Add Vector4 functions to match Vector3 (#132)

This implements the functions Min(), Min(Vector4), Max() and Max(Vector4) in Vector4 API, similar to the existing same functions in Vector3.

Signed-off-by: Lucas Fernando <[email protected]>

include/ignition/math/Vector4.hh

@@ -17,6 +17,8 @@
 #ifndef IGNITION_MATH_VECTOR4_HH_
 #define IGNITION_MATH_VECTOR4_HH_
 
+#include <algorithm>
+
 #include <ignition/math/Matrix4.hh>
 #include <ignition/math/Helpers.hh>
 #include <ignition/math/config.hh>
@@ -126,6 +128,42 @@ namespace ignition
         this->data[3] = _w;
       }
 
+      /// \brief Set this vector's components to the maximum of itself and the
+      ///        passed in vector
+      /// \param[in] _v the maximum clamping vector
+      public: void Max(const Vector4<T> &_v)
+      {
+        this->data[0] = std::max(_v[0], this->data[0]);
+        this->data[1] = std::max(_v[1], this->data[1]);
+        this->data[2] = std::max(_v[2], this->data[2]);
+        this->data[3] = std::max(_v[3], this->data[3]);
+      }
+
+      /// \brief Set this vector's components to the minimum of itself and the
+      ///        passed in vector
+      /// \param[in] _v the minimum clamping vector
+      public: void Min(const Vector4<T> &_v)
+      {
+        this->data[0] = std::min(_v[0], this->data[0]);
+        this->data[1] = std::min(_v[1], this->data[1]);
+        this->data[2] = std::min(_v[2], this->data[2]);
+        this->data[3] = std::min(_v[3], this->data[3]);
+      }
+
+      /// \brief Get the maximum value in the vector
+      /// \return the maximum element
+      public: T Max() const
+      {
+        return *std::max_element(this->data, this->data+4);
+      }
+
+      /// \brief Get the minimum value in the vector
+      /// \return the minimum element
+      public: T Min() const
+      {
+        return *std::min_element(this->data, this->data+4);
+      }
+
       /// \brief Assignment operator
       /// \param[in] _v the vector
       /// \return a reference to this vector

src/Vector4_TEST.cc

@@ -156,6 +156,38 @@ TEST(Vector4dTest, NoException)
   EXPECT_DOUBLE_EQ(v[4], 4.0);
 }
 
+/////////////////////////////////////////////////
+TEST(Vector4dTest, Max)
+{
+  math::Vector4d vec1(0.1, 0.2, 0.3, 0.2);
+  math::Vector4d vec2(0.2, 0.3, 0.4, 0.3);
+  math::Vector4d vec3(0.1, 0.2, 0.3, 0.4);
+
+  EXPECT_DOUBLE_EQ(vec1.Max(), 0.3);
+
+  vec1.Max(vec2);
+  EXPECT_EQ(vec1, math::Vector4d(0.2, 0.3, 0.4, 0.3));
+
+  vec1.Max(vec3);
+  EXPECT_EQ(vec1, math::Vector4d(0.2, 0.3, 0.4, 0.4));
+}
+
+/////////////////////////////////////////////////
+TEST(Vector4dTest, Min)
+{
+  math::Vector4d vec1(0.1, 0.2, 0.3, 0.4);
+  math::Vector4d vec2(0.2, 0.3, 0.4, 0.3);
+  math::Vector4d vec3(0.05, 0.1, 0.2, 0.2);
+
+  EXPECT_DOUBLE_EQ(vec1.Min(), 0.1);
+
+  vec1.Min(vec2);
+  EXPECT_EQ(vec1, math::Vector4d(0.1, 0.2, 0.3, 0.3));
+
+  vec1.Min(vec3);
+  EXPECT_EQ(vec1, math::Vector4d(0.05, 0.1, 0.2, 0.2));
+}
+
 /////////////////////////////////////////////////
 // Test Equal function with specified tolerance
 TEST(Vector2Test, EqualTolerance)