Adds a validity check for Sessions created using the TimeVaryingVolumetricGrid

include/gz/math/TimeVaryingVolumetricGrid.hh

@@ -41,6 +41,14 @@ class TimeVaryingVolumetricGrid
  /// \brief Creates a session. Call this before querying the interface.
  public: S CreateSession() const;
 
+ /// \brief Creates a session at a given time.
+ /// Call this before querying the interface.
+ /// \param[in] _time - The time at which to create the session.
+ public: S CreateSession(const T &_time) const;
+
+ /// \brief Returns true if a session is valid. False if invalid,
+ public: bool IsValid(const S &_session) const;
+
  /// \brief Steps the session to a fixed time step
  /// \param[in] _session - The session to be stepped
  /// \param[in] _time - The time at which the session should be set.
@@ -54,7 +62,7 @@ class TimeVaryingVolumetricGrid
  public: std::optional<V> LookUp(const S &_session, const Vector3<P> &_pos)
  const;
 
- /// \brief Get the bounds of this grid field at given time.
+ /// \brief Get the spatial bounds of this grid field at given time.
  /// \return A pair of vectors. All zeros if session is invalid.
  public: std::pair<Vector3<V>, Vector3<V>> Bounds(const S &_session) const;
 };
@@ -71,6 +79,18 @@ class TimeVaryingVolumetricGrid<T, V, InMemorySession<T, P>, P>
  return indices.CreateSession();
  }
 
+ /// \brief Documentation Inherited
+ public: InMemorySession<T, V> CreateSession(const T &_time) const
+ {
+ return indices.CreateSession(_time);
+ }
+
+ /// \brief Documentation Inherited
+ public: bool IsValid(const InMemorySession<T, P> &_session) const
+ {
+ return indices.IsValid(_session);
+ }
+
  /// \brief Documentation Inherited
  public: std::optional<InMemorySession<T, P>>
  StepTo(const InMemorySession<T, double> &_session, const T &_time) const

include/gz/math/TimeVaryingVolumetricGridLookupField.hh

@@ -142,6 +142,11 @@ namespace gz
  return sess;
  }
 
+ /// \brief In memory session
+ public: bool IsValid(const InMemorySession<T, V> &_session) const {
+ return this->gridFields.end() != _session.iter;
+ }
+
  /// \brief Documentation inherited
  public: std::optional<InMemorySession<T, V>> StepTo(
  const InMemorySession<T, V> &_session, const T &_time) const {

src/TimeVaryingVolumetricGridLookupField_TEST.cc

@@ -44,6 +44,10 @@ TEST(TimeVaryingVolumetricLookupFieldTest, TestConstruction)
  {
  // Get data at T=0
  auto session = timeVaryingField.CreateSession();
+
+ // Check session validity
+ ASSERT_TRUE(timeVaryingField.IsValid(session));
+
  auto points = timeVaryingField.LookUp(session, Vector3d{0.5, 0.5, 0.5});
  ASSERT_EQ(points.size(), 2);
  ASSERT_EQ(points[0].time, 0);
@@ -100,6 +104,10 @@ TEST(TimeVaryingVolumetricLookupFieldTest, TestConstruction)
 
  // Create invalid session
  auto invalid_session = timeVaryingField.CreateSession(500);
+
+ // Check session validity
+ ASSERT_FALSE(timeVaryingField.IsValid(invalid_session));
+
  points = timeVaryingField.LookUp(
  invalid_session, Vector3d{0.5, 0.5, 0.5});
  ASSERT_EQ(points.size(), 0);

src/TimeVaryingVolumetricGrid_TEST.cc

@@ -40,6 +40,9 @@ TEST(TimeVaryingVolumetricGridTest, TestConstruction)
  auto grid = gridFactory.Build();
  auto session = grid.CreateSession();
 
+ // Check validity
+ ASSERT_TRUE(grid.IsValid(session));
+
  // Check stepping
  auto val = grid.LookUp(session, Vector3d{0.5, 0.5, 0.5});
  ASSERT_TRUE(val.has_value());
@@ -114,4 +117,8 @@ TEST(TimeVaryingVolumetricGridTest, TestEmptyGrid)
  ASSERT_NEAR(max.X(), 0, 1e-6);
  ASSERT_NEAR(max.Y(), 0, 1e-6);
  ASSERT_NEAR(max.Z(), 0, 1e-6);
+
+ auto invalid_session = grid.CreateSession(500);
+ // Check validity
+ ASSERT_FALSE(grid.IsValid(invalid_session));
 }