.y >= y &&
            p.x <= x + w &&
@@ -97,7 +97,7 @@ region<T>::includes (const point &p) const {
 
 template <typename T>
 bool
-region<T>::contains (const point& p) const {
+region<T>::contains (const point<2> &p) const {
     return p.x > x &&
            p.y > y &&
            p.x < x + w &&
diff --git a/region.hpp b/region.hpp
index 68a59a3b..6d5e84d7 100644
--- a/region.hpp
+++ b/region.hpp
@@ -34,18 +34,18 @@ namespace util {
 
         region (T _x, T _y, T _w, T _h);
 
-        region& operator +=(const vector& rhs);
+        region& operator +=(const vector<2>& rhs);
 
         T area     (void) const;
         T diameter (void) const;
 
         bool empty (void) const;
 
-        point base   (void) const;
-        point centre (void) const;
+        point<2> base   (void) const;
+        point<2> centre (void) const;
 
-        bool includes (const point&) const; // inclusive of borders
-        bool contains (const point&) const; // exclusive of borders
+        bool includes (const point<2>&) const; // inclusive of borders
+        bool contains (const point<2>&) const; // exclusive of borders
         bool overlaps (const region<T>&) const; // exclusive of borders
 
         region overlap (const region<T>&) const;
diff --git a/vector.cpp b/vector.cpp
index 014b8f8f..c0c7196a 100644
--- a/vector.cpp
+++ b/vector.cpp
@@ -29,141 +29,193 @@
 
 
 using namespace util;
+using std::begin;
+using std::end;
 
-util::vector
-util::vector::operator* (double rhs) const {
-    return { rhs * x, rhs * y, rhs * z };
+
+template <size_t S>
+util::vector<S>::vector ()
+{ ; }
+
+
+//template <size_t S>
+//util::vector<S>::vector (const std::initializer_list<double> &_data) {
+//    CHECK (_data.size () == S);
+//
+//    std::copy (std::begin (_data),
+//               std::end   (_data),
+//               std::begin (this->data));
+//}
+
+
+template <size_t S>
+util::vector<S>
+util::vector<S>::operator* (double rhs) const {
+    util::vector<S> out;
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] * rhs;
+    return out;
 }
 
 
-vector&
-vector::operator*= (double rhs) {
-    x *= rhs;
-    y *= rhs;
-    z *= rhs;
+template <size_t S>
+util::vector<S>&
+util::vector<S>::operator*= (double rhs) {
+    for (double &i: this->data)
+        i *= rhs;
 
     return *this;
 }
 
 
-util::vector
-util::vector::operator* (const vector &rhs) const {
-    return { x * rhs.x, y * rhs.y, z * rhs.z };
+template <size_t S>
+util::vector<S>
+util::vector<S>::operator* (const util::vector<S> &rhs) const {
+    util::vector<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] * rhs.data[i];
+    return out;
 }
 
 
-util::vector&
-util::vector::operator*= (const vector &rhs) {
-    x *= rhs.x;
-    y *= rhs.y;
-    z *= rhs.z;
+template <size_t S>
+util::vector<S>&
+util::vector<S>::operator*= (const util::vector<S> &rhs) {
+    for (size_t i = 0; i < S; ++i)
+        this->data[i] *= rhs.data[i];
 
     return *this;
 }
 
 
-vector
-vector::operator+ (const vector &rhs) const {
-    return { x + rhs.x, y + rhs.y, z + rhs.z };
+template <size_t S>
+util::vector<S>
+util::vector<S>::operator+ (const util::vector<S> &rhs) const {
+    util::vector<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] + rhs.data[i];
+    return out;
 }
 
 
-vector
-vector::operator- (void) const {
-    return { -x, -y, -z };
+template <size_t S>
+util::vector<S>
+util::vector<S>::operator- (void) const {
+    util::vector<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = -this->data[i];
+    return out;
 }
 
