# What does this PR do?
1. Fixes an issue explained in https://github.com/pytorch/pytorch/issues/105840 when using FSDP for training very large models. Should be merged after https://github.com/huggingface/accelerate/pull/1777

Currently, when using FSDP, the model is loaded for each of the N processes completely on CPU leading to huge CPU RAM usage. When training models like Flacon-40B with FSDP on a dgx node with 8 GPUs, it would lead to CPU RAM getting out of memory because each process is loading 160GB (40B x 4Bytes (FP32)) in CPU RAM for a total of 160*8=1280GB requirement which results in script getting killed due to out of CPU RAM.

To combat this, we load the model only on rank 0 and have it on meta device when rank!=0. Then use no-op param_init_fn along with sync_module_states=True for FSDP to properly init the weights on other ranks and broadcast the params from rank 0 to other ranks. 

Usage:

**No user-facing changes**:

Post this PR:
```
accelerator.process_index=0 GPU Memory before entering the loading : 0
accelerator.process_index=0 GPU Memory consumed at the end of the loading (end-begin): 0
accelerator.process_index=0 GPU Peak Memory consumed during the loading (max-begin): 0
accelerator.process_index=0 GPU Total Peak Memory consumed during the loading (max): 0
accelerator.process_index=0 CPU Memory before entering the loading : 926
accelerator.process_index=0 CPU Memory consumed at the end of the loading (end-begin): 26415
accelerator.process_index=0 CPU Peak Memory consumed during the loading (max-begin): 31818
accelerator.process_index=0 CPU Total Peak Memory consumed during the loading (max): 32744
accelerator.process_index=0 model.lm_head.weight=Parameter containing:
tensor([[-0.0179,  0.0201, -0.0273,  ..., -0.0275, -0.0396, -0.0131],
        [-0.0510, -0.0079, -0.0383,  ..., -0.0481,  0.0581,  0.0282],
        [-0.0217, -0.0216, -0.0064,  ..., -0.0508,  0.0554, -0.0013],
        ...,
        [ 0.0425,  0.0452, -0.0131,  ...,  0.0019,  0.0476,  0.0342],
        [-0.0170, -0.0085,  0.0449,  ..., -0.0074,  0.0178,  0.0043],
        [-0.0439, -0.0859, -0.0820,  ...,  0.0130,  0.0669,  0.0884]],
       requires_grad=True)
accelerator.process_index=1 GPU Memory before entering the loading : 0
accelerator.process_index=1 GPU Memory consumed at the end of the loading (end-begin): 0
accelerator.process_index=1 GPU Peak Memory consumed during the loading (max-begin): 0
accelerator.process_index=1 GPU Total Peak Memory consumed during the loading (max): 0
accelerator.process_index=1 CPU Memory before entering the loading : 933
accelerator.process_index=1 CPU Memory consumed at the end of the loading (end-begin): 10
accelerator.process_index=1 CPU Peak Memory consumed during the loading (max-begin): 573
accelerator.process_index=1 CPU Total Peak Memory consumed during the loading (max): 1506
accelerator.process_index=1 model.lm_head.weight=Parameter containing:
tensor([[0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.],
        ...,
        [0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.]], requires_grad=True)
accelerator.process_index=0 GPU Memory before entering the prepare : 0
accelerator.process_index=0 GPU Memory consumed at the end of the prepare (end-begin): 13202
accelerator.process_index=0 GPU Peak Memory consumed during the prepare (max-begin): 15458
accelerator.process_index=0 GPU Total Peak Memory consumed during the prepare (max): 15458
accelerator.process_index=0 CPU Memory before entering the prepare : 27345
accelerator.process_index=0 CPU Memory consumed at the end of the prepare (end-begin): -26394
accelerator.process_index=0 CPU Peak Memory consumed during the prepare (max-begin): 0
accelerator.process_index=0 CPU Total Peak Memory consumed during the prepare (max): 27345
FullyShardedDataParallel(
  (_fsdp_wrapped_module): RWForCausalLM(
    (transformer): RWModel(
      (word_embeddings): Embedding(65024, 4544)
      (h): ModuleList(
        (0-31): 32 x FullyShardedDataParallel(
          (_fsdp_wrapped_module): DecoderLayer(
            (input_layernorm): LayerNorm((4544,), eps=1e-05, elementwise_affine=True)
            (self_attention): Attention(
              (maybe_rotary): RotaryEmbedding()
              (query_key_value): Linear(in_features=4544, out_features=4672, bias=False)
              (dense): Linear(in_features=4544, out_features=4544, bias=False)
              (attention_dropout): Dropout(p=0.0, inplace=False)
            )
            (mlp): MLP(
              (dense_h_to_4h): Linear(in_features=4544, out_features=18176, bias=False)
              (act): GELU(approximate='none')
              (dense_4h_to_h): Linear(in_features=18176, out_features=4544, bias=False)
            )
          )
        )
      )
      (ln_f): LayerNorm((4544,), eps=1e-05, elementwise_affine=True)
    )
    (lm_head): Linear(in_features=4544, out_features=65024, bias=False)
  )
)
accelerator.process_index=1 GPU Memory before entering the prepare : 0
accelerator.process_index=1 GPU Memory consumed at the end of the prepare (end-begin): 13202
accelerator.process_index=1 GPU Peak Memory consumed during the prepare (max-begin): 15458
accelerator.process_index=1 GPU Total Peak Memory consumed during the prepare (max): 15458
accelerator.process_index=1 CPU Memory before entering the prepare : 945
accelerator.process_index=1 CPU Memory consumed at the end of the prepare (end-begin): 4
accelerator.process_index=1 CPU Peak Memory consumed during the prepare (max-begin): 4
accelerator.process_index=1 CPU Total Peak Memory consumed during the prepare (max): 949
accelerator.process_index=1 model.lm_head.weight=Parameter containing:
tensor([[-0.0179,  0.0201, -0.0273,  ..., -0.0275, -0.0396, -0.0131],
        [-0.0510, -0.0079, -0.0383,  ..., -0.0481,  0.0581,  0.0282],
        [-0.0217, -0.0216, -0.0064,  ..., -0.0508,  0.0554, -0.0013],
        ...,
        [ 0.0425,  0.0452, -0.0131,  ...,  0.0019,  0.0476,  0.0342],
        [-0.0170, -0.0085,  0.0449,  ..., -0.0074,  0.0178,  0.0043],
        [-0.0439, -0.0859, -0.0820,  ...,  0.0130,  0.0669,  0.0884]],
       device='cuda:1', requires_grad=True)
accelerator.process_index=0 model.lm_head.weight=Parameter containing:
tensor([[-0.0179,  0.0201, -0.0273,  ..., -0.0275, -0.0396, -0.0131],
        [-0.0510, -0.0079, -0.0383,  ..., -0.0481,  0.0581,  0.0282],
        [-0.0217, -0.0216, -0.0064,  ..., -0.0508,  0.0554, -0.0013],
        ...,
        [ 0.0425,  0.0452, -0.0131,  ...,  0.0019,  0.0476,  0.0342],
        [-0.0170, -0.0085,  0.0449,  ..., -0.0074,  0.0178,  0.0043],
        [-0.0439, -0.0859, -0.0820,  ...,  0.0130,  0.0669,  0.0884]],
       device='cuda:0', requires_grad=True)
```

