fixed unconditional sampling reproducibility issue

src/generate_unconditional_samples.py

@@ -17,9 +17,6 @@ def sample_model(
     temperature=1,
     top_k=0,
 ):
-    np.random.seed(seed)
-    tf.set_random_seed(seed)
-
     enc = encoder.get_encoder(model_name)
     hparams = model.default_hparams()
     with open(os.path.join('models', model_name, 'hparams.json')) as f:
@@ -31,6 +28,9 @@ def sample_model(
         raise ValueError("Can't get samples longer than window size: %s" % hparams.n_ctx)
 
     with tf.Session(graph=tf.Graph()) as sess:
+        np.random.seed(seed)
+        tf.set_random_seed(seed)
+
         output = sample.sample_sequence(
             hparams=hparams, length=length,
             start_token=enc.encoder['<|endoftext|>'],