add eval functions

[ysli16]

Add common functions to evaluate the performance of ego vehicle in the simulation. For safety, the functions to find the minimum distance, minimum time-to-collision(ttc) and maximum deceleration-rate-to-avoid-collision(drac) are implemented. The vehicle geometry is considered in the computation. For efficiency, the function to find the first time that the ego vehicle entered its desired lane is implemented. It only checks whether the vehicle enters the goal lane(or its predecessor/successor), regardless of the progress on the lane. For comfort, the max jerk and the rms of frequency-weighted acceleration(according to ISO2631) is computed.

This will be merged after tested locally for the pdm4ar exercise.

[alezana]

@ysli16 could you please

• [x] rename the folder to eval or metrics and remove the evaluate_ prefix in the file names (makes import lines less redundant and cleaner)
• [x] consider adding some unit tests as for example done for the sequences: https://github.com/idsc-frazzoli/dg-commons/blob/master/src/dg_commons_tests/test_sequence.py or https://github.com/idsc-frazzoli/dg-commons/blob/master/src/dg_commons_tests/test_seq_op.py

[alezana]

Other suggestions from looking at the code:

• [x] max jerk can be rewritten in a more compact way with iterate with dt
• [x] use list/tuple comprehension if you can (more compact and usually slightly more efficient) E.g.

  acc_time = []
  for idx in range(len(commands.timestamps)):
      acc_time.append(commands.values[idx].acc)

  can be a single line acc_time = [v.acc for v in commands.values]

• [x] avoid ranges to iterate over iterables if you then need to extract values (more error prone and less elegant) E.g.

  for idx in range(0, len(states.values)):
      state = states.values[idx]
      timestep = states.timestamps[idx]
      reached = desired_lane_reached(lanelet_network, goal_lane, state, pos_tol, heading_tol)
      if reached:
          reached_time = timestep
          break
  return float(reached_time)

  can be

  for idx, state in enumerate(states.values):
      reached = desired_lane_reached(lanelet_network, goal_lane, state, pos_tol, heading_tol)
      if reached:
          reached_time = states.timestamps[idx]
          break
  return float(reached_time)

  ps: Here I don't really like the -1 as return if it is not reached, very bug prone

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.37500% with 40 lines in your changes missing coverage. Please review.

Project coverage is 80.22%. Comparing base (c217817) to head (330ec2c).

Files with missing lines	Patch %	Lines
src/dg_commons/eval/efficiency.py	62.66%	19 Missing and 9 partials :warning:
src/dg_commons/eval/safety.py	94.59%	3 Missing and 5 partials :warning:
src/dg_commons/eval/comfort.py	87.87%	2 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #124 +/- ## ========================================== + Coverage 78.31% 80.22% +1.91% ========================================== Files 72 75 +3 Lines 4943 5199 +256 Branches 331 377 +46 ========================================== + Hits 3871 4171 +300 + Misses 991 930 -61 - Partials 81 98 +17 ```

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[alezana]

@ysli16 see the above comment as review