Implement metrics comparison table & plotting

[LinasKo]

The metrics system allows the users to compute a metrics result - a class with values for a specific metrics run.

When comparing multiple models, a natural next step is to aggregate the results into a single table and/or plot them on a single chart.

Let's make this step easy!

I propose two new functions:

def aggregate_metric_results(metrics_results: List[MetricResult], *,  include_object_sizes=False) -> pd.DataFrame:
   """
   Raises when different types of metrics results are passed in
   """

def plot_aggregate_metric_results(metrics_results: List[MetricResult], *, include_object_sizes=False) -> None:
    ...


class MetricResult(ABC):
   @abstractmethod
   def to_pandas():
      raise NotImplementedError()

   def plot():
      raise NotImplementedError()

---

Several questions we need to address:

1. Would it be better for plot_aggregate_metric_results to take in a pd.DataFrame? This way, the user can apply their own sorting or preprocessing, but we're not guaranteed to have the fields we need.
2. Could the naming be improved?

---

Suggested by @David-rn, discussion

[LinasKo]

Note: Please share a Google Colab with minimal code to test the new feature. We know it's additional work, but it will speed up the review process. You may use the Starter Template. The reviewer must test each change. Setting up a local environment to do this is time-consuming. Please ensure that Google Colab can be accessed without any issues (make it public). Thank you! :pray:

[David-rn]

Regarding the first question and considering the guide that led to this discussion, I think that maybe it is a better option using a List[MetricResult] as input as first suggested, since the user would already have used supervision classes (Detections, MetricResult).

If you think it's a good idea, I can give it a try these days and share a Colab to evaluate whether it is feasible or there are more things to consider.

[LinasKo]

That'd be most helpful @David-rn ! I'm assigning it to you.

[David-rn]

I have written both functions and I came across some things:

1. The function aggregate_metric_results is straightforward, since the metrics returns a DataFrame, which can be aggregated. In case you need to check the implementation, it can be seen here. Maybe it is needed to decide on the exceptions, naming, etc.
2. The second function, plot_aggregate_metric_results, is not that easy/clean to implement. Unlike the to_pandas method that returns an object, plot function shows the actual plot. For this reason, I have added a parameter to this function (return_params=False) to get the necessary values to plot the results of several models in the same plot. It can be seen here. I have only added the parameter in the class MeanAveragePrecision to showcase the situation and check with you what would be the best decision.

A Colab Notebook is shared here.

[LinasKo]

Hey David,

1. The one quick edit I'd make is moving the new method to utils.
2. I was imagining an aggregate method with more if-else cases, but your approach seems better. How about we add a result._get_plot_details() to each metric result? The _ will hide it from docs, even if a docstring is added. Then, both plot() and plot_aggregate_metric_results can use it (yes, I know it's slightly idiosyncratic, as an external method accesses a private one).

Preview for any other reviewers stumbling upon this.

It's looking great so far!

[David-rn]

Hi @LinasKo, thanks for the comments!

1. Just to make sure, do you mean to move the file with both methods into utils? Or, do you mean to add both methods into the utils.py file inside the utils module? I'm guessing the first one.
2. Perfect! I'll add the method _get_plot_details() into the new MetricResult class.

[LinasKo]

1. Either option seems fine. A separate file is slightly tidier, I reckon.