  void Compute(OpKernelContext* ctx) override {
    auto x = ctx->input(0);
    auto i = ctx->input(1);
    auto v = ctx->input(2);

    OP_REQUIRES(ctx, TensorShapeUtils::IsVector(i.shape()),
                errors::InvalidArgument("i must be a vector. ",
                                        i.shape().DebugString()));
    OP_REQUIRES(ctx, x.dims() == v.dims(),
                errors::InvalidArgument(
                    "x and v shape doesn't match (ranks differ): ",
                    x.shape().DebugString(), " vs. ", v.shape().DebugString()));
    for (int i = 1; i < x.dims(); ++i) {
      OP_REQUIRES(
          ctx, x.dim_size(i) == v.dim_size(i),
          errors::InvalidArgument("x and v shape doesn't match at index ", i,
                                  " : ", x.shape().DebugString(), " vs. ",
                                  v.shape().DebugString()));
    }
    OP_REQUIRES(ctx, i.dim_size(0) == v.dim_size(0),
                errors::InvalidArgument(
                    "i and x shape doesn't match at index 0: ",
                    i.shape().DebugString(), " vs. ", v.shape().DebugString()));

    Tensor y = x;  // This creates an alias intentionally.
    // Skip processing if tensors are empty.
    if (x.NumElements() > 0 && v.NumElements() > 0) {
      OP_REQUIRES_OK(ctx, DoCompute(ctx, i, v, &y));
    }
    ctx->set_output(0, y);
  }
Unknown