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Bug

Issue found in code when producing a confusion matrix for object detection. It seems like the FN was being added incorrectly to the matrix. Here is the code that was problematic for me. When removing the else condition, I was getting the correct TP value. It seems that num_classes, ends up being at the same position detection_classes[matched_detection_idx[j]]

for i, true_class_value in enumerate(true_classes):
    j = matched_true_idx == i
    print('sum(j)', sum(j))
    if matches.shape[0] > 0 and sum(j) == 1:
        result_matrix[
            true_class_value, detection_classes[matched_detection_idx[j]]
        ] += 1  # TP
    else:
        result_matrix[true_class_value, num_classes] += 1  # FN

Environment

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Minimal Reproducible Example

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Additional

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Are you willing to submit a PR?

• Yes I'd like to help by submitting a PR!