[Bug]: - Causal fidelity problem with steps=-1

[AntoninPoche]

Module

Metrics

Current Behavior

When using a causal fidelity metric (either Insertion or Deletion) and setting steps=-1, the method returns an Attribute error.

Expected Behavior

I expect the method to support parameter values indicated in the documentation.

To solve it, in fidelity.py:
Change L306: tf.math.floor(self.nb_features * max_percentage_perturbed)
By: int(np.floor(self.nb_features * max_percentage_perturbed))

Version

1.3.1

Environment

No response

Relevant log output

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-8-ebb4e1c3761e> in <cell line: 7>()
      6 i = 0
      7 for explanation_name, explanations in explanations_to_test.items():
----> 8   deletion_score = metric(explanations)
      9   deletion_scores.append((explanation_name, deletion_score))
     10 

5 frames
/usr/local/lib/python3.10/dist-packages/xplique/metrics/base.py in __call__(self, explanations)
    157                  explanations: Union[tf.Tensor, np.array]) -> float:
    158         """Evaluate alias"""
--> 159         return self.evaluate(explanations)

/usr/local/lib/python3.10/dist-packages/xplique/metrics/fidelity.py in evaluate(self, explanations)
    326             better) curve.
    327         """
--> 328         scores_dict = self.detailed_evaluate(explanations)
    329 
    330         # compute auc using trapezoidal rule (the steps are equally distributed)

/usr/local/lib/python3.10/dist-packages/xplique/metrics/fidelity.py in detailed_evaluate(self, explanations)
    379         baselines_flatten = baselines.reshape(self.inputs_flatten.shape)
    380 
--> 381         steps = np.linspace(0, self.max_nb_perturbed, self.steps + 1, dtype=np.int32)
    382 
    383         if self.causal_mode == "deletion":

/usr/local/lib/python3.10/dist-packages/numpy/core/overrides.py in linspace(*args, **kwargs)

/usr/local/lib/python3.10/dist-packages/numpy/core/function_base.py in linspace(start, stop, num, endpoint, retstep, dtype, axis)
    118 
    119     """
--> 120     num = operator.index(num)
    121     if num < 0:
    122         raise ValueError("Number of samples, %s, must be non-negative." % num)

/usr/local/lib/python3.10/dist-packages/tensorflow/python/framework/ops.py in __index__(self)
    297 
    298   def __index__(self):
--> 299     return self._numpy().__index__()
    300 
    301   def __bool__(self) -> bool:

AttributeError: 'numpy.float64' object has no attribute '__index__'

To Reproduce

Initialize Insertion or Deletion with steps=-1 and call either evaluate or detailed_evaluate. It can easily be done in the Metrics: Getting started tuto.