more flexible shapeblending

python/damask/util.py

@@ -512,7 +512,8 @@ def shapeshifter(fro: _Tuple[int, ...],
     return tuple(final_shape[::-1] if mode == 'left' else final_shape)
 
 def shapeblender(a: _Tuple[int, ...],
-                 b: _Tuple[int, ...]) -> _Tuple[int, ...]:
+                 b: _Tuple[int, ...],
+                 keep_ones: bool = True) -> _Tuple[int, ...]:
     """
     Return a shape that overlaps the rightmost entries of 'a' with the leftmost of 'b'.
 
@@ -522,6 +523,9 @@ def shapeblender(a: _Tuple[int, ...],
         Shape of first array.
     b : tuple
         Shape of second array.
+    keep_ones : bool, optional
+        Treat innermost '1's as literal value instead of dimensional placeholder.
+        Defaults to True.
 
     Examples
     --------
@@ -531,13 +535,30 @@ def shapeblender(a: _Tuple[int, ...],
         (1,2,3)
     >>> shapeblender((1,),(2,2,1))
         (1,2,2,1)
+    >>> shapeblender((1,),(2,2,1),False)
+        (2,2,1)
     >>> shapeblender((3,2),(3,2))
         (3,2)
 
     """
-    i = min(len(a),len(b))
-    while i > 0 and a[-i:] != b[:i]: i -= 1
-    return a + b[i:]
+    def is_broadcastable(a,b):
+        try:
+            _np.broadcast_shapes(a,b)
+            return True
+        except ValueError:
+            return False
+
+    a_,_b = a,b
+    if keep_ones:
+        i = min(len(a_),len(_b))
+        while i > 0 and a_[-i:] != _b[:i]: i -= 1
+        return a_ + _b[i:]
+    else:
+        a_ += max(0,len(_b)-len(a_))*(1,)
+        while not is_broadcastable(a_,_b):
+            a_ = a_ + ((1,) if len(a_)<=len(_b) else ())
+            _b = ((1,) if len(_b)<len(a_) else ()) + _b
+        return _np.broadcast_shapes(a_,_b)
 
 
 def _docstringer(docstring: _Union[str, _Callable],

python/tests/test_util.py

@@ -128,18 +128,22 @@ class TestUtil:
         with pytest.raises(ValueError):
             util.shapeshifter(fro,to,mode)
 
-    @pytest.mark.parametrize('a,b,answer',
+    @pytest.mark.parametrize('a,b,ones,answer',
                              [
-                              ((),(1,),(1,)),
-                              ((1,),(),(1,)),
-                              ((1,),(7,),(1,7)),
-                              ((2,),(2,2),(2,2)),
-                              ((1,2),(2,2),(1,2,2)),
-                              ((1,2,3),(2,3,4),(1,2,3,4)),
-                              ((1,2,3),(1,2,3),(1,2,3)),
+                              ((),(1,),True,(1,)),
+                              ((1,),(),False,(1,)),
+                              ((1,1),(7,),False,(1,7)),
+                              ((1,),(7,),False,(7,)),
+                              ((1,),(7,),True,(1,7)),
+                              ((2,),(2,2),False,(2,2)),
+                              ((1,2),(2,2),False,(2,2)),
+                              ((1,1,2),(2,2),False,(1,2,2)),
+                              ((1,1,2),(2,2),True,(1,1,2,2)),
+                              ((1,2,3),(2,3,4),False,(1,2,3,4)),
+                              ((1,2,3),(1,2,3),False,(1,2,3)),
                              ])
-    def test_shapeblender(self,a,b,answer):
-        assert util.shapeblender(a,b) == answer
+    def test_shapeblender(self,a,b,ones,answer):
+        assert util.shapeblender(a,b,ones) == answer
 
     @pytest.mark.parametrize('style',[util.emph,util.deemph,util.warn,util.strikeout])
     def test_decorate(self,style):