Update app.py

app.py

@@ -19,7 +19,7 @@ def offset_calculation(prediction_length, rolling_windows, length):
     row_offset = -1 * prediction_length * rolling_windows
     if abs(row_offset) > 0.95 * length:
         raise gr.Error("Reduce prediction_length * rolling_windows")
-    return row_offset//2
+    return row_offset
 
 
 def preprocess(
@@ -85,7 +85,7 @@ def train_and_forecast(
     )
 
     test_data = test_gen.generate_instances(
-        prediction_length=prediction_length, windows=rolling_windows
+        prediction_length=prediction_length*2, windows=rolling_windows
     )
 
     evaluator = Evaluator(num_workers=0)