code: def test_ard_batch(self):
      a = torch.tensor(
          [[[1, 2, 3], [2, 4, 0]], [[-1, 1, 2], [2, 1, 4]]],
          dtype=torch.float,
      )
      b = torch.tensor(
          [[[1, 3, 1]], [[2, -1, 0]]], dtype=torch.float
      ).repeat(1, 2, 1)
      lengthscales = torch.tensor([[[1, 2, 1]]], dtype=torch.float)
  
      kernel = RQKernel(batch_shape=torch.Size([2]), ard_num_dims=3)
      kernel.initialize(lengthscale=lengthscales)
      kernel.initialize(alpha=3.0)
      kernel.eval()
  
      scaled_a = a.div(lengthscales)
      scaled_b = b.div(lengthscales)
      dist = (
          (scaled_a.unsqueeze(-2) - scaled_b.unsqueeze(-3))
          .pow(2)
          .sum(dim=-1)
      )
      actual = dist.div_(2 * kernel.alpha).add_(1.0).pow(-kernel.alpha)
      res = kernel(a, b).to_dense()
      self.assertLess(torch.norm(res - actual), 1e-5)
  
      # diag
      res = kernel(a, b).diagonal(dim1=-1, dim2=-2)
      actual = actual.diagonal(dim1=-1, dim2=-2)
      self.assertLess(torch.norm(res - actual), 1e-5)
  
      # # batch_dims
      double_batch_a = scaled_a.transpose(-1, -2).unsqueeze(-1)
      double_batch_b = scaled_b.transpose(-1, -2).unsqueeze(-2)
      actual = double_batch_a - double_batch_b
      alpha = kernel.alpha.view(2, 1, 1, 1)
      actual = actual.pow_(2).div_(2 * alpha).add_(1.0).pow(-alpha)
      res = kernel(a, b, last_dim_is_batch=True).to_dense()
      self.assertLess(torch.norm(res - actual), 1e-5)
  
      # batch_dims and diag
      res = kernel(a, b, last_dim_is_batch=True).diagonal(
          dim1=-1, dim2=-2
      )
      actual = actual.diagonal(dim1=-2, dim2=-1)
      self.assertLess(torch.norm(res - actual), 1e-5)
  
file_path: gpytorch/test/kernels/test_rq_kernel.py
imports: import math
  import unittest
  import torch
  from gpytorch.kernels import RQKernel
  from gpytorch.test.base_kernel_test_case import BaseKernelTestCase
label_desc: Use image node_id 4 for calling the TestRQKernel obj's underlying member method code with example usage: obj.test_ard_batch() without return types