Updated variable names in ef.py (#16)

- Updated variable names in ef.py (ad1fa7f216e5b9b49f922e4d5c01352c4808175f)


Co-authored-by: Vi Koi Nguyen <Yim-Koi@users.noreply.huggingface.co>

ef.py

@@ -77,8 +77,9 @@ def ef_viz(stock_df,choices):
     port_ef_df  = pd.DataFrame(data)
     #st.write(port_ef_df[tickers].T)
     ## NEEDS INPUT INSTEAD OF HARD CODE
-    a = 5 #the coefficient of risk aversion is A. If an invest is less risk averse A is small. We assume 25 < A < 35. 
-    rf = 0.041
+    #a = 5 #the coefficient of risk aversion is A. If an invest is less risk averse A is small. We assume 25 < A < 35. 
+    #rf = 0.041
+    
     min_vol_port = port_ef_df.iloc[port_ef_df['Volatility'].idxmin()]
     optimal_risky_port = port_ef_df.iloc[((port_ef_df['Returns']-rf)/port_ef_df['Volatility']).idxmax()]
     
@@ -92,7 +93,7 @@ def ef_viz(stock_df,choices):
 
     for er in np.linspace(rf, max(data['Returns']),20):
         sd = (er - rf)/ ((optimal_risky_port[0] - rf)/ optimal_risky_port[1])
-        u = er - 0.5*a*(sd**2)
+        u = er - 0.5*A_coef*(sd**2)
         cal_x.append(sd)
         cal_y.append(er)
         utl.append(u)