Fixes issue #156414: Fixes bug in implementation of _combine_histogram (Follow up) (#2418)

Fixes issue #156414: Fixes bug in implementation of _combine_histograms in torchao/.

Author: Akabbaj

torchao/quantization/pt2e/observer.py

@@ -1248,7 +1248,7 @@ def _combine_histograms(
         # If the orig hist only has one value (i.e., the min and max are the same)
         # we can just add it into new histogram
         if orig_min == orig_max:
-            bin_value = torch.sum(update_hist)
+            bin_value = torch.sum(orig_hist)
             transformed_orig_hist = (
                 torch.histc(orig_min, bins=self.bins, min=update_min, max=update_max)  # type: ignore[arg-type]
                 * bin_value