**So you can see that during loading Rank 1 doesn't take any more CPU RAM. And the performance between both setups matches.**

To Do:

- [ ] Add docs in the FSDP section

add util for ram efficient loading of model when using fsdp. # What does this PR do?
1. Fixes an issue explained in https://github.com/pytorch/pytorch/issues/105840 when using FSDP for training very large models. Should be merged after https://github.com/huggingface/accelerate/pull/1777

Currently, when using FSDP, the model is loaded for each of the N processes completely on CPU leading to huge CPU RAM usage. When training models like Flacon-40B with FSDP on a dgx node with 8 GPUs, it would lead to CPU RAM getting out of memory because each process is loading 160GB (40B x 4Bytes (FP32)) in CPU RAM for a total of 160*8=1280GB requirement which results in script getting killed due to out of CPU RAM.

To combat this, we load the model only on rank 0 and have it on meta device when rank!=0. Then use no-op param_init_fn along with sync_module_states=True for FSDP to properly init the weights on other ranks and broadcast the params from rank 0 to other ranks. 

Usage:

**No user-facing changes**:

Post this PR:
```
accelerator.process_index=0 GPU Memory before entering the loading : 0
accelerator.process_index=0 GPU Memory consumed at the end of the loading (end-begin): 0
accelerator.process_index=0 GPU Peak Memory consumed during the loading (max-begin): 0
accelerator.process_index=0 GPU Total Peak Memory consumed during the loading (max): 0
accelerator.process_index=0 CPU Memory before entering the loading : 926
accelerator.process_index=0 CPU Memory consumed at the end of the loading (end-begin): 26415
accelerator.process_index=0 CPU Peak Memory consumed during the loading (max-begin): 31818
accelerator.process_index=0 CPU Total Peak Memory consumed during the loading (max): 32744
accelerator.process_index=0 model.lm_head.weight=Parameter containing:
tensor([[-0.0179,  0.0201, -0.0273,  ..., -0.0275, -0.0396, -0.0131],
        [-0.0510, -0.0079, -0.0383,  ..., -0.0481,  0.0581,  0.0282],
        [-0.0217, -0.0216, -0.0064,  ..., -0.0508,  0.0554, -0.0013],
        ...,
        [ 0.0425,  0.0452, -0.0131,  ...,  0.0019,  0.0476,  0.0342],
        [-0.0170, -0.0085,  0.0449,  ..., -0.0074,  0.0178,  0.0043],
        [-0.0439, -0.0859, -0.0820,  ...,  0.0130,  0.0669,  0.0884]],
       requires_grad=True)
accelerator.process_index=1 GPU Memory before entering the loading : 0
accelerator.process_index=1 GPU Memory consumed at the end of the loading (end-begin): 0
accelerator.process_index=1 GPU Peak Memory consumed during the loading (max-begin): 0
accelerator.process_index=1 GPU Total Peak Memory consumed during the loading (max): 0
accelerator.process_index=1 CPU Memory before entering the loading : 933
accelerator.process_index=1 CPU Memory consumed at the end of the loading (end-begin): 10
accelerator.process_index=1 CPU Peak Memory consumed during the loading (max-begin): 573
accelerator.process_index=1 CPU Total Peak Memory consumed during the loading (max): 1506
accelerator.process_index=1 model.lm_head.weight=Parameter containing:
tensor([[0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.],
        ...,
        [0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.],
        [0., 0., 0.,  ..., 0., 0., 0.]], requires_grad=True)
accelerator.process_index=0 GPU Memory before entering the prepare : 0
accelerator.process_index=0 GPU Memory consumed at the end of the prepare (end-begin): 13202