 
-vector
-vector::operator- (const vector &rhs) const
-    { return { x - rhs.x, y - rhs.y, z - rhs.z }; }
+template <size_t S>
+util::vector<S>
+util::vector<S>::operator- (const util::vector<S> &rhs) const {
+    util::vector<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] - rhs.data[i];
+    return out;
+}
 
 
-vector&
-vector::operator-= (const vector &rhs) {
-    x -= rhs.x;
-    y -= rhs.y;
-    z -= rhs.z;
+template <size_t S>
+util::vector<S>&
+util::vector<S>::operator-= (const util::vector<S> &rhs) {
+    for (size_t i = 0; i < S; ++i)
+        this->data[i] -= rhs.data[i];
 
     return *this;
 }
 
 
-vector&
-vector::operator+= (const vector &rhs) {
-    x += rhs.x;
-    y += rhs.y;
-    z += rhs.z;
+template <size_t S>
+util::vector<S>&
+util::vector<S>::operator+= (const util::vector<S> &rhs) {
+    for (size_t i = 0; i < S; ++i)
+        this->data[i] += rhs.data[i];
 
     return *this;
 }
 
 
-vector&
-vector::operator= (const vector &rhs) {
-    x = rhs.x;
-    y = rhs.y;
-    z = rhs.z;
+template <size_t S>
+util::vector<S>&
+util::vector<S>::operator= (const util::vector<S> &rhs) {
+    std::copy (begin (rhs.data), end (rhs.data), begin (this->data));
 
     return *this;
 }
 
 
+template <size_t S>
 bool
-vector::operator== (const vector &rhs) const {
-    return almost_equal (x, rhs.x) &&
-           almost_equal (y, rhs.y) &&
-           almost_equal (z, rhs.z);
+util::vector<S>::operator== (const util::vector<S> &rhs) const {
+    for (size_t i = 0; i < S; ++i)
+        if (!almost_equal (this->data[i], rhs.data[i]))
+            return false;
+
+    return true;
 }
 
 
+template <size_t S>
 double
-vector::magnitude (void) const {
-    return sqrt (x * x + y * y + z * z);
+util::vector<S>::magnitude (void) const {
+    return sqrt (magnitude2 ());
 }
 
 
+template <size_t S>
 double
-vector::magnitude2 (void) const {
-    return x * x + y * y + z * z;
+util::vector<S>::magnitude2 (void) const {
+    double total = 0.0;
+    for (size_t i = 0; i < S; ++i)
+        total += pow2 (this->data[i]);
+    return total;
 }
 
 
+template <size_t S>
 double
-vector::dot (const vector &rhs) const {
-    return x * rhs.x + y * rhs.y + z * rhs.z;
+util::vector<S>::dot (const util::vector<S> &rhs) const {
+    double total = 0.0;
+    for (size_t i = 0; i < S; ++i)
+        total += this->data[i] + rhs.data[i];
+    return total;
 }
 
 
-vector
-vector::cross (const vector &rhs) const { 
-    return { y * rhs.z - z * rhs.y,
-             z * rhs.x - x * rhs.z,
-             x * rhs.y - y * rhs.x };
-}
-
-
-vector&
-vector::normalise (void) {
+template <size_t S>
+util::vector<S>&
+util::vector<S>::normalise (void) {
     double mag = magnitude ();
 
-    x /= mag;
-    y /= mag;
-    z /= mag;
+    for (size_t i = 0; i < S; ++i)
+        this->data[i] /= mag;
 
     return *this;
 }
 
 
-vector
-vector::normalised (void) const {
+template <size_t S>
+util::vector<S>
+util::vector<S>::normalised (void) const {
     double mag = magnitude ();
-    return { x / mag, y / mag, z / mag };
+    util::vector<S> out;
+    
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] / mag;
+
+    return out;
 }
 
