Fix compatibility for binary operations

AUTHORS

@@ -22,4 +22,5 @@ Contributors:
 * Lily Wang <lilyminium>
 * Josh Vermaas <jvermaas>
 * Irfan Alibay <IAlibay>
-* Zhiyi Wu <xiki-tempula>
+* Zhiyi Wu <xiki-tempula>
+* Olivier Languin-Cattoën <ollyfutur>

CHANGELOG

@@ -13,14 +13,26 @@ The rules for this file:
   * accompany each entry with github issue/PR number (Issue #xyz)
 
 ------------------------------------------------------------------------------
-??/??/???? IAlibay
-  * 1.0.3
+??/??/???? IAlibay, ollyfutur
+  * 1.1.0
 
   Changes
 
   * Python 3.13 and 3.14 are now supported (PR #140)
   * Support for Python 3.9 and 3.10 is now dropped as per SPEC0 (PR #140)
 
+  Enhancements
+
+  * `Grid` now accepts binary operations with any operand that can be 
+    broadcasted to the grid's shape according to `numpy` broadcasting rules
+    (PR #142)
+
+  Fixes
+
+  * Attempting binary operations on grids with different edges now raises an
+    exception (PR #142)
+
+
 10/21/2023 IAlibay, orbeckst, lilyminium
 
   * 1.0.2

gridData/core.py

@@ -711,7 +711,7 @@ def check_compatible(self, other):
 
         `other` is compatible if
 
-        1) `other` is a scalar
+        1) `other` is a scalar or an array-like broadcastable to the grid
         2) `other` is a grid defined on the same edges
 
         In order to make `other` compatible, resample it on the same
@@ -732,13 +732,22 @@ def check_compatible(self, other):
         --------
         :meth:`resample`
         """
-
-        if not (numpy.isreal(other) or self == other):
+        if isinstance(other, Grid):
+            is_compatible = all(
+                numpy.allclose(other_edge, self_edge)
+                for other_edge, self_edge in zip(other.edges, self.edges)
+            )
+        else:
+            try:
+                is_compatible = numpy.broadcast(self.grid, other).shape == self.grid.shape
+            except ValueError:
+                is_compatible = False
+        if not is_compatible:
             raise TypeError(
                 "The argument cannot be arithmetically combined with the grid. "
-                "It must be a scalar or a grid with identical edges. "
-                "Use Grid.resample(other.edges) to make a new grid that is "
-                "compatible with other.")
+                "It must be broadcastable to the grid's shape or a `Grid` with identical edges. "
+                "Use `Grid.resample(other.edges)` to make a new grid that is "
+                "compatible with `other`.")
         return True
 
     def _interpolationFunctionFactory(self, spline_order=None, cval=None):

gridData/tests/test_grid.py

@@ -107,12 +107,18 @@ def test_power(self, data):
     def test_compatibility_type(self, data):
         assert data['grid'].check_compatible(data['grid'])
         assert data['grid'].check_compatible(3)
-        g = Grid(data['griddata'], origin=data['origin'] - 1, delta=data['delta'])
+        g = Grid(data['griddata'], origin=data['origin'], delta=data['delta'])
         assert data['grid'].check_compatible(g)
+        assert data['grid'].check_compatible(g.grid)
 
     def test_wrong_compatibile_type(self, data):
+        g = Grid(data['griddata'], origin=data['origin'] + 1, delta=data['delta'])
+        with pytest.raises(TypeError):
+            data['grid'].check_compatible(g)
+
+        arr = np.zeros(data['griddata'].shape[-1] + 1)  # Not broadcastable
         with pytest.raises(TypeError):
-            data['grid'].check_compatible("foo")
+            data['grid'].check_compatible(arr)
 
     def test_non_orthonormal_boxes(self, data):
         delta = np.eye(3)