fix up indexing of summed_mask in shapesys, staterror (#333)

The main difficulty with shapesys/staterror as it affects multiple (non-consecutive) bins is the way we do masking. For situations where we need to figure out whether to enable the mask or not, it was filling in -1 when the parameter index was 0 which is not good. Additionally, tensorflow.gather() is not happy with -1.
scikit-hep · Oct 21, 2018 · 0fdfcc3 · 0fdfcc3
1 parent ea52590
commit 0fdfcc3
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Showing 2 changed files with 7 additions and 7 deletions.
diff --git a/pyhf/modifiers/shapesys.py b/pyhf/modifiers/shapesys.py
@@ -58,11 +58,7 @@ def __init__(self,shapesys_mods,pdfconfig,mega_mods):
                 zero_mask = summed_mask == 0
                 # then apply the mask
                 summed_mask[positive_mask] = inds
-                summed_mask[zero_mask] = -1
-                # nb: old code above was
-                #     summed_mask[summed_mask > 0] = inds
-                #     summed_mask[summed_mask == 0] = -1
-                # This code broke when the `inds` included a '0' because it would replace that value with -1.
+                summed_mask[zero_mask] = 0
                 access_rows.append(summed_mask.tolist())
             self._factor_access_indices = default_backend.tolist(default_backend.stack(access_rows))
             self.finalize(pdfconfig)

diff --git a/pyhf/modifiers/staterror.py b/pyhf/modifiers/staterror.py
@@ -50,8 +50,12 @@ def __init__(self,staterr_mods,pdfconfig,mega_mods):
             for mask,inds in zip(staterror_mask, self._staterror_indices):
                 summed_mask = default_backend.sum(mask[:,0,:],axis=0)
                 assert default_backend.shape(summed_mask[summed_mask >  0]) == default_backend.shape(default_backend.astensor(inds))
-                summed_mask[summed_mask >  0] = inds
-                summed_mask[summed_mask == 0] = -1
+                # make masks of > 0 and == 0
+                positive_mask = summed_mask > 0
+                zero_mask = summed_mask == 0
+                # then apply the mask
+                summed_mask[positive_mask] = inds
+                summed_mask[zero_mask] = 0
                 access_rows.append(summed_mask.tolist())
             self._factor_access_indices = default_backend.tolist(default_backend.stack(access_rows))
             self.finalize(pdfconfig)