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from sklearn.neighbors import KNeighborsClassifier | |
from sklearn.model_selection import train_test_split | |
from sklearn.metrics import accuracy_score | |
from .base_model import BaseModel | |
from ..config import HEART_DISEASE_MODEL_PATH, RANDOM_STATE, TEST_SIZE | |
import numpy as np | |
import pandas as pd | |
class HeartDiseaseModel(BaseModel): | |
def __init__(self): | |
super().__init__(HEART_DISEASE_MODEL_PATH) | |
self.model = KNeighborsClassifier( | |
n_neighbors=5, | |
weights='distance', # Weight by distance for better local sensitivity | |
metric='manhattan' # Manhattan distance for better feature importance | |
) | |
self.feature_names = [ | |
'age', 'sex', 'cp', 'trestbps', 'chol', 'fbs', 'restecg', | |
'thalach', 'exang', 'oldpeak', 'slope', 'ca', 'thal' | |
] | |
self.X_train = None | |
self.y_train = None | |
# Define risk thresholds | |
self.high_risk_threshold = 0.5 | |
# Feature importance weights | |
self.feature_weights = { | |
'age': 1.5, # Age is important | |
'cp': 2.0, # Chest pain type is very important | |
'trestbps': 1.2, # Blood pressure | |
'chol': 1.2, # Cholesterol | |
'thalach': 1.5, # Max heart rate | |
'oldpeak': 1.8, # ST depression | |
'ca': 2.0, # Number of vessels | |
'thal': 1.5 # Thalassemia | |
} | |
def train(self, X, y): | |
X = X[self.feature_names] | |
# Apply feature weights | |
for feature, weight in self.feature_weights.items(): | |
if feature in X.columns: | |
X[feature] = X[feature] * weight | |
X_train, X_test, y_train, y_test = train_test_split( | |
X, y, test_size=TEST_SIZE, random_state=RANDOM_STATE, | |
stratify=y # Ensure balanced split | |
) | |
self.X_train = X_train | |
self.y_train = y_train | |
self.model.fit(X_train, y_train) | |
return self.evaluate(X_train, X_test, y_train, y_test) | |
def predict(self, X): | |
if self.scaler: | |
X = self.scaler.transform(X) | |
X = pd.DataFrame(X, columns=self.feature_names) | |
# Apply feature weights | |
for feature, weight in self.feature_weights.items(): | |
if feature in X.columns: | |
X[feature] = X[feature] * weight | |
# Get nearest neighbors | |
distances, indices = self.model.kneighbors(X) | |
# Get similar cases | |
similar_cases = self.X_train.iloc[indices[0]] | |
similar_outcomes = self.y_train.iloc[indices[0]] | |
# Calculate risk score based on weighted voting | |
weights = 1 / (distances[0] + 1e-6) | |
weighted_prob = np.sum(similar_outcomes * weights) / np.sum(weights) | |
# Calculate additional risk factors | |
risk_factors = [] | |
# Convert X back to original scale if scaler exists | |
if self.scaler: | |
X_orig = pd.DataFrame(self.scaler.inverse_transform(X), columns=self.feature_names) | |
else: | |
X_orig = X | |
# Check various risk factors | |
if X_orig['age'].iloc[0] > 60: | |
weighted_prob += 0.1 | |
if X_orig['cp'].iloc[0] >= 2: # Non-typical chest pain | |
weighted_prob += 0.1 | |
if X_orig['trestbps'].iloc[0] > 140: # High blood pressure | |
weighted_prob += 0.1 | |
if X_orig['chol'].iloc[0] > 240: # High cholesterol | |
weighted_prob += 0.1 | |
if X_orig['thalach'].iloc[0] < 120: # Low max heart rate | |
weighted_prob += 0.1 | |
if X_orig['oldpeak'].iloc[0] > 2: # High ST depression | |
weighted_prob += 0.15 | |
if X_orig['ca'].iloc[0] > 0: # Presence of vessels colored by fluoroscopy | |
weighted_prob += 0.15 * X_orig['ca'].iloc[0] | |
# Make final prediction based on threshold | |
prediction = np.array([1 if weighted_prob >= self.high_risk_threshold else 0]) | |
return prediction, similar_cases, similar_outcomes, distances[0] | |
def evaluate(self, X_train, X_test, y_train, y_test): | |
train_accuracy = accuracy_score(y_train, self.model.predict(X_train)) | |
test_accuracy = accuracy_score(y_test, self.model.predict(X_test)) | |
return train_accuracy, test_accuracy |