Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Proper management of the time-to-segment map when merging trajectories with 1-point segments #3248

Merged
merged 4 commits into from
Dec 24, 2021
Merged

Proper management of the time-to-segment map when merging trajectories with 1-point segments #3248

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
71f04ae
Proper management of segments_by_left_endpoints_ in Merge when a segm…
pleroy Dec 23, 2021
7dfde9c
Handle empty segments in consistency checks.
pleroy Dec 23, 2021
7a0cb0d
Typos.
pleroy Dec 23, 2021
fc5bca0
Cleanup.
pleroy Dec 23, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
32 changes: 22 additions & 10 deletions physics/discrete_trajectory_body.hpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -187,7 +187,7 @@ DiscreteTrajectory<Frame>::NewSegment() {
segment_by_left_endpoint_.end(), last_time, new_segment_sit);
}

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
return new_self;
}

Expand All @@ -205,7 +205,7 @@ DiscreteTrajectory<Frame>::DetachSegments(SegmentIterator const begin) {
/*to=*/detached,
/*to_segments_begin=*/detached.segments_->begin());

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
return detached;
}

Expand Down Expand Up @@ -245,7 +245,7 @@ DiscreteTrajectory<Frame>::AttachSegments(DiscreteTrajectory trajectory) {
/*to=*/*this,
/*to_segments_begin=*/end_before_splice);

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
return SegmentIterator(segments_.get(), end_before_splice);
}

Expand All @@ -270,7 +270,7 @@ void DiscreteTrajectory<Frame>::DeleteSegments(SegmentIterator& begin) {
// Make sure that the client doesn't try to use the invalid iterator.
begin = segments().end();

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
}

template<typename Frame>
Expand Down Expand Up @@ -300,7 +300,7 @@ void DiscreteTrajectory<Frame>::ForgetAfter(Instant const& t) {
segment_by_left_endpoint_.end());
}

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
}

template<typename Frame>
Expand Down Expand Up @@ -342,7 +342,7 @@ void DiscreteTrajectory<Frame>::ForgetBefore(Instant const& t) {
sit);
}

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
}

template<typename Frame>
Expand Down Expand Up @@ -396,12 +396,18 @@ void DiscreteTrajectory<Frame>::Merge(DiscreteTrajectory<Frame> trajectory) {
// Merge corresponding segments.
sit_t->Merge(std::move(*sit_s));

// If the left endpoint has changed, remove its entry from the time-to-
// segment map. Insert a new entry if the segment is not empty.
// If the left endpoint of |sit_t| has changed, remove its entry from the
// time-to-segment map, if any.
if (left_endpoint.has_value() &&
sit_t->front().time < left_endpoint.value()) {
segment_by_left_endpoint_.erase(left_endpoint.value());
auto const it = segment_by_left_endpoint_.find(left_endpoint.value());
if (it != segment_by_left_endpoint_.end() && it->second == sit_t) {
segment_by_left_endpoint_.erase(left_endpoint.value());
}
}
// Insert a new entry in the time-to-segment map if the segment is not
// empty. This entry will be overwritten by any future entry at the same
// time, thereby enforcing the invariants of the time-to-segment map.
if (!sit_t->empty()) {
segment_by_left_endpoint_.insert_or_assign(sit_t->front().time, sit_t);
}
Expand Down Expand Up @@ -431,7 +437,7 @@ void DiscreteTrajectory<Frame>::Merge(DiscreteTrajectory<Frame> trajectory) {
}
}

DCHECK_OK(ConsistencyStatus());
CHECK_OK(ConsistencyStatus());
}

template<typename Frame>
Expand Down Expand Up @@ -726,6 +732,12 @@ absl::Status DiscreteTrajectory<Frame>::ConsistencyStatus() const {
" and ", DebugString(sit2->front().time)));
}
}
if (sit1 != segments_->cend() && !sit1->empty()) {
return absl::InternalError(
absl::StrCat("Segment at time ", DebugString(sit1->front().time),
" missing in the time-to-segment map of size ",
segment_by_left_endpoint_.size()));
}
}
if (!segments_->empty()) {
int i = 0;
Expand Down
11 changes: 11 additions & 0 deletions physics/discrete_trajectory_test.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -628,6 +628,17 @@ TEST_F(DiscreteTrajectoryTest, Merge) {
EXPECT_EQ(t0_ + 9 * Second, sit->front().time);
EXPECT_EQ(t0_ + 14 * Second, sit->back().time);
}
{
auto trajectory1 = MakeTrajectory();
auto trajectory2 = MakeTrajectory();

trajectory1.ForgetAfter(t0_ + 9 * Second);
// This trajectory starts with a 1-point segment. Merge used to fail the
// consistency check because the time-to-segment map was losing an entry.
trajectory2.ForgetBefore(t0_ + 9 * Second);

trajectory2.Merge(std::move(trajectory1));
}
}

TEST_F(DiscreteTrajectoryTest, TMinTMaxEvaluate) {
Expand Down