FowlkesMallows¶
Fowlkes-Mallows Index.
The Fowlkes-Mallows Index 1 2 is an external evaluation method that is used to determine the similarity between two clusterings, and also a metric to measure confusion matrices. The measure of similarity could be either between two hierarchical clusterings or a clustering and a benchmark classification. A higher value for the Fowlkes-Mallows index indicates a greater similarity between the clusters and the benchmark classifications.
The Fowlkes-Mallows Index, for two cluster algorithms, is defined as:
where
-
TP, FP, FN are respectively the number of true positives, false positives and false negatives;
-
TPR is the True Positive Rate (or Sensitivity/Recall), PPV is the Positive Predictive Rate (or Precision).
Parameters¶
-
cm
Default →
None
This parameter allows sharing the same confusion matrix between multiple metrics. Sharing a confusion matrix reduces the amount of storage and computation time.
Attributes¶
-
bigger_is_better
Indicate if a high value is better than a low one or not.
-
requires_labels
Indicates if labels are required, rather than probabilities.
-
works_with_weights
Indicate whether the model takes into consideration the effect of sample weights
Examples¶
from river import metrics
y_true = [0, 0, 0, 1, 1, 1]
y_pred = [0, 0, 1, 1, 2, 2]
metric = metrics.FowlkesMallows()
for yt, yp in zip(y_true, y_pred):
metric.update(yt, yp)
print(metric)
FowlkesMallows: 0.00%
FowlkesMallows: 100.00%
FowlkesMallows: 57.74%
FowlkesMallows: 40.82%
FowlkesMallows: 35.36%
FowlkesMallows: 47.14%
Methods¶
get
Return the current value of the metric.
is_better_than
Indicate if the current metric is better than another one.
Parameters
- other
revert
Revert the metric.
Parameters
- y_true
- y_pred
- w — defaults to
1.0
update
Update the metric.
Parameters
- y_true
- y_pred
- w — defaults to
1.0
works_with
Indicates whether or not a metric can work with a given model.
Parameters
- model — 'base.Estimator'
-
Wikipedia contributors. (2020, December 22). Fowlkes–Mallows index. In Wikipedia, The Free Encyclopedia, from https://en.wikipedia.org/w/index.php?title=Fowlkes%E2%80%93Mallows_index&oldid=995714222 ↩
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E. B. Fowkles and C. L. Mallows (1983). “A method for comparing two hierarchical clusterings”. Journal of the American Statistical Association ↩