accelerator.process_index=0 GPU Peak Memory consumed during the prepare (max-begin): 15458
accelerator.process_index=0 GPU Total Peak Memory consumed during the prepare (max): 15458
accelerator.process_index=0 CPU Memory before entering the prepare : 27345
accelerator.process_index=0 CPU Memory consumed at the end of the prepare (end-begin): -26394
accelerator.process_index=0 CPU Peak Memory consumed during the prepare (max-begin): 0
accelerator.process_index=0 CPU Total Peak Memory consumed during the prepare (max): 27345
FullyShardedDataParallel(
  (_fsdp_wrapped_module): RWForCausalLM(
    (transformer): RWModel(
      (word_embeddings): Embedding(65024, 4544)
      (h): ModuleList(
        (0-31): 32 x FullyShardedDataParallel(
          (_fsdp_wrapped_module): DecoderLayer(
            (input_layernorm): LayerNorm((4544,), eps=1e-05, elementwise_affine=True)
            (self_attention): Attention(
              (maybe_rotary): RotaryEmbedding()
              (query_key_value): Linear(in_features=4544, out_features=4672, bias=False)
              (dense): Linear(in_features=4544, out_features=4544, bias=False)
              (attention_dropout): Dropout(p=0.0, inplace=False)
            )
            (mlp): MLP(
              (dense_h_to_4h): Linear(in_features=4544, out_features=18176, bias=False)
              (act): GELU(approximate='none')
              (dense_4h_to_h): Linear(in_features=18176, out_features=4544, bias=False)
            )
          )
        )
      )
      (ln_f): LayerNorm((4544,), eps=1e-05, elementwise_affine=True)
    )
    (lm_head): Linear(in_features=4544, out_features=65024, bias=False)
  )
)
accelerator.process_index=1 GPU Memory before entering the prepare : 0
accelerator.process_index=1 GPU Memory consumed at the end of the prepare (end-begin): 13202
accelerator.process_index=1 GPU Peak Memory consumed during the prepare (max-begin): 15458
accelerator.process_index=1 GPU Total Peak Memory consumed during the prepare (max): 15458
accelerator.process_index=1 CPU Memory before entering the prepare : 945
accelerator.process_index=1 CPU Memory consumed at the end of the prepare (end-begin): 4
accelerator.process_index=1 CPU Peak Memory consumed during the prepare (max-begin): 4
accelerator.process_index=1 CPU Total Peak Memory consumed during the prepare (max): 949
accelerator.process_index=1 model.lm_head.weight=Parameter containing:
tensor([[-0.0179,  0.0201, -0.0273,  ..., -0.0275, -0.0396, -0.0131],
        [-0.0510, -0.0079, -0.0383,  ..., -0.0481,  0.0581,  0.0282],
        [-0.0217, -0.0216, -0.0064,  ..., -0.0508,  0.0554, -0.0013],
        ...,
        [ 0.0425,  0.0452, -0.0131,  ...,  0.0019,  0.0476,  0.0342],
        [-0.0170, -0.0085,  0.0449,  ..., -0.0074,  0.0178,  0.0043],
        [-0.0439, -0.0859, -0.0820,  ...,  0.0130,  0.0669,  0.0884]],
       device='cuda:1', requires_grad=True)
accelerator.process_index=0 model.lm_head.weight=Parameter containing:
tensor([[-0.0179,  0.0201, -0.0273,  ..., -0.0275, -0.0396, -0.0131],
        [-0.0510, -0.0079, -0.0383,  ..., -0.0481,  0.0581,  0.0282],
        [-0.0217, -0.0216, -0.0064,  ..., -0.0508,  0.0554, -0.0013],
        ...,
        [ 0.0425,  0.0452, -0.0131,  ...,  0.0019,  0.0476,  0.0342],
        [-0.0170, -0.0085,  0.0449,  ..., -0.0074,  0.0178,  0.0043],
        [-0.0439, -0.0859, -0.0820,  ...,  0.0130,  0.0669,  0.0884]],
       device='cuda:0', requires_grad=True)
```

