only execute kernels if size(dim) > 0

torch_scatter/div.py

@@ -89,4 +89,6 @@ def scatter_div(src, index, dim=-1, out=None, dim_size=None, fill_value=1):
                [0.5000, 0.2500, 0.5000, 1.0000, 1.0000, 1.0000]])
     """
     src, out, index, dim = gen(src, index, dim, out, dim_size, fill_value)
+    if src.size(dim) == 0:  # pragma: no cover
+        return out
     return ScatterDiv.apply(out, src, index, dim)

torch_scatter/max.py

@@ -96,4 +96,6 @@ def scatter_max(src, index, dim=-1, out=None, dim_size=None, fill_value=0):
                [ 1,  4,  3, -1, -1, -1]])
     """
     src, out, index, dim = gen(src, index, dim, out, dim_size, fill_value)
+    if src.size(dim) == 0:  # pragma: no cover
+        return out
     return ScatterMax.apply(out, src, index, dim)

torch_scatter/min.py

@@ -96,4 +96,6 @@ def scatter_min(src, index, dim=-1, out=None, dim_size=None, fill_value=0):
                [ 1,  4,  3, -1, -1, -1]])
     """
     src, out, index, dim = gen(src, index, dim, out, dim_size, fill_value)
+    if src.size(dim) == 0:  # pragma: no cover
+        return out
     return ScatterMin.apply(out, src, index, dim)

torch_scatter/mul.py

@@ -88,4 +88,6 @@ def scatter_mul(src, index, dim=-1, out=None, dim_size=None, fill_value=1):
                [6, 4, 8, 1, 1, 1]])
     """
     src, out, index, dim = gen(src, index, dim, out, dim_size, fill_value)
+    if src.size(dim) == 0:  # pragma: no cover
+        return out
     return ScatterMul.apply(out, src, index, dim)