feat(mge/imperative): add permutation support for the tensor

GitOrigin-RevId: 7ed0447bfe18d7744fa7771191313d6b45ec8522

imperative/python/megengine/random/rng.py

@@ -225,7 +225,7 @@ def _shuffle(inp: Tensor, seed: int, handle: int) -> Tensor:
     assert inp.size > 0, "size needs to be greater than 0"
     op = ShuffleRNG(seed=seed, handle=handle)
     output, _ = apply(op, inp)
-    inp._reset(output)
+    return output
 
 
 class RNG:
@@ -554,12 +554,15 @@ class RNG:
         _seed = self._seed() if callable(self._seed) else self._seed
         return _poisson(lam=lam, size=size, seed=_seed, handle=self._handle)
 
-    def permutation(self, n: int, *, dtype: str = "int32"):
-        r"""Generates a random permutation of integers from :math:`0` to :math:`n - 1`.
+    def permutation(self, n: Union[int, Tensor], *, dtype: str = "int32"):
+        r"""Randomly permute a sequence, or return a permuted range.
+            If ``n`` is a multi-dimensional tensor, it is only shuffled along its first index.
 
         Args:
-            n: the upper bound. Must be larger than 0.
-            dtype: the output data type. int32, int16 and float32 are supported. Default: int32
+            n: If ``n`` is an integer, random permutation of integers from :math:`0` to :math:`n - 1`. 
+                If ``n`` is an tensor, make a copy and shuffle the elements randomly.
+            dtype: the output data type when ``n`` is an integer.
+                int32, int16 and float32 are supported. Default: int32
 
         Returns:
             the output tensor.
@@ -568,13 +571,18 @@ class RNG:
 
             .. testcode::
 
+                import numpy as np
                 import megengine as mge
                 import megengine.random as rand
 
-                x = rand.permutation(n=10, dtype="int32")
+                x = rand.permutation(10, dtype="int32")
+                print(x.numpy())
+
+                x = rand.permutation(10, dtype="float32")
                 print(x.numpy())
 
-                x = rand.permutation(n=10, dtype="float32")
+                x = mge.tensor(np.arange(18)).reshape(6,3)
+                x = rand.permutation(x)
                 print(x.numpy())
 
             Outputs:
@@ -584,11 +592,20 @@ class RNG:
 
                 [4 5 0 7 3 8 6 1 9 2]
                 [3. 4. 9. 0. 6. 8. 7. 1. 5. 2.]
+                [[12 13 14]
+                 [ 3  4  5]
+                 [15 16 17]
+                 [ 0  1  2]
+                 [ 9 10 11]
+                 [ 6  7  8]]
         """
         _seed = self._seed() if callable(self._seed) else self._seed
-        return _permutation(
-            n=n, seed=_seed, device=self._device, handle=self._handle, dtype=dtype
-        )
+        if isinstance(n, int):
+            return _permutation(
+                n=n, seed=_seed, device=self._device, handle=self._handle, dtype=dtype
+            )
+        assert isinstance(n, Tensor)
+        return _shuffle(inp=n, seed=_seed, handle=self._handle)
 
     def shuffle(self, inp: Tensor):
         r"""Modify a sequence in-place by shuffling its contents. 
@@ -627,7 +644,7 @@ class RNG:
                  [ 6.  7.  8.]]
         """
         _seed = self._seed() if callable(self._seed) else self._seed
-        _shuffle(inp=inp, seed=_seed, handle=self._handle)
+        inp._reset(_shuffle(inp=inp, seed=_seed, handle=self._handle))
 
     def __del__(self):
         if self._handle != 0:

