# # SPDX-FileCopyrightText: Copyright (c) 1993-2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved. # SPDX-License-Identifier: Apache-2.0 # # 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 os import re from collections import defaultdict from random import choice, shuffle from typing import Set import modelopt.torch.quantization as mtq import numpy as np import onnx_graphsurgeon as gs import torch import torch.nn.functional as F from diffusers.models.attention_processor import ( Attention, AttnProcessor, FluxAttnProcessor2_0, ) from diffusers.models.lora import LoRACompatibleConv, LoRACompatibleLinear from modelopt.torch.quantization import utils as quant_utils from modelopt.torch.quantization.calib.max import MaxCalibrator from PIL import Image from torch.utils.data import Dataset, Sampler import onnx USE_PEFT = True try: from peft.tuners.lora.layer import Conv2d as PEFTLoRAConv2d from peft.tuners.lora.layer import Linear as PEFTLoRALinear except ModuleNotFoundError: USE_PEFT = False class PercentileCalibrator(MaxCalibrator): def __init__(self, num_bits=8, axis=None, unsigned=False, track_amax=False, **kwargs): super().__init__(num_bits, axis, unsigned, track_amax) self.percentile = kwargs["percentile"] self.total_step = kwargs["total_step"] self.collect_method = kwargs["collect_method"] self.data = {} self.i = 0 def collect(self, x): """Tracks the absolute max of all tensors. Args: x: A tensor Raises: RuntimeError: If amax shape changes """ # Swap axis to reduce. axis = self._axis if isinstance(self._axis, (list, tuple)) else [self._axis] # Handle negative axis. axis = [x.dim() + i if isinstance(i, int) and i < 0 else i for i in axis] reduce_axis = [] for i in range(x.dim()): if i not in axis: reduce_axis.append(i) local_amax = quant_utils.reduce_amax(x, axis=reduce_axis).detach() _cur_step = self.i % self.total_step if _cur_step not in self.data.keys(): self.data[_cur_step] = local_amax else: if self.collect_method == "global_min": self.data[_cur_step] = torch.min(self.data[_cur_step], local_amax) elif self.collect_method == "min-max" or self.collect_method == "mean-max": self.data[_cur_step] = torch.max(self.data[_cur_step], local_amax) else: self.data[_cur_step] += local_amax if self._track_amax: raise NotImplementedError self.i += 1 def compute_amax(self): """Return the absolute max of all tensors collected.""" up_lim = int(self.total_step * self.percentile) if self.collect_method == "min-mean": amaxs_values = [self.data[i] / self.total_step for i in range(0, up_lim)] else: amaxs_values = [self.data[i] for i in range(0, up_lim)] if self.collect_method == "mean-max": act_amax = torch.vstack(amaxs_values).mean(axis=0)[0] else: act_amax = torch.vstack(amaxs_values).min(axis=0)[0] self._calib_amax = act_amax return self._calib_amax def __str__(self): s = "PercentileCalibrator" return s.format(**self.__dict__) def __repr__(self): s = "PercentileCalibrator(" s += super(MaxCalibrator, self).__repr__() s += " calib_amax={_calib_amax}" if self._track_amax: s += " amaxs={_amaxs}" s += ")" return s.format(**self.__dict__) def filter_func(name): pattern = re.compile( r".*(time_emb_proj|time_embedding|conv_in|conv_out|conv_shortcut|add_embedding|pos_embed|time_text_embed|context_embedder|norm_out|proj_out).*" ) return pattern.match(name) is not None def filter_func_no_proj_out(name): # used for Flux pattern = re.compile( r".*(time_emb_proj|time_embedding|conv_in|conv_out|conv_shortcut|add_embedding|pos_embed|time_text_embed|context_embedder|norm_out|x_embedder).*" ) return pattern.match(name) is not None def quantize_lvl(model_id, backbone, quant_level=2.5, linear_only=False, enable_conv_3d=True): """ We should disable the unwanted quantizer when exporting the onnx Because in the current modelopt setting, it will load the quantizer amax for all the layers even if we didn't add that unwanted layer into the config during the calibration """ for name, module in backbone.named_modules(): if isinstance(module, torch.nn.Conv2d): if linear_only: module.input_quantizer.disable() module.weight_quantizer.disable() else: module.input_quantizer.enable() module.weight_quantizer.enable() elif isinstance(module, torch.nn.Linear): if ( (quant_level >= 2 and "ff.net" in name) or (quant_level >= 2.5 and ("to_q" in name or "to_k" in name or "to_v" in name)) or