Implement scalar division for modules etc

Thi commit addresses #249.

nengo_spa/ast/dynamic.py

@@ -114,6 +114,13 @@ def __rmul__(self, other):
         else:
             return self._mul_with_dynamic(other, swap_inputs=True)
 
+    @binary_node_op
+    def __truediv__(self, other):
+        if isinstance(other, FixedScalar):
+            return self._mul_with_fixed(FixedScalar(1.0 / other.value))
+        else:
+            return NotImplemented
+
     @binary_node_op
     def dot(self, other):
         type_ = infer_types(self, other)

nengo_spa/ast/symbolic.py

@@ -114,6 +114,11 @@ def __rmul__(self, other):
         type_ = infer_types(self, other)
         return PointerSymbol(other.expr + "*" + self.expr, type_)
 
+    @symbolic_op
+    def __truediv__(self, other):
+        type_ = infer_types(self, other)
+        return PointerSymbol(self.expr + "/" + other.expr, type_)
+
     def dot(self, other):
         other = as_symbolic_node(other)
         if not isinstance(other, PointerSymbol):

nengo_spa/ast/tests/test_dynamic.py

@@ -70,6 +70,24 @@ def test_binary_operation_on_modules(Simulator, algebra, op, suffix, seed, rng):
     )
 
 
+@pytest.mark.parametrize("suffix", ["", ".output"])
+def test_division_with_fixed(Simulator, suffix, seed, rng):
+    vocab = spa.Vocabulary(16, pointer_gen=rng)
+    vocab.populate("A")
+
+    with spa.Network(seed=seed) as model:
+        a = spa.Transcode("A", output_vocab=vocab)  # noqa: F841
+        x = eval("a" + suffix + "/ 2")
+        p = nengo.Probe(x.construct(), synapse=0.03)
+
+    with Simulator(model) as sim:
+        sim.run(0.3)
+
+    assert_sp_close(
+        sim.trange(), sim.data[p], vocab.parse("0.5 * A"), skip=0.2, atol=0.3
+    )
+
+
 @pytest.mark.parametrize("op", ["+", "-", "*"])
 @pytest.mark.parametrize("order", ["AB", "BA"])
 def test_binary_operation_on_modules_with_pointer_symbol(

nengo_spa/ast/tests/test_symbolic.py

@@ -90,6 +90,17 @@ def test_multiply_fixed_scalar_and_pointer_symbol(scalar, rng):
     assert_equal(node.output, vocab.parse("2 * A").v)
 
 
+@pytest.mark.parametrize("scalar", [2, np.float64(2)])
+def test_divide_pointer_symbol_by_fixed_scalar(scalar, rng):
+    vocab = spa.Vocabulary(16, pointer_gen=rng)
+    vocab.populate("A")
+
+    with spa.Network():
+        x = PointerSymbol("A", TVocabulary(vocab)) / scalar
+        node = x.construct()
+    assert_equal(node.output, vocab.parse("0.5 * A").v)
+
+
 def test_fixed_dot(rng):
     vocab = spa.Vocabulary(16, pointer_gen=rng)
     vocab.populate("A; B")

nengo_spa/connectors.py

@@ -165,6 +165,7 @@ def op_impl(self, other):
     __rsub__ = __define_binary_op.__func__("__rsub__")
     __mul__ = __define_binary_op.__func__("__mul__")
     __rmul__ = __define_binary_op.__func__("__rmul__")
+    __truediv__ = __define_binary_op.__func__("__truediv__")
     __matmul__ = __define_binary_op.__func__("__matmul__")
     __rmatmul__ = __define_binary_op.__func__("__rmatmul__")