**So you can see that during loading Rank 1 doesn't take any more CPU RAM. And the performance between both setups matches.**

To Do:

- [ ] Add docs in the FSDP section

# coding=utf-8
# Copyright 2021 HuggingFace Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import unittest

from datasets import load_dataset

from transformers.testing_utils import require_torch, require_vision
from transformers.utils import is_torch_available, is_vision_available

from ...test_image_processing_common import ImageProcessingTestMixin, prepare_image_inputs


if is_torch_available():
    import torch

if is_vision_available():
    from PIL import Image

    from transformers import SegformerImageProcessor


class SegformerImageProcessingTester(unittest.TestCase):
    def __init__(
        self,
        parent,
        batch_size=7,
        num_channels=3,
        min_resolution=30,
        max_resolution=400,
        do_resize=True,
        size=None,
        do_normalize=True,
        image_mean=[0.5, 0.5, 0.5],
        image_std=[0.5, 0.5, 0.5],
        do_reduce_labels=False,
    ):
        size = size if size is not None else {"height": 30, "width": 30}
        self.parent = parent
        self.batch_size = batch_size
        self.num_channels = num_channels
        self.min_resolution = min_resolution
        self.max_resolution = max_resolution
        self.do_resize = do_resize
        self.size = size
        self.do_normalize = do_normalize
        self.image_mean = image_mean
        self.image_std = image_std
        self.do_reduce_labels = do_reduce_labels

    def prepare_image_processor_dict(self):
        return {
            "do_resize": self.do_resize,
            "size": self.size,
            "do_normalize": self.do_normalize,
            "image_mean": self.image_mean,
            "image_std": self.image_std,
            "do_reduce_labels": self.do_reduce_labels,
        }

    def expected_output_image_shape(self, images):
        return self.num_channels, self.size["height"], self.size["width"]

    def prepare_image_inputs(self, equal_resolution=False, numpify=False, torchify=False):
        return prepare_image_inputs(
            batch_size=self.batch_size,
            num_channels=self.num_channels,
            min_resolution=self.min_resolution,
            max_resolution=self.max_resolution,
            equal_resolution=equal_resolution,
            numpify=numpify,
            torchify=torchify,
        )


def prepare_semantic_single_inputs():
    dataset = load_dataset("hf-internal-testing/fixtures_ade20k", split="test")

    image = Image.open(dataset[0]["file"])
    map = Image.open(dataset[1]["file"])

    return image, map


def prepare_semantic_batch_inputs():
    dataset = load_dataset("hf-internal-testing/fixtures_ade20k", split="test")

    image1 = Image.open(dataset[0]["file"])
    map1 = Image.open(dataset[1]["file"])
    image2 = Image.open(dataset[2]["file"])
    map2 = Image.open(dataset[3]["file"])

    return [image1, image2], [map1, map2]


