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 | 1 | +# Copyright 2024 The KerasNLP Authors  | 
 | 2 | +#  | 
 | 3 | +# Licensed under the Apache License, Version 2.0 (the "License");  | 
 | 4 | +# you may not use this file except in compliance with the License.  | 
 | 5 | +# You may obtain a copy of the License at  | 
 | 6 | +#  | 
 | 7 | +#     https://www.apache.org/licenses/LICENSE-2.0  | 
 | 8 | +#  | 
 | 9 | +# Unless required by applicable law or agreed to in writing, software  | 
 | 10 | +# distributed under the License is distributed on an "AS IS" BASIS,  | 
 | 11 | +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  | 
 | 12 | +# See the License for the specific language governing permissions and  | 
 | 13 | +# limitations under the License.  | 
 | 14 | +import numpy as np  | 
 | 15 | + | 
 | 16 | +from keras_nlp.src.utils.preset_utils import HF_CONFIG_FILE  | 
 | 17 | +from keras_nlp.src.utils.preset_utils import jax_memory_cleanup  | 
 | 18 | +from keras_nlp.src.utils.preset_utils import load_config  | 
 | 19 | +from keras_nlp.src.utils.timm.safetensor_utils import SafetensorLoader  | 
 | 20 | + | 
 | 21 | + | 
 | 22 | +def convert_backbone_config(timm_config):  | 
 | 23 | +    timm_architecture = timm_config["architecture"]  | 
 | 24 | + | 
 | 25 | +    if "resnetv2_" in timm_architecture:  | 
 | 26 | +        use_pre_activation = True  | 
 | 27 | +    else:  | 
 | 28 | +        use_pre_activation = False  | 
 | 29 | + | 
 | 30 | +    if timm_architecture == "resnet18":  | 
 | 31 | +        stackwise_num_blocks = [2, 2, 2, 2]  | 
 | 32 | +        block_type = "basic_block"  | 
 | 33 | +    elif timm_architecture == "resnet26":  | 
 | 34 | +        stackwise_num_blocks = [2, 2, 2, 2]  | 
 | 35 | +        block_type = "bottleneck_block"  | 
 | 36 | +    elif timm_architecture == "resnet34":  | 
 | 37 | +        stackwise_num_blocks = [3, 4, 6, 3]  | 
 | 38 | +        block_type = "basic_block"  | 
 | 39 | +    elif timm_architecture in ("resnet50", "resnetv2_50"):  | 
 | 40 | +        stackwise_num_blocks = [3, 4, 6, 3]  | 
 | 41 | +        block_type = "bottleneck_block"  | 
 | 42 | +    elif timm_architecture in ("resnet101", "resnetv2_101"):  | 
 | 43 | +        stackwise_num_blocks = [3, 4, 23, 3]  | 
 | 44 | +        block_type = "bottleneck_block"  | 
 | 45 | +    elif timm_architecture in ("resnet152", "resnetv2_152"):  | 
 | 46 | +        stackwise_num_blocks = [3, 8, 36, 3]  | 
 | 47 | +        block_type = "bottleneck_block"  | 
 | 48 | +    else:  | 
 | 49 | +        raise ValueError(  | 
 | 50 | +            f"Currently, the architecture {timm_architecture} is not supported."  | 
 | 51 | +        )  | 
 | 52 | + | 
 | 53 | +    return dict(  | 
 | 54 | +        stackwise_num_filters=[64, 128, 256, 512],  | 
 | 55 | +        stackwise_num_blocks=stackwise_num_blocks,  | 
 | 56 | +        stackwise_num_strides=[1, 2, 2, 2],  | 
 | 57 | +        block_type=block_type,  | 
 | 58 | +        use_pre_activation=use_pre_activation,  | 
 | 59 | +    )  | 
 | 60 | + | 
 | 61 | + | 
 | 62 | +def convert_weights(backbone, loader, timm_config):  | 
 | 63 | +    def transpose_conv2d(x, shape):  | 
 | 64 | +        return np.transpose(x, (2, 3, 1, 0))  | 
 | 65 | + | 
 | 66 | +    def port_conv2d(keras_layer_name, hf_weight_prefix):  | 
 | 67 | +        loader.port_weight(  | 
 | 68 | +            backbone.get_layer(keras_layer_name).kernel,  | 
 | 69 | +            hf_weight_key=f"{hf_weight_prefix}.weight",  | 
 | 70 | +            hook_fn=transpose_conv2d,  | 
 | 71 | +        )  | 
 | 72 | + | 
 | 73 | +    def port_batch_normalization(keras_layer_name, hf_weight_prefix):  | 
 | 74 | +        loader.port_weight(  | 
 | 75 | +            backbone.get_layer(keras_layer_name).gamma,  | 
 | 76 | +            hf_weight_key=f"{hf_weight_prefix}.weight",  | 
 | 77 | +        )  | 
 | 78 | +        loader.port_weight(  | 
 | 79 | +            backbone.get_layer(keras_layer_name).beta,  | 
 | 80 | +            hf_weight_key=f"{hf_weight_prefix}.bias",  | 
 | 81 | +        )  | 
 | 82 | +        loader.port_weight(  | 
 | 83 | +            backbone.get_layer(keras_layer_name).moving_mean,  | 
 | 84 | +            hf_weight_key=f"{hf_weight_prefix}.running_mean",  | 
 | 85 | +        )  | 
 | 86 | +        loader.port_weight(  | 
 | 87 | +            backbone.get_layer(keras_layer_name).moving_variance,  | 
 | 88 | +            hf_weight_key=f"{hf_weight_prefix}.running_var",  | 
 | 89 | +        )  | 
 | 90 | + | 
 | 91 | +    version = "v1" if not backbone.use_pre_activation else "v2"  | 
 | 92 | +    block_type = backbone.block_type  | 
 | 93 | + | 
 | 94 | +    # Stem  | 
