[TOPI] Average Pool2D Bug. (#3607)

* [TOPI] Average Pool2D Bug.

Issue - https://github.com/dmlc/tvm/issues/3581

* Add uint16 test.

tests/python/relay/test_op_level2.py

@@ -264,6 +264,25 @@ def _test_pool2d(opfunc, reffunc):
         op_res1 = intrp1.evaluate(func)(data)
         tvm.testing.assert_allclose(op_res1.asnumpy(), ref_res, rtol=1e-5, atol=1e-5)
 
+def _test_pool2d_int(opfunc, reffunc, dtype):
+    n, c, h, w = tvm.var("n"), 10, 224, 224
+    x = relay.var("x", relay.TensorType((n, c, h, w), dtype))
+    y = opfunc(x, pool_size=(1, 1))
+    assert "pool_size=" in y.astext()
+    yy = run_infer_type(y)
+    assert yy.checked_type == relay.TensorType((n, 10, 224, 224), dtype)
+    # test execution
+    dtype = "int32"
+    dshape = (1, 3, 28, 28)
+    x = relay.var("x", shape=dshape, dtype=dtype)
+    y = opfunc(x, pool_size=(2, 2), strides=(2, 2), padding=(0, 0))
+    func = relay.Function([x], y)
+    data = np.random.random_integers(low=-128, high=128, size=dshape)
+    ref_res = reffunc(data.reshape(1,3,14,2,14,2), axis=(3,5)).astype(dtype)
+    for target, ctx in ctx_list():
+        intrp1 = relay.create_executor("graph", ctx=ctx, target=target)
+        op_res1 = intrp1.evaluate(func)(data)
+        tvm.testing.assert_allclose(op_res1.asnumpy(), ref_res, rtol=1e-5, atol=1e-5)
 
 def _test_global_pool2d(opfunc, reffunc):
     n, c, h, w = tvm.var("n"), tvm.var("c"), 224, 224
@@ -294,6 +313,8 @@ def _test_global_pool2d(opfunc, reffunc):
 def test_pool2d():
     _test_pool2d(relay.nn.max_pool2d, np.max)
     _test_pool2d(relay.nn.avg_pool2d, np.mean)
+    _test_pool2d_int(relay.nn.avg_pool2d, np.mean, 'int32')
+    _test_pool2d_int(relay.nn.avg_pool2d, np.mean, 'uint16')
     _test_global_pool2d(relay.nn.global_max_pool2d, np.max)
     _test_global_pool2d(relay.nn.global_avg_pool2d, np.mean)
 

topi/include/topi/nn/pooling.h

@@ -130,19 +130,26 @@ inline Tensor pool_impl(const Tensor& x,
       return tvm::max(temp(indices), { dheight, dwidth });
     }, "tensor", "pool_max");
   } else if (pool_type == kAvgPool) {
+    // Pad the inputs
     auto temp = do_pad ? pad(x, pad_before, pad_after, 0, "pad_temp") : x;
-    auto tavg = [&](const Array<Var>& output, Expr divide_factor) {
+
+    // TVM compute for summing the pooling window.
+    auto pool_sum = tvm::compute(out_shape,
+    [&](const Array<Var>& output) {
       Array<Expr> indices;
       for (const Var& var : output) indices.push_back(var);
       indices.Set(height_axis, output[height_axis] * stride_height + dheight);
       indices.Set(width_axis, output[width_axis] * stride_width + dwidth);
-      return tvm::sum(temp(indices) / divide_factor, { dheight, dwidth });
-    };
+      return tvm::sum(temp(indices), { dheight, dwidth });
+    }, "tensor", "pool_sum");
 
+    // TVM compute for dividing the reduced window sum by kernel size.
     return tvm::compute(out_shape,
     [&](const Array<Var>& output) {
+      Array<Expr> indices;
+      for (const Var& var : output) indices.push_back(var);
       if (count_include_pad) {
-        return tavg(output, kernel_height * kernel_width);
+        return pool_sum(indices) / (kernel_height * kernel_width);
       } else {
         Expr h_start = output[height_axis] * stride_height - pad_top;
         Expr w_start = output[width_axis] * stride_width - pad_left;
@@ -152,9 +159,9 @@ inline Tensor pool_impl(const Tensor& x,
         w_start = ir::Max::make(w_start, make_const(Int(32), 0));
         Expr divide_factor = ir::Max::make((h_end - h_start) * (w_end - w_start),
                                            make_const(Int(32), 1));
-        return tavg(output, divide_factor);
+        return pool_sum(indices) / divide_factor;
       }
-    }, "tensor", "pool_avg");
+    }, "tensor", kElementWise);
   } else {
     LOG(ERROR) << "Unrecognized pool_type: " << pool_type;
     return x;