@require_torch
@require_vision
class SegformerImageProcessingTest(ImageProcessingTestMixin, unittest.TestCase):
    image_processing_class = SegformerImageProcessor if is_vision_available() else None

    def setUp(self):
        self.image_processor_tester = SegformerImageProcessingTester(self)

    @property
    def image_processor_dict(self):
        return self.image_processor_tester.prepare_image_processor_dict()

    def test_image_processor_properties(self):
        image_processing = self.image_processing_class(**self.image_processor_dict)
        self.assertTrue(hasattr(image_processing, "do_resize"))
        self.assertTrue(hasattr(image_processing, "size"))
        self.assertTrue(hasattr(image_processing, "do_normalize"))
        self.assertTrue(hasattr(image_processing, "image_mean"))
        self.assertTrue(hasattr(image_processing, "image_std"))
        self.assertTrue(hasattr(image_processing, "do_reduce_labels"))

    def test_image_processor_from_dict_with_kwargs(self):
        image_processor = self.image_processing_class.from_dict(self.image_processor_dict)
        self.assertEqual(image_processor.size, {"height": 30, "width": 30})
        self.assertEqual(image_processor.do_reduce_labels, False)

        image_processor = self.image_processing_class.from_dict(self.image_processor_dict, size=42, reduce_labels=True)
        self.assertEqual(image_processor.size, {"height": 42, "width": 42})
        self.assertEqual(image_processor.do_reduce_labels, True)

    def test_call_segmentation_maps(self):
        # Initialize image_processing
        image_processing = self.image_processing_class(**self.image_processor_dict)
        # create random PyTorch tensors
        image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=False, torchify=True)
        maps = []
        for image in image_inputs:
            self.assertIsInstance(image, torch.Tensor)
            maps.append(torch.zeros(image.shape[-2:]).long())

        # Test not batched input
        encoding = image_processing(image_inputs[0], maps[0], return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                1,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                1,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

        # Test batched
        encoding = image_processing(image_inputs, maps, return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                self.image_processor_tester.batch_size,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                self.image_processor_tester.batch_size,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

        # Test not batched input (PIL images)
        image, segmentation_map = prepare_semantic_single_inputs()

        encoding = image_processing(image, segmentation_map, return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                1,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                1,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

        # Test batched input (PIL images)
        images, segmentation_maps = prepare_semantic_batch_inputs()

        encoding = image_processing(images, segmentation_maps, return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                2,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                2,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

    def test_reduce_labels(self):
        # Initialize image_processing
        image_processing = self.image_processing_class(**self.image_processor_dict)

        # ADE20k has 150 classes, and the background is included, so labels should be between 0 and 150
        image, map = prepare_semantic_single_inputs()
        encoding = image_processing(image, map, return_tensors="pt")
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 150)

        image_processing.do_reduce_labels = True
        encoding = image_processing(image, map, return_tensors="pt")
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

# coding=utf-8
# Copyright 2021 HuggingFace Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import unittest

from datasets import load_dataset

from transformers.testing_utils import require_torch, require_vision
from transformers.utils import is_torch_available, is_vision_available

from ...test_image_processing_common import ImageProcessingTestMixin, prepare_image_inputs


if is_torch_available():
    import torch

if is_vision_available():
    from PIL import Image

    from transformers import SegformerImageProcessor


class SegformerImageProcessingTester(unittest.TestCase):
    def __init__(
        self,
        parent,
        batch_size=7,
        num_channels=3,
        min_resolution=30,
        max_resolution=400,
        do_resize=True,
        size=None,
        do_normalize=True,
        image_mean=[0.5, 0.5, 0.5],
        image_std=[0.5, 0.5, 0.5],
        do_reduce_labels=False,
    ):
        size = size if size is not None else {"height": 30, "width": 30}
        self.parent = parent
        self.batch_size = batch_size
        self.num_channels = num_channels
        self.min_resolution = min_resolution
        self.max_resolution = max_resolution
        self.do_resize = do_resize
        self.size = size
        self.do_normalize = do_normalize
        self.image_mean = image_mean
        self.image_std = image_std
        self.do_reduce_labels = do_reduce_labels

    def prepare_image_processor_dict(self):
        return {
            "do_resize": self.do_resize,
            "size": self.size,
            "do_normalize": self.do_normalize,
            "image_mean": self.image_mean,
            "image_std": self.image_std,
            "do_reduce_labels": self.do_reduce_labels,
        }

    def expected_output_image_shape(self, images):
        return self.num_channels, self.size["height"], self.size["width"]