imperative/python/test/unit/random/test_rng.py

@@ -28,6 +28,7 @@ from megengine.core.ops.builtin import (
     UniformRNG,
 )
 from megengine.device import get_device_count
+from megengine.jit import trace
 from megengine.random import RNG
 from megengine.random import seed as set_global_seed
 from megengine.random import uniform
@@ -370,21 +371,22 @@ def test_PoissonRNG():
 @pytest.mark.skipif(
     get_device_count("xpu") <= 1, reason="xpu counts need > 1",
 )
-def test_PermutationRNG():
+@pytest.mark.parametrize("symbolic", [True, False])
+def test_PermutationRNG(symbolic):
     m1 = RNG(seed=111, device="xpu0")
     m2 = RNG(seed=111, device="xpu1")
     m3 = RNG(seed=222, device="xpu0")
-    out1 = m1.permutation(n=1000)
+    out1 = m1.permutation(1000)
     out1_ = m1.uniform(size=(1000,))
-    out2 = m2.permutation(n=1000)
-    out3 = m3.permutation(n=1000)
+    out2 = m2.permutation(1000)
+    out3 = m3.permutation(1000)
 
     np.testing.assert_equal(out1.numpy(), out2.numpy())
     assert out1.device == "xpu0" and out2.device == "xpu1"
     assert not (out1.numpy() == out3.numpy()).all()
     assert not (out1.numpy() == out1_.numpy()).all()
 
-    out = m1.permutation(n=1000)
+    out = m1.permutation(1000)
     out_shp = out.shape
     if isinstance(out_shp, tuple):
         assert out_shp == (1000,)
@@ -397,6 +399,24 @@ def test_PermutationRNG():
     assert sum_result(out, lambda x: x) < 500
     assert sum_result(out, np.sort) == 1000
 
+    def func():
+        out = m1.permutation(Tensor(7))
+        out_shp = out.shape
+        if isinstance(out_shp, tuple):
+            assert out_shp == (1,)
+        else:
+            assert all(out.shape.numpy() == np.array([1]))
+        n, m = 6, 3
+        out = m1.permutation(Tensor(np.arange(n * m), dtype="float32").reshape(n, m))
+        out_shp = out.shape
+        if isinstance(out_shp, tuple):
+            assert out_shp == (n, m)
+        else:
+            assert all(out.shape.numpy() == np.array([n, m]))
+
+    func = trace(symbolic=symbolic)(func)
+    func()
+
 
 @pytest.mark.skipif(
     get_device_count("xpu") <= 1, reason="xpu counts need > 1",

src/opr/impl/rand.cpp

@@ -214,8 +214,12 @@ ShuffleRNGForward::ShuffleRNGForward(VarNode* data, const Param& param,
                                      const OperatorNodeConfig& config)
         : Super({data->owner_graph(), config, "shuffle_rng", {data}}, param) {
     add_input({data});
-    add_output(None)->dtype(data->dtype());
-    add_output(None)->dtype(dtype::Int32{});
+    add_output(None)
+            ->dtype(data->dtype())
+            .add_flag(VarNode::Flag::ALLOW_EMPTY_SHAPE);
+    add_output(None)
+            ->dtype(dtype::Int32{})
+            .add_flag(VarNode::Flag::ALLOW_EMPTY_SHAPE);
     cg::add_workspace_output(this);
     add_equivalence_component<ScalarHash<void*>>(this);
 }
@@ -266,12 +270,27 @@ void ShuffleRNGForward::add_input_layout_constraint() {
 };
 
 void ShuffleRNGForward::scn_do_execute() {
+    auto&& ret = output(0);
+    if (ret->layout().is_empty()) {
+        mgb_assert(ret->dev_tensor().empty());
+        return;
+    }
     m_dnn_opr->exec(input(0)->dev_tensor().as_megdnn(),
                     output(0)->dev_tensor().as_megdnn(),
                     output(1)->dev_tensor().as_megdnn(),
                     get_megdnn_workspace_from_var(output(2)));
 }
 
+cg::OperatorNodeBase::NodeProp* ShuffleRNGForward::do_make_node_prop() const {
+    auto prop = Super::do_make_node_prop();
+    prop->add_flag(NodeProp::Flag::IMPURE_FUNC);
+    for (auto i : input()) {
+        prop->add_dep_type_existing_var(i,
+                                        NodeProp::DepType::VALUE_ALLOW_EMPTY);
+    }
+    return prop;
+}
+
 #if MGB_ENABLE_GRAD
 MGB_IMPL_OPR_GRAD(ShuffleRNGForward) {
     mgb_assert(out_grad.size() == 3 && wrt_idx == 0 && !out_grad[2]);