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4c01182 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | import sys
import numpy as np
from src.core.logger import logging
from src.core.exception import AppException
from src.app.monitoring.service_metrics import EXPLAINER_REQUEST_SUCCESS, EXPLAINER_REQUEST_FAILED
class ExplainerService:
def __init__(self, explainer, model_booster, vectorizer):
"""
Initializes an instance of LimeExplainer explaination service.
Args:
explainer (LimeTextExplainer) : An instance of LimeTextExplainer.
model_booster (xgb.XGBClassifier) : An instance of the XGBoost model.
vectorizer : An instance of the vectorizer to transform input text into numerical features.
"""
self.explainer = explainer
self.booster = model_booster
self.vectorizer = vectorizer
def _get_prediction(self, text) -> np.ndarray:
"""
Internal function to get class probability scores for lime explainer.
"""
X = self.vectorizer.transform(text)
prob = self.booster.inplace_predict(X)
if len(prob.shape) == 1:
prob = np.vstack([1 - prob, prob]).T
return prob
def explain(self, text: str):
"""
Generate an explanation of the prediction made by the model for a given text.
Returns:
HTML content of the explanation which is rendered in the UI
"""
try:
explanation = self.explainer.explain_instance(
text,
self._get_prediction,
num_features=10,
num_samples=20
)
html_content = explanation.as_html()
EXPLAINER_REQUEST_SUCCESS.inc()
return html_content
except Exception as e:
EXPLAINER_REQUEST_FAILED.inc()
logging.error(f"Explainer service failed: {e}", exc_info=True)
raise AppException(e, sys) |