Update app.py

app.py

@@ -57,6 +57,7 @@ llm = Llama(
 )
 
 DEFAULT_SYSTEM_PROMPT = """You are FinChat, a knowledgeable AI assistant specializing in investing and finance. Provide accurate, helpful, reasoned, detailed, and comprehensive answers to investing questions. Always base responses on reliable information and advise users to consult professionals for personalized advice.
+Always respond exclusively in English. Do not use any other language in your responses.
 
 Example:
 User: average return for TSLA between 2010 and 2020
@@ -85,8 +86,7 @@ def generate(
         # Parse tickers: split by comma, strip spaces, handle "and"
         tickers = [t.strip().upper() for t in re.split(r',|\band\b', tickers_str) if t.strip()]
         responses = []
-        years = int(end_year) - int(start_year)
-        if years <= 0:
+        if int(end_year) <= int(start_year):
             yield "The specified time period is invalid (end year must be after start year)."
             return
         for ticker in tickers:
@@ -98,13 +98,20 @@ def generate(
                         data = data.droplevel('Ticker', axis=1)
                     initial = data['Adj Close'].iloc[0]
                     final = data['Adj Close'].iloc[-1]
-                    cagr = ((final / initial) ** (1 / years) - 1) * 100
-                    responses.append(f"{ticker}: approximately {cagr:.2f}%")
+                    start_date = data.index[0]
+                    end_date = data.index[-1]
+                    days = (end_date - start_date).days
+                    years = days / 365.25
+                    if years > 0:
+                        cagr = ((final / initial) ** (1 / years) - 1) * 100
+                        responses.append(f"{ticker}: approximately {cagr:.2f}%")
+                    else:
+                        responses.append(f"{ticker}: Invalid period (no elapsed time).")
                 else:
                     responses.append(f"{ticker}: No historical data available between {start_year} and {end_year}.")
             except Exception as e:
                 responses.append(f"{ticker}: Error calculating CAGR - {str(e)}")
-        full_response = "The compound annual growth rates (CAGR) for the requested stocks from {} to {} are:\n".format(start_year, end_year)
+        full_response = f"The compound annual growth rates (CAGR) for the requested stocks from {start_year} to {end_year} are:\n"
         full_response += "\n".join(responses)
         full_response += "\nThese represent the average annual returns over that period, accounting for compounding. Note that past performance is not indicative of future results, and I recommend consulting a financial advisor for personalized advice."
         yield full_response