# coding=utf-8
# Copyright 2021 NVIDIA and The HuggingFace Inc. team. All rights reserved.
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# you may not use this file except in compliance with the License.
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# http://www.apache.org/licenses/LICENSE-2.0
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""" SegFormer model configuration"""
import warnings
from collections import OrderedDict
from typing import Mapping
from packaging import version
from ...configuration_utils import PretrainedConfig
from ...onnx import OnnxConfig
from ...utils import logging
logger = logging.get_logger(__name__)
SEGFORMER_PRETRAINED_CONFIG_ARCHIVE_MAP = {
"nvidia/segformer-b0-finetuned-ade-512-512": (
"https://huggingface.co/nvidia/segformer-b0-finetuned-ade-512-512/resolve/main/config.json"
),
# See all SegFormer models at https://huggingface.co/models?filter=segformer
}
class SegformerConfig(PretrainedConfig):
r"""
This is the configuration class to store the configuration of a [`SegformerModel`]. It is used to instantiate an
SegFormer model according to the specified arguments, defining the model architecture. Instantiating a
configuration with the defaults will yield a similar configuration to that of the SegFormer
[nvidia/segformer-b0-finetuned-ade-512-512](https://huggingface.co/nvidia/segformer-b0-finetuned-ade-512-512)
architecture.
Configuration objects inherit from [`PretrainedConfig`] and can be used to control the model outputs. Read the
documentation from [`PretrainedConfig`] for more information.
Args:
num_channels (`int`, *optional*, defaults to 3):
The number of input channels.
num_encoder_blocks (`int`, *optional*, defaults to 4):
The number of encoder blocks (i.e. stages in the Mix Transformer encoder).
depths (`List[int]`, *optional*, defaults to [2, 2, 2, 2]):
The number of layers in each encoder block.
sr_ratios (`List[int]`, *optional*, defaults to [8, 4, 2, 1]):
Sequence reduction ratios in each encoder block.
hidden_sizes (`List[int]`, *optional*, defaults to [32, 64, 160, 256]):
Dimension of each of the encoder blocks.
patch_sizes (`List[int]`, *optional*, defaults to [7, 3, 3, 3]):
Patch size before each encoder block.
strides (`List[int]`, *optional*, defaults to [4, 2, 2, 2]):
Stride before each encoder block.
num_attention_heads (`List[int]`, *optional*, defaults to [1, 2, 5, 8]):
Number of attention heads for each attention layer in each block of the Transformer encoder.
mlp_ratios (`List[int]`, *optional*, defaults to [4, 4, 4, 4]):
Ratio of the size of the hidden layer compared to the size of the input layer of the Mix FFNs in the
encoder blocks.
hidden_act (`str` or `function`, *optional*, defaults to `"gelu"`):
The non-linear activation function (function or string) in the encoder and pooler. If string, `"gelu"`,
`"relu"`, `"selu"` and `"gelu_new"` are supported.
hidden_dropout_prob (`float`, *optional*, defaults to 0.0):
The dropout probability for all fully connected layers in the embeddings, encoder, and pooler.
attention_probs_dropout_prob (`float`, *optional*, defaults to 0.0):
The dropout ratio for the attention probabilities.
classifier_dropout_prob (`float`, *optional*, defaults to 0.1):
The dropout probability before the classification head.
initializer_range (`float`, *optional*, defaults to 0.02):
The standard deviation of the truncated_normal_initializer for initializing all weight matrices.
drop_path_rate (`float`, *optional*, defaults to 0.1):
The dropout probability for stochastic depth, used in the blocks of the Transformer encoder.
layer_norm_eps (`float`, *optional*, defaults to 1e-6):
The epsilon used by the layer normalization layers.
decoder_hidden_size (`int`, *optional*, defaults to 256):
The dimension of the all-MLP decode head.
semantic_loss_ignore_index (`int`, *optional*, defaults to 255):
The index that is ignored by the loss function of the semantic segmentation model.
Example:
```python
>>> from transformers import SegformerModel, SegformerConfig
>>> # Initializing a SegFormer nvidia/segformer-b0-finetuned-ade-512-512 style configuration
>>> configuration = SegformerConfig()
>>> # Initializing a model from the nvidia/segformer-b0-finetuned-ade-512-512 style configuration
>>> model = SegformerModel(configuration)
>>> # Accessing the model configuration
>>> configuration = model.config
```"""
model_type = "segformer"
def __init__(
self,
num_channels=3,
num_encoder_blocks=4,
depths=[2, 2, 2, 2],
sr_ratios=[8, 4, 2, 1],
hidden_sizes=[32, 64, 160, 256],
patch_sizes=[7, 3, 3, 3],
strides=[4, 2, 2, 2],
num_attention_heads=[1, 2, 5, 8],
mlp_ratios=[4, 4, 4, 4],
hidden_act="gelu",
hidden_dropout_prob=0.0,
attention_probs_dropout_prob=0.0,
classifier_dropout_prob=0.1,
initializer_range=0.02,
drop_path_rate=0.1,
layer_norm_eps=1e-6,
decoder_hidden_size=256,
semantic_loss_ignore_index=255,
**kwargs,
):
super().__init__(**kwargs)
if "reshape_last_stage" in kwargs and kwargs["reshape_last_stage"] is False:
warnings.warn(
"Reshape_last_stage is set to False in this config. This argument is deprecated and will soon be"
" removed, as the behaviour will default to that of reshape_last_stage = True.",
FutureWarning,
)
self.num_channels = num_channels
self.num_encoder_blocks = num_encoder_blocks
self.depths = depths
self.sr_ratios = sr_ratios
self.hidden_sizes = hidden_sizes
self.patch_sizes = patch_sizes
self.strides = strides
self.mlp_ratios = mlp_ratios
self.num_attention_heads = num_attention_heads
self.hidden_act = hidden_act
self.hidden_dropout_prob = hidden_dropout_prob
self.attention_probs_dropout_prob = attention_probs_dropout_prob
self.classifier_dropout_prob = classifier_dropout_prob
self.initializer_range = initializer_range
self.drop_path_rate = drop_path_rate
self.layer_norm_eps = layer_norm_eps
self.decoder_hidden_size = decoder_hidden_size
self.reshape_last_stage = kwargs.get("reshape_last_stage", True)
self.semantic_loss_ignore_index = semantic_loss_ignore_index
class SegformerOnnxConfig(OnnxConfig):
torch_onnx_minimum_version = version.parse("1.11")
@property
def inputs(self) -> Mapping[str, Mapping[int, str]]:
return OrderedDict(
[
("pixel_values", {0: "batch", 1: "num_channels", 2: "height", 3: "width"}),
]
)
@property
def atol_for_validation(self) -> float:
return 1e-4
@property
def default_onnx_opset(self) -> int:
return 12