class_docstr: Test class for `ErrorRelativeGlobalDimensionlessSynthesis` metric.
docstr: Test dtype support of the metric on GPU.
docstr_tok: ["Test","dtype","support","of","the","metric","on","GPU","."]
code: def test_ergas_half_gpu(self, reduction, preds, target, ratio):
      """Test dtype support of the metric on GPU."""
      self.run_precision_test_gpu(
          preds,
          target,
          ErrorRelativeGlobalDimensionlessSynthesis,
          error_relative_global_dimensionless_synthesis,
      )
  
imports: from functools import partial
  from typing import NamedTuple
  import pytest
  import torch
  from torch import Tensor
  from torchmetrics.functional.image.ergas import error_relative_global_dimensionless_synthesis
  from torchmetrics.image.ergas import ErrorRelativeGlobalDimensionlessSynthesis
  from torchmetrics.utilities.imports import _TORCH_GREATER_EQUAL_2_1
  from unittests import BATCH_SIZE, NUM_BATCHES
  from unittests.helpers import seed_all
  from unittests.helpers.testers import MetricTester
label_desc: Use image node_id 4 for calling the TestErrorRelativeGlobalDimensionlessSynthesis obj's underlying member method code with example usage: obj.test_ergas_half_gpu(reduction, preds, target, ratio) without return types