Add cpp tests

test/csrc/ops/test_softmax.cpp

@@ -0,0 +1,61 @@
+#include <ATen/ATen.h>
+#include <gtest/gtest.h>
+
+#include <utility>
+
+#include "pyg_lib/csrc/ops/softmax.h"
+
+using namespace at::indexing;
+
+at::Tensor softmax2D_ref_impl(const at::Tensor& src,
+                              const at::Tensor& ptr,
+                              const int64_t dim) {
+  auto out = at::zeros_like(src);
+
+  for (int64_t i = 0; i < src.size(1 - dim); ++i) {
+    for (int64_t j = 0; j < ptr.size(0) - 1; ++j) {
+      const auto beg = ptr[j].item<int64_t>();
+      const auto end = ptr[j + 1].item<int64_t>();
+      const auto row_slice = (dim == 0) ? Slice(beg, end) : Slice(i, i + 1);
+      const auto col_slice = (dim == 0) ? Slice(i, i + 1) : Slice(beg, end);
+      out.index_put_({row_slice, col_slice},
+                     src.index({row_slice, col_slice}).softmax(dim));
+    }
+  }
+
+  return out;
+}
+
+class CPUTest : public testing::TestWithParam<int64_t> {};
+
+TEST_P(CPUTest, SoftmaxCSRForward) {
+  const auto dim = ::testing::TestWithParam<int64_t>::GetParam();
+  const auto src = at::rand({8, 8});
+  const auto ptr = at::tensor({0, 3, 4, 7, 8}, at::kLong);
+  const auto expected_out = softmax2D_ref_impl(src, ptr, dim);
+
+  const auto out = pyg::ops::softmax_csr_forward(src, ptr, dim);
+  EXPECT_EQ(expected_out.size(0), out.size(0));
+  EXPECT_EQ(expected_out.size(1), out.size(1));
+  EXPECT_TRUE(at::allclose(expected_out, out, 1e-04, 1e-04));
+}
+
+TEST_P(CPUTest, SoftmaxCSRBackward) {
+  const auto dim = ::testing::TestWithParam<int64_t>::GetParam();
+  const auto src = at::rand({8, 8});
+  src.set_requires_grad(true);
+  const auto ptr = at::tensor({0, 3, 4, 7, 8}, at::kLong);
+  const auto out = softmax2D_ref_impl(src, ptr, dim);
+  const auto out_grad = at::rand({8, 8});
+
+  const auto in_grad = pyg::ops::softmax_csr_backward(out, out_grad, ptr, dim);
+  out.backward(out_grad);
+  EXPECT_EQ(src.grad().size(0), in_grad.size(0));
+  EXPECT_EQ(src.grad().size(1), in_grad.size(1));
+  EXPECT_TRUE(at::allclose(src.grad(), in_grad, 1e-04, 1e-04));
+}
+
+INSTANTIATE_TEST_SUITE_P(OpsTest,
+                         CPUTest,
+                         // dim
+                         testing::Values(0, 1));