quant_level >= 3 ) and name != "proj_out": # Disable the final output layer from flux model module.input_quantizer.enable() module.weight_quantizer.enable() else: module.input_quantizer.disable() module.weight_quantizer.disable() elif isinstance(module, torch.nn.Conv3d) and not enable_conv_3d: """ Error: Torch bug, ONNX export failed due to unknown kernel shape in QuantConv3d. TRT_FP8QuantizeLinear and TRT_FP8DequantizeLinear operations in UNetSpatioTemporalConditionModel for svd cause issues. Inputs on different devices (CUDA vs CPU) may contribute to the problem. """ module.input_quantizer.disable() module.weight_quantizer.disable() elif isinstance(module, Attention): # TRT only supports FP8 MHA with head_size % 16 == 0. head_size = int(module.inner_dim / module.heads) if quant_level >= 4 and head_size % 16 == 0: module.q_bmm_quantizer.enable() module.k_bmm_quantizer.enable() module.v_bmm_quantizer.enable() module.softmax_quantizer.enable() if model_id.startswith("flux.1"): if name.startswith("transformer_blocks"): module.bmm2_output_quantizer.enable() else: module.bmm2_output_quantizer.disable() setattr(module, "_disable_fp8_mha", False) else: module.q_bmm_quantizer.disable() module.k_bmm_quantizer.disable() module.v_bmm_quantizer.disable() module.softmax_quantizer.disable() module.bmm2_output_quantizer.disable() setattr(module, "_disable_fp8_mha", True) def fp8_mha_disable(backbone, quantized_mha_output: bool = True): def mha_filter_func(name): pattern = re.compile( r".*(q_bmm_quantizer|k_bmm_quantizer|v_bmm_quantizer|softmax_quantizer).*" if quantized_mha_output else r".*(q_bmm_quantizer|k_bmm_quantizer|v_bmm_quantizer|softmax_quantizer|bmm2_output_quantizer).*" ) return pattern.match(name) is not None if hasattr(F, "scaled_dot_product_attention"): mtq.disable_quantizer(backbone, mha_filter_func) def get_int8_config( model, quant_level=3, alpha=0.8, percentile=1.0, num_inference_steps=20, collect_method="min-mean", ): quant_config = { "quant_cfg": { "*lm_head*": {"enable": False}, "*output_layer*": {"enable": False}, "*output_quantizer": {"enable": False}, "default": {"num_bits": 8, "axis": None}, }, "algorithm": {"method": "smoothquant", "alpha": alpha}, } for name, module in model.named_modules(): w_name = f"{name}*weight_quantizer" i_name = f"{name}*input_quantizer" if w_name in quant_config["quant_cfg"].keys() or i_name in quant_config["quant_cfg"].keys(): continue if filter_func(name): continue if isinstance(module, (torch.nn.Linear, LoRACompatibleLinear)): if ( (quant_level >= 2 and "ff.net" in name) or (quant_level >= 2.5 and ("to_q" in name or "to_k" in name or "to_v" in name)) or quant_level == 3 ): quant_config["quant_cfg"][w_name] = {"num_bits": 8, "axis": 0} quant_config["quant_cfg"][i_name] = {"num_bits": 8, "axis": -1} elif isinstance(module, (torch.nn.Conv2d, LoRACompatibleConv)): quant_config["quant_cfg"][w_name] = {"num_bits": 8, "axis": 0} quant_config["quant_cfg"][i_name] = { "num_bits": 8, "axis": None, "calibrator": ( PercentileCalibrator, (), { "num_bits": 8, "axis": None, "percentile": percentile, "total_step": num_inference_steps, "collect_method": collect_method, }, ), } return quant_config SD_FP8_FP16_DEFAULT_CONFIG = { "quant_cfg": { "*weight_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Half"}, "*input_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Half"}, "*output_quantizer": {"enable": False}, "*q_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Half"}, "*k_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Half"}, "*v_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Half"}, "*softmax_quantizer": { "num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Half", }, "default": {"enable": False}, }, "algorithm": "max", } SD_FP8_BF16_DEFAULT_CONFIG = { "quant_cfg": { "*weight_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*input_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*output_quantizer": {"enable": False}, "*q_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*k_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*v_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*softmax_quantizer": { "num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16", }, "default": {"enable": False}, }, "algorithm": "max", } SD_FP8_BF16_FLUX_MMDIT_BMM2_FP8_OUTPUT_CONFIG = { "quant_cfg": { "*weight_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*input_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*output_quantizer": {"enable": False}, "*q_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*k_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*v_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16"}, "*softmax_quantizer": { "num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16", }, "transformer_blocks*bmm2_output_quantizer": { "num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "BFloat16", }, "default": {"enable": False}, }, "algorithm": "max", } SD_FP8_FP32_DEFAULT_CONFIG = { "quant_cfg": { "*weight_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Float"}, "*input_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Float"}, "*output_quantizer": {"enable": False}, "*q_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Float"}, "*k_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Float"}, "*v_bmm_quantizer": {"num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Float"}, "*softmax_quantizer": { "num_bits": (4, 3), "axis": None, "trt_high_precision_dtype": "Float", }, "default": {"enable": False}, }, "algorithm": "max", } def set_fmha(denoiser, is_flux=False): for name, module in denoiser.named_modules(): if isinstance(module, Attention): if is_flux: module.set_processor(FluxAttnProcessor2_0()) else: module.set_processor(AttnProcessor()) def check_lora(model): for name, module in model.named_modules(): if isinstance(module, (LoRACompatibleConv, LoRACompatibleLinear)): assert ( module.lora_layer is None ), f"To quantize {name}, LoRA layer should be fused/merged. Please fuse the LoRA layer before quantization." elif USE_PEFT and isinstance(module, (PEFTLoRAConv2d, PEFTLoRALinear)): assert ( module.merged ), f"To quantize {name}, LoRA layer should be fused/merged. Please fuse the LoRA layer before quantization." def generate_fp8_scales(unet): # temporary solution due to a known bug in torch.onnx._dynamo_export for _, module in unet.named_modules(): if isinstance(module, (torch.nn.Linear, torch.nn.Conv2d)) and ( hasattr(module.input_quantizer, "_amax") and module.input_quantizer is not None ): module.input_quantizer._num_bits = 8 module.weight_quantizer._num_bits = 8 module.input_quantizer._amax = module.input_quantizer._amax * (127 / 448.0) module.weight_quantizer._amax = module.weight_quantizer._amax * (127 / 448.0) elif isinstance(module, Attention) and ( hasattr(module.q_bmm_quantizer, "_amax") and module.q_bmm_quantizer is not None and hasattr(module.k_bmm_quantizer, "_amax") and module.k_bmm_quantizer is not None and hasattr(module.v_bmm_quantizer, "_amax") and module.v_bmm_quantizer is not None and hasattr(module.softmax_quantizer, "_amax") and module.softmax_quantizer is not None ): module.q_bmm_quantizer._num_bits = 8 module.q_bmm_quantizer._amax = module.q_bmm_quantizer._amax * (127 / 448.0) module.k_bmm_quantizer._num_bits = 8 module.k_bmm_quantizer._amax = module.k_bmm_quantizer._amax * (127 / 448.0) module.v_bmm_quantizer._num_bits = 8 module.v_bmm_quantizer._amax = module.v_bmm_quantizer._amax * (127 / 448.0) module.softmax_quantizer._num_bits = 8 module.softmax_quantizer._amax = module.softmax_quantizer._amax * (127 / 448.0) def get_parent_nodes(node): """ Returns list of input producer nodes for the given node. """ parents = [] for tensor in node.inputs: # If the tensor is not a constant or graph input and has a producer, # the producer is a parent of node `node` if len(tensor.inputs) == 1: parents.append(tensor.inputs[0]) return parents def get_child_nodes(node): """ Returns list of output consumer nodes for the given node. """ children = [] for tensor in node.outputs: for consumer in tensor.outputs: # Traverse all consumer of the tensor children.append(consumer) return children def has_path_type(node, graph, path_type, is_forward, wild_card_types, path_nodes): """ Return pattern nodes for the given path_type. """ if not path_type: # All types matched return True # Check if current non-wild node type does not match the expected path type node_type = node.op is_match = node_type == path_type[0] is_wild_match = node_type in wild_card_types if not is_match and not is_wild_match: return False if is_match: path_nodes.append(node) next_path_type = path_type[1:] else: next_path_type = path_type[:] if is_forward: next_level_nodes = get_child_nodes(node) else: next_level_nodes = get_parent_nodes(node) # Check if any child (forward path) or parent (backward path) can match the remaining path types for next_node in next_level_nodes: sub_path = [] if has_path_type(next_node, graph, next_path_type, is_forward, wild_card_types, sub_path): path_nodes.extend(sub_path) return True # Path type matches if there is no remaining types to match return not next_path_type def insert_cast(graph, input_tensor, attrs): """ Create a cast layer using tensor as input. """ output_tensor = gs.Variable(name=f"{input_tensor.name}/Cast_output", dtype=attrs["to"]) next_node_list = input_tensor.outputs.copy() graph.layer( op="Cast", name=f"{input_tensor.name}/Cast", inputs=[input_tensor], outputs=[output_tensor], attrs=attrs, ) # use cast output as input to next node for next_node in next_node_list: for idx, next_input in enumerate(next_node.inputs): if next_input.name == input_tensor.name: next_node.inputs[idx] = output_tensor def cast_layernorm_io(graph): """ Cast LayerNormalization scale and bias inputs from FP16 to FP32. In INT8 quantized graphs, DequantizeLinear outputs Float32 activations, but LayerNorm scale/bias remain FP16 from the original model, causing a type mismatch with --strongly-typed TensorRT builds. """ layernorm_nodes = [node for node in graph.nodes if node.op == "LayerNormalization"] print(f"Found {len(layernorm_nodes)} LayerNormalization nodes to fix") for node in layernorm_nodes: # LayerNormalization inputs: 0=X (data), 1=Scale, 2=B (bias, optional) for i in range(1, len(node.inputs)): input_tensor = node.inputs[i] if input_tensor.name and hasattr(input_tensor, 'dtype') and input_tensor.dtype == np.float16: insert_cast(graph, input_tensor=input_tensor, attrs={"to": np.float32}) def cast_convtranspose_io(graph): """ Fix ConvTranspose input/output type mismatches for strongly-typed TRT builds. In mixed-precision graphs (e.g. BF16 Stable Cascade VQGAN), architectural FP16->FP32 casts can leave a ConvTranspose with a FP32 activation input but FP16 kernel weights. We cast the activation to match the kernel dtype, then cast the output back to the original activation dtype so surrounding FP32 ops (e.g. residual Add) are unaffected. """ convtranspose_nodes = [node for node in graph.nodes if node.op == "ConvTranspose"] fixed = 0 for node in convtranspose_nodes: if len(node.inputs) < 2: continue act_input = node.inputs[0] kernel = node.inputs[1] if act_input.dtype is None or kernel.dtype is None or act_input.dtype == kernel.dtype: continue orig_dtype = act_input.dtype # e.g. np.dtype('float32') target_dtype = kernel.dtype.type # e.g. np.float16 insert_cast(graph, input_tensor=act_input, attrs={"to": target_dtype}) # Update the output dtype to match and cast back, so downstream FP32 ops are unaffected. for out in node.outputs: if out.name and out.dtype == orig_dtype: out.dtype = target_dtype insert_cast(graph, input_tensor=out, attrs={"to": orig_dtype.type}) fixed += 1 print(f"Fixed {fixed} ConvTranspose input/output type mismatches") def convert_zp_fp8(onnx_graph): """ Convert Q/DQ zero datatype from INT8 to FP8. """ # Find all zero constant nodes qdq_zero_nodes = set() for node in onnx_graph.graph.node: if node.op_type == "QuantizeLinear": if len(node.input) > 2: qdq_zero_nodes.add(node.input[2]) print(f"Found {len(qdq_zero_nodes)} QDQ pairs") # Convert zero point datatype from INT8 to FP8. for node in onnx_graph.graph.node: if node.output[0] in qdq_zero_nodes: node.attribute[0].t.data_type = onnx.TensorProto.FLOAT8E4M3FN return onnx_graph def cast_resize_io(graph, output_dtype=np.float16): """ Add cast nodes to Resize nodes I/O because Resize needs to be run in fp32. Inputs are cast to FP32, outputs are cast back to output_dtype (FP16 or BF16). """ resize_nodes = [node for node in graph.nodes if node.op == "Resize"] print(f"Found {len(resize_nodes)} Resize nodes to fix") for resize_node in resize_nodes: # Skip Resize nodes whose data input is already FP32 — no casting needed. if resize_node.inputs[0].dtype == np.float32: continue for i, input_tensor in enumerate(resize_node.inputs): SIZES_INPUT_INDEX = 3 # Optional input "sizes" at index 3 must be in INT64. Skip cast for this input. if i != SIZES_INPUT_INDEX and input_tensor.name: