more cleanly fall back to random captions

utils/sample_generator.py

@@ -142,7 +142,7 @@ class SampleGenerator:
             self.show_progress_bars = config.get('show_progress_bars', self.show_progress_bars)
             sample_requests_json = config.get('samples', None)
             if sample_requests_json is None:
-                self.sample_requests = self._make_random_caption_sample_requests()
+                self.sample_requests = []
             else:
                 default_seed = config.get('seed', self.default_seed)
                 default_size = (self.default_resolution, self.default_resolution)
@@ -152,16 +152,14 @@ class SampleGenerator:
                                                       size=tuple(p.get('size', default_size)),
                                                       wants_random_caption=p.get('random_caption', False)
                                                       ) for p in sample_requests_json]
+            if len(self.sample_requests) == 0:
+                self._make_random_caption_sample_requests()
 
     @torch.no_grad()
     def generate_samples(self, pipe: StableDiffusionPipeline, global_step: int):
         """
         generates samples at different cfg scales and saves them to disk
         """
-        if len(self.sample_requests) == 0:
-            raise NotImplementedError("todo: implement random captions")
-            #max_prompts = min(4, len(batch["captions"]))
-            #sample_requests = batch["captions"][:max_prompts]
         logging.info(f"Generating samples gs:{global_step}, for {[p.prompt for p in self.sample_requests]}")
 
         pipe.set_progress_bar_config(disable=(not self.show_progress_bars))