 
-vector
-vector::spherical_to_cartesian (const vector &s) {
+util::vector<3>
+util::spherical_to_cartesian (const util::vector<3> &s) {
     return {
         s.x * sin (s.y) * cos (s.z),
         s.x * sin (s.y) * sin (s.z),
@@ -172,8 +224,8 @@ vector::spherical_to_cartesian (const vector &s) {
 }
 
 
-vector
-vector::cartesian_to_spherical (const vector &c) {
+util::vector<3>
+util::cartesian_to_spherical (const util::vector<3> &c) {
     double mag = c.magnitude ();
 
     return {
@@ -184,58 +236,81 @@ vector::cartesian_to_spherical (const vector &c) {
 }
 
 
+template <size_t S>
 bool
-vector::is_zero (void) const {
-    return almost_equal (x, 0.0) &&
-           almost_equal (y, 0.0) &&
-           almost_equal (z, 0.0);
+util::vector<S>::is_zero (void) const {
+    return std::all_of (begin (this->data),
+                        end   (this->data),
+                        [] (double i) { return almost_zero (i); });
 }
 
 
+template <size_t S>
 void
-vector::sanity (void) const {
-    CHECK_SOFT (!std::isnan (x));
-    CHECK_SOFT (!std::isnan (y));
-    CHECK_SOFT (!std::isnan (z));
+util::vector<S>::sanity (void) const {
+    CHECK_SOFT (std::all_of (begin (this->data),
+                             end   (this->data),
+                             [] (double i) { return !std::isnan (i); }));
 }
 
 
-util::vector
-util::operator* (double a, const util::vector &b)
+util::vector<3>
+util::cross (const util::vector<3> &a, const util::vector<3> &b) {
+    return { a.y * b.z - a.z * b.y,
+             a.z * b.x - a.x * b.z,
+             a.x * b.y - a.y * b.x };
+}
+
+
+template <size_t S>
+util::vector<S>
+util::operator* (double a, const util::vector<S> &b)
     { return b * a; }
 
 
+template util::vector<1> util::operator* (double, const util::vector<1>&);
+template util::vector<2> util::operator* (double, const util::vector<2>&);
+template util::vector<3> util::operator* (double, const util::vector<3>&);
+
+
+template <size_t S>
 std::ostream&
-util::operator<< (std::ostream &os, const util::vector &v) {
-    os << "vec(" << v.x << ", " << v.y << ", " << v.z << ")";
+util::operator<< (std::ostream &os, const util::vector<S> &v) {
+    os << "vec" << S << "(" << v.data[0];
+    for (double i: v.data)
+        os << ", " << i;
+    os << ")";
     return os;
 }
 
 
+template std::ostream& util::operator<< (std::ostream&, const util::vector<1> &v);
+template std::ostream& util::operator<< (std::ostream&, const util::vector<2> &v);
+template std::ostream& util::operator<< (std::ostream&, const util::vector<3> &v);
+
+
+template <size_t S>
 const json::node&
-util::operator>> (const json::node &node, util::vector &v) {
+util::operator>> (const json::node &node, util::vector<S> &v) {
     const json::array &array = node.as_array ();
+    if (array.size () != S) 
+        throw std::runtime_error ("Invalid dimensionality for json-to-vector");
 