 | 95 | +    if version == "v1":  | 
 | 96 | +        port_conv2d("conv1_conv", "conv1")  | 
 | 97 | +        port_batch_normalization("conv1_bn", "bn1")  | 
 | 98 | +    else:  | 
 | 99 | +        port_conv2d("conv1_conv", "stem.conv")  | 
 | 100 | + | 
 | 101 | +    # Stages  | 
 | 102 | +    num_stacks = len(backbone.stackwise_num_filters)  | 
 | 103 | +    for stack_index in range(num_stacks):  | 
 | 104 | +        for block_idx in range(backbone.stackwise_num_blocks[stack_index]):  | 
 | 105 | +            if version == "v1":  | 
 | 106 | +                keras_name = f"v1_stack{stack_index}_block{block_idx}"  | 
 | 107 | +                hf_name = f"layer{stack_index+1}.{block_idx}"  | 
 | 108 | +            else:  | 
 | 109 | +                keras_name = f"v2_stack{stack_index}_block{block_idx}"  | 
 | 110 | +                hf_name = f"stages.{stack_index}.blocks.{block_idx}"  | 
 | 111 | + | 
 | 112 | +            if version == "v1":  | 
 | 113 | +                if block_idx == 0 and (  | 
 | 114 | +                    block_type == "bottleneck_block" or stack_index > 0  | 
 | 115 | +                ):  | 
 | 116 | +                    port_conv2d(  | 
 | 117 | +                        f"{keras_name}_0_conv", f"{hf_name}.downsample.0"  | 
 | 118 | +                    )  | 
 | 119 | +                    port_batch_normalization(  | 
 | 120 | +                        f"{keras_name}_0_bn", f"{hf_name}.downsample.1"  | 
 | 121 | +                    )  | 
 | 122 | +                port_conv2d(f"{keras_name}_1_conv", f"{hf_name}.conv1")  | 
 | 123 | +                port_batch_normalization(f"{keras_name}_1_bn", f"{hf_name}.bn1")  | 
 | 124 | +                port_conv2d(f"{keras_name}_2_conv", f"{hf_name}.conv2")  | 
 | 125 | +                port_batch_normalization(f"{keras_name}_2_bn", f"{hf_name}.bn2")  | 
 | 126 | +                if block_type == "bottleneck_block":  | 
 | 127 | +                    port_conv2d(f"{keras_name}_3_conv", f"{hf_name}.conv3")  | 
 | 128 | +                    port_batch_normalization(  | 
 | 129 | +                        f"{keras_name}_3_bn", f"{hf_name}.bn3"  | 
 | 130 | +                    )  | 
 | 131 | +            else:  | 
 | 132 | +                if block_idx == 0 and (  | 
 | 133 | +                    block_type == "bottleneck_block" or stack_index > 0  | 
 | 134 | +                ):  | 
 | 135 | +                    port_conv2d(  | 
 | 136 | +                        f"{keras_name}_0_conv", f"{hf_name}.downsample.conv"  | 
 | 137 | +                    )  | 
 | 138 | +                port_batch_normalization(  | 
 | 139 | +                    f"{keras_name}_pre_activation_bn", f"{hf_name}.norm1"  | 
 | 140 | +                )  | 
 | 141 | +                port_conv2d(f"{keras_name}_1_conv", f"{hf_name}.conv1")  | 
 | 142 | +                port_batch_normalization(  | 
 | 143 | +                    f"{keras_name}_1_bn", f"{hf_name}.norm2"  | 
 | 144 | +                )  | 
 | 145 | +                port_conv2d(f"{keras_name}_2_conv", f"{hf_name}.conv2")  | 
 | 146 | +                if block_type == "bottleneck_block":  | 
 | 147 | +                    port_batch_normalization(  | 
 | 148 | +                        f"{keras_name}_2_bn", f"{hf_name}.norm3"  | 
 | 149 | +                    )  | 
 | 150 | +                    port_conv2d(f"{keras_name}_3_conv", f"{hf_name}.conv3")  | 
 | 151 | + | 
 | 152 | +    # Post  | 
 | 153 | +    if version == "v2":  | 
 | 154 | +        port_batch_normalization("post_bn", "norm")  | 
 | 155 | + | 
 | 156 | +    # Rebuild normalization layer with pretrained mean & std  | 
 | 157 | +    mean = timm_config["pretrained_cfg"]["mean"]  | 
 | 158 | +    std = timm_config["pretrained_cfg"]["std"]  | 
 | 159 | +    normalization_layer = backbone.get_layer("normalization")  | 
 | 160 | +    normalization_layer.input_mean = mean  | 
 | 161 | +    normalization_layer.input_variance = [s**2 for s in std]  | 
 | 162 | +    normalization_layer.build(normalization_layer._build_input_shape)  | 
 | 163 | + | 
 | 164 | + | 
 | 165 | +def load_resnet_backbone(cls, preset, load_weights, **kwargs):  | 
 | 166 | +    timm_config = load_config(preset, HF_CONFIG_FILE)  | 
 | 167 | +    keras_config = convert_backbone_config(timm_config)  | 
 | 168 | +    backbone = cls(**keras_config, **kwargs)  | 
 | 169 | +    if load_weights:  | 
 | 170 | +        jax_memory_cleanup(backbone)  | 
 | 171 | +        with SafetensorLoader(preset) as loader:  | 
 | 172 | +            convert_weights(backbone, loader, timm_config)  | 
 | 173 | +    return backbone  | 
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