    def prepare_image_inputs(self, equal_resolution=False, numpify=False, torchify=False):
        return prepare_image_inputs(
            batch_size=self.batch_size,
            num_channels=self.num_channels,
            min_resolution=self.min_resolution,
            max_resolution=self.max_resolution,
            equal_resolution=equal_resolution,
            numpify=numpify,
            torchify=torchify,
        )


def prepare_semantic_single_inputs():
    dataset = load_dataset("hf-internal-testing/fixtures_ade20k", split="test")

    image = Image.open(dataset[0]["file"])
    map = Image.open(dataset[1]["file"])

    return image, map


def prepare_semantic_batch_inputs():
    dataset = load_dataset("hf-internal-testing/fixtures_ade20k", split="test")

    image1 = Image.open(dataset[0]["file"])
    map1 = Image.open(dataset[1]["file"])
    image2 = Image.open(dataset[2]["file"])
    map2 = Image.open(dataset[3]["file"])

    return [image1, image2], [map1, map2]


@require_torch
@require_vision
class SegformerImageProcessingTest(ImageProcessingTestMixin, unittest.TestCase):
    image_processing_class = SegformerImageProcessor if is_vision_available() else None

    def setUp(self):
        self.image_processor_tester = SegformerImageProcessingTester(self)

    @property
    def image_processor_dict(self):
        return self.image_processor_tester.prepare_image_processor_dict()

    def test_image_processor_properties(self):
        image_processing = self.image_processing_class(**self.image_processor_dict)
        self.assertTrue(hasattr(image_processing, "do_resize"))
        self.assertTrue(hasattr(image_processing, "size"))
        self.assertTrue(hasattr(image_processing, "do_normalize"))
        self.assertTrue(hasattr(image_processing, "image_mean"))
        self.assertTrue(hasattr(image_processing, "image_std"))
        self.assertTrue(hasattr(image_processing, "do_reduce_labels"))

    def test_image_processor_from_dict_with_kwargs(self):
        image_processor = self.image_processing_class.from_dict(self.image_processor_dict)
        self.assertEqual(image_processor.size, {"height": 30, "width": 30})
        self.assertEqual(image_processor.do_reduce_labels, False)

        image_processor = self.image_processing_class.from_dict(self.image_processor_dict, size=42, reduce_labels=True)
        self.assertEqual(image_processor.size, {"height": 42, "width": 42})
        self.assertEqual(image_processor.do_reduce_labels, True)

    def test_call_segmentation_maps(self):
        # Initialize image_processing
        image_processing = self.image_processing_class(**self.image_processor_dict)
        # create random PyTorch tensors
        image_inputs = self.image_processor_tester.prepare_image_inputs(equal_resolution=False, torchify=True)
        maps = []
        for image in image_inputs:
            self.assertIsInstance(image, torch.Tensor)
            maps.append(torch.zeros(image.shape[-2:]).long())

        # Test not batched input
        encoding = image_processing(image_inputs[0], maps[0], return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                1,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                1,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

        # Test batched
        encoding = image_processing(image_inputs, maps, return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                self.image_processor_tester.batch_size,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                self.image_processor_tester.batch_size,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

        # Test not batched input (PIL images)
        image, segmentation_map = prepare_semantic_single_inputs()

        encoding = image_processing(image, segmentation_map, return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                1,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                1,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

        # Test batched input (PIL images)
        images, segmentation_maps = prepare_semantic_batch_inputs()

        encoding = image_processing(images, segmentation_maps, return_tensors="pt")
        self.assertEqual(
            encoding["pixel_values"].shape,
            (
                2,
                self.image_processor_tester.num_channels,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(
            encoding["labels"].shape,
            (
                2,
                self.image_processor_tester.size["height"],
                self.image_processor_tester.size["width"],
            ),
        )
        self.assertEqual(encoding["labels"].dtype, torch.long)
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)

    def test_reduce_labels(self):
        # Initialize image_processing
        image_processing = self.image_processing_class(**self.image_processor_dict)

        # ADE20k has 150 classes, and the background is included, so labels should be between 0 and 150
        image, map = prepare_semantic_single_inputs()
        encoding = image_processing(image, map, return_tensors="pt")
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 150)

        image_processing.do_reduce_labels = True
        encoding = image_processing(image, map, return_tensors="pt")
        self.assertTrue(encoding["labels"].min().item() >= 0)
        self.assertTrue(encoding["labels"].max().item() <= 255)