-    switch (array.size ()) {
-        case 1:
-            v.x = array[0].as_number ();
-            v.y = std::numeric_limits<double>::quiet_NaN ();
-            v.z = std::numeric_limits<double>::quiet_NaN ();
-            return node;
-
-        case 2: v.y = array[1].as_number ();
-            v.x = array[0].as_number ();
-            v.y = array[1].as_number ();
-            v.z = std::numeric_limits<double>::quiet_NaN ();
-            return node;
-
-        case 3: v.z = array[2].as_number ();
-            v.x = array[0].as_number ();
-            v.y = array[1].as_number ();
-            v.z = array[2].as_number ();
-            return node;
-
-        default:
-            throw std::runtime_error ("Invalid dimensionality for json-to-vector");
-    }
+    std::transform (begin (array),
+                    end   (array),
+                    begin (v.data),
+                    [] (const json::node &n) {
+                        return n.as_number ().native ();
+                    });
+    return node;
 }
+
+
+template const json::node& util::operator>> (const json::node&, util::vector<1>&);
+template const json::node& util::operator>> (const json::node&, util::vector<2>&);
+template const json::node& util::operator>> (const json::node&, util::vector<3>&);
+
+
+template struct util::vector<1>;
+template struct util::vector<2>;
+template struct util::vector<3>;
diff --git a/vector.hpp b/vector.hpp
index 7e53550b..07631573 100644
--- a/vector.hpp
+++ b/vector.hpp
@@ -21,50 +21,70 @@
 #define __UTIL_VECTOR_HPP
 
 #include "json.hpp"
+#include "detail/coord.hpp"
 
+#include <array>
 #include <iostream>
+#include <initializer_list>
 
 namespace util {
-    struct vector {
-        double x, y, z;
+    template <size_t S>
+    struct vector : public detail::coord_data<S> {
+        static_assert (S > 0, "vector dimensions must be strictly positive");
 
-        vector  operator* (double) const;
-        vector& operator*=(double);
-        vector  operator* (const vector&) const;
-        vector& operator*=(const vector&);
+        vector ();
 
-        vector  operator+ (const vector&) const;
-        vector& operator+=(const vector&);
+        template <typename... T>
+        vector (T ...t): detail::coord_data<S> {std::forward<T> (t)...} { ; }
 
-        vector  operator- (void) const;
-        vector  operator- (const vector&) const;
-        vector& operator-=(const vector&);
+        util::vector<S>  operator* (double) const;
+        util::vector<S>& operator*=(double);
+        util::vector<S>  operator* (const util::vector<S>&) const;
+        util::vector<S>& operator*=(const util::vector<S>&);
 
-        vector& operator =(const vector &);
+        util::vector<S>  operator+ (const util::vector<S>&) const;
+        util::vector<S>& operator+=(const util::vector<S>&);
 
-        bool operator== (const vector &) const;
+        util::vector<S>  operator- (void) const;
+        util::vector<S>  operator- (const util::vector<S>&) const;
+        util::vector<S>& operator-=(const util::vector<S>&);
+
+        util::vector<S>& operator =(const util::vector <S>&);
+
+        bool operator== (const util::vector <S>&) const;
 
         double magnitude  (void) const;
         double magnitude2 (void) const;
 
-        double dot   (const vector&) const;
-        vector cross (const vector&) const;
+        double dot (const util::vector<S>&) const;
 
-        vector& normalise  (void);
-        vector  normalised (void) const;
+        util::vector<S>& normalise  (void);
+        util::vector<S>  normalised (void) const;
 
-        static vector spherical_to_cartesian (const vector &);
-        static vector cartesian_to_spherical (const vector &);
 
         bool is_zero (void) const;
 
         void sanity (void) const;
     };
 
-    util::vector operator* (double, const util::vector&);
+    vector<3> cross (const vector<3>&, const vector<3>&);
 
-    std::ostream& operator<< (std::ostream&, const util::vector&);
-    const json::node& operator>> (const json::node&, util::vector&);
+    vector<3> spherical_to_cartesian (const util::vector <3>&);
+    vector<3> cartesian_to_spherical (const util::vector <3>&);
+
+
+    typedef vector<2> vector2;
+    typedef vector<3> vector3;
+
+
+    template <size_t S>
+    util::vector<S> operator* (double, const util::vector<S>&);
+
+    template <size_t S>
+    std::ostream& operator<< (std::ostream&, const util::vector<S>&);
+
+    template <size_t S>
+    const json::node& operator>> (const json::node&, util::vector<S>&);
 
 }