feat(opr): let Argsort support empty IO

GitOrigin-RevId: 05fcac6e472e9d7e868516c210c96d8d2987b5dc

imperative/python/test/unit/functional/test_math.py

@@ -110,16 +110,42 @@ def test_sort():
     data2_shape = (12, 2)
     data1 = np.random.random(data1_shape).astype(np.float32)
     data2 = np.random.random(data2_shape).astype(np.float32)
-    output0 = [np.sort(data1), np.argsort(data1).astype(np.int32)]
-    output1 = [np.sort(data2), np.argsort(data2).astype(np.int32)]
+    output1 = [np.sort(data1), np.argsort(data1).astype(np.int32)]
+    output2 = [np.sort(data2), np.argsort(data2).astype(np.int32)]
 
     cases = [
-        {"input": data1, "output": output0},
-        {"input": data2, "output": output1},
+        {"input": data1, "output": output1},
+        {"input": data2, "output": output2},
     ]
     opr_test(cases, F.sort)
 
 
+@pytest.mark.parametrize("is_symbolic", [None, False, True])
+def test_sort_empty(is_symbolic):
+    data_shapes = [
+        (0,),
+        (10, 0),
+    ]
+
+    def fn(x):
+        return F.sort(x)
+
+    for shape in data_shapes:
+        if is_symbolic is not None:
+            fn_ = jit.trace(symbolic=is_symbolic)(fn)
+        else:
+            fn_ = fn
+        data = np.random.random(shape).astype(np.float32)
+        for _ in range(3):
+            outs = fn_(tensor(data))
+            ref_outs = (np.sort(data), np.argsort(data))
+            assert len(ref_outs) == len(outs)
+            for i in range(len(outs)):
+                np.testing.assert_equal(outs[i].numpy(), ref_outs[i])
+        if is_symbolic is None:
+            break
+
+
 def test_normalize():
 
     cases = [

src/opr/impl/misc.cpp

@@ -75,7 +75,16 @@ MEGDNN_OPR_INIT1(Argmin, "argmin")
 /* ================= ArgsortForward =================  */
 
 MGB_DYN_TYPE_OBJ_FINAL_IMPL(ArgsortForward);
-MEGDNN_OPR_CTOR_INIT1(ArgsortForward, "argsort")
+// MEGDNN_OPR_CTOR_INIT1(ArgsortForward, "argsort")
+
+ArgsortForward::ArgsortForward(VarNode *i0, const Param &param, const OperatorNodeConfig &config):
+        Super(OperatorNodeBaseCtorParam{ i0->owner_graph(), config, "argsort", {i0}} ) {
+    init_megdnn_opr(*this, param);
+    add_input({i0});
+    output(0)->add_flag(VarNode::Flag::ALLOW_EMPTY_SHAPE);  // sorted value
+    output(1)->add_flag(VarNode::Flag::ALLOW_EMPTY_SHAPE);  // sorted index
+    intl::MegDNNOprInitPostCtor<ArgsortForward>::apply(*this);
+}
 
 std::array<SymbolVar, 2> ArgsortForward::make(
         SymbolVar in_tensor, const Param &param,
@@ -87,6 +96,32 @@ std::array<SymbolVar, 2> ArgsortForward::make(
     return {node->output(0), node->output(1)};
 }
 
+void ArgsortForward::scn_do_execute() {
+    if (input(0)->dev_tensor().empty()) {
+        mgb_assert(output(0)->dev_tensor().empty() &&
+                   output(1)->dev_tensor().empty());
+        return;
+    }
+    mgb_assert(!output(0)->dev_tensor().empty() &&
+               !output(1)->dev_tensor().empty());
+    Super::scn_do_execute();
+}
+
+void ArgsortForward::get_output_var_shape(
+        const TensorShapeArray &inp_shape,
+        TensorShapeArray &out_shape) const {
+    mgb_assert(inp_shape.size() == 1 && out_shape.size() == 2);
+    out_shape[0] = inp_shape[0];
+    out_shape[1] = inp_shape[0];
+}
+
+ArgsortForward::NodeProp* ArgsortForward::do_make_node_prop() const {
+    auto ret = Super::do_make_node_prop();
+    ret->add_dep_type_existing_var(input(0),
+                                   NodeProp::DepType::VALUE_ALLOW_EMPTY);
+    return ret;
+}
+
 #if MGB_ENABLE_GRAD
 MGB_IMPL_OPR_GRAD(ArgsortForward) {
     mgb_assert(out_grad.size() == 3 && wrt_idx == 0 && !out_grad[2]);

src/opr/include/megbrain/opr/misc.h

@@ -55,6 +55,12 @@ MGB_DEFINE_OPR_CLASS(Argmin,
  */
 MGB_DEFINE_OPR_CLASS(ArgsortForward,
             intl::MegDNNOprWrapperFwd<megdnn::ArgsortForward>) // {
+    protected:
+        NodeProp* do_make_node_prop() const override;
+        void scn_do_execute() override;
+        void get_output_var_shape(
+                const TensorShapeArray &inp_shape,
+                TensorShapeArray &out_shape) const override;
     public:
         ArgsortForward(VarNode *in_tensor,
                 const Param &param,