insert_cast(graph, input_tensor=input_tensor, attrs={"to": np.float32}) for output_tensor in resize_node.outputs: if output_tensor.name: insert_cast(graph, input_tensor=output_tensor, attrs={"to": output_dtype}) def cast_fp8_mha_io(graph): r""" Insert three cast ops. The first cast will be added before the input0 of MatMul to cast fp16 to fp32. The second cast will be added before the input1 of MatMul to cast fp16 to fp32. The third cast will be added after the output of MatMul to cast fp32 back to fp16. Q Q | | DQ DQ | | Cast Cast (fp16 to fp32) (fp16 to fp32) \ / \ / \ / MatMul | Cast (fp32 to fp16) | Q | DQ The insertion of Cast ops in the FP8 MHA part actually forbids the MHAs to run with FP16 accumulation because TensorRT only has FP32 accumulation kernels for FP8 MHAs. """ # Find FP8 MHA pattern. # Match FP8 MHA: Q -> DQ -> BMM1 -> (Mul/Div) -> (Add) -> Softmax -> (Cast) -> Q -> DQ -> BMM2 -> Q -> DQ softmax_bmm1_chain_type = ["Softmax", "MatMul", "DequantizeLinear", "QuantizeLinear"] softmax_bmm2_chain_type = [ "Softmax", "QuantizeLinear", "DequantizeLinear", "MatMul", "QuantizeLinear", "DequantizeLinear", ] wild_card_types = [ "Div", "Mul", "ConstMul", "Add", "BiasAdd", "Reshape", "Transpose", "Flatten", "Cast", ] fp8_mha_partitions = [] for node in graph.nodes: if node.op == "Softmax": fp8_mha_partition = [] if has_path_type( node, graph, softmax_bmm1_chain_type, False, wild_card_types, fp8_mha_partition ) and has_path_type( node, graph, softmax_bmm2_chain_type, True, wild_card_types, fp8_mha_partition ): if ( len(fp8_mha_partition) == 10 and fp8_mha_partition[1].op == "MatMul" and fp8_mha_partition[7].op == "MatMul" ): fp8_mha_partitions.append(fp8_mha_partition) print(f"Found {len(fp8_mha_partitions)} FP8 attentions") # Insert Cast nodes for BMM1 and BMM2. for fp8_mha_partition in fp8_mha_partitions: bmm1_node = fp8_mha_partition[1] insert_cast(graph, input_tensor=bmm1_node.inputs[0], attrs={"to": np.float32}) insert_cast(graph, input_tensor=bmm1_node.inputs[1], attrs={"to": np.float32}) insert_cast(graph, input_tensor=bmm1_node.outputs[0], attrs={"to": np.float16}) bmm2_node = fp8_mha_partition[7] insert_cast(graph, input_tensor=bmm2_node.inputs[0], attrs={"to": np.float32}) insert_cast(graph, input_tensor=bmm2_node.inputs[1], attrs={"to": np.float32}) insert_cast(graph, input_tensor=bmm2_node.outputs[0], attrs={"to": np.float16}) def set_quant_precision(quant_config, precision: str = "Half"): for key in quant_config["quant_cfg"]: if "trt_high_precision_dtype" in quant_config["quant_cfg"][key]: quant_config["quant_cfg"][key]["trt_high_precision_dtype"] = precision def convert_fp16_io(graph): """ Convert graph I/O to FP16. """ for input_tensor in graph.inputs: input_tensor.dtype = onnx.TensorProto.FLOAT16 for output_tensor in graph.outputs: output_tensor.dtype = onnx.TensorProto.FLOAT16 def random_resize(cur_size: int): """ Randomly selects a new resolution for an image based on its current aspect ratio. This function determines the current aspect ratio of an image, selects a new aspect ratio from predefined choices depending on whether the current aspect ratio is square, portrait, or landscape, and returns the corresponding resolution from a provided mapping. Parameters: cur_size (int): A tuple (width, height) representing the current resolution of the image. resolution_to_aspects (dict[float, tuple[int, int]]): A mapping of aspect ratios (floats) to their corresponding resolutions as tuples of (width, height). Returns: tuple[int, int]: A tuple (new_width, new_height) representing the newly selected resolution. Raises: KeyError: If the chosen aspect ratio is not present in the `resolution_to_aspects` dictionary. Notes: - For square images (aspect ratio = 1), the function selects from aspect ratios 1.25, 0.8, 1.5, and 0.667. - For landscape images (aspect ratio > 1), the function selects from aspect ratios 1.778, 1.25, and 1.5. - For portrait images (aspect ratio < 1), the function selects from aspect ratios 0.563, 0.8, and 0.667. """ resolution_to_aspects = { 1.0: (1024, 1024), 1.778: (768, 1344), 0.563: (1344, 768), 1.25: (896, 1152), 0.8: (1152, 896), 1.5: (832, 1216), 0.667: (1216, 832), } cur_aspect_ratio = round(cur_size[1] / cur_size[0], 3) if cur_aspect_ratio == 1: new_aspect_ratio = choice((1.25, 0.8, 1.5, 0.667)) new_res = resolution_to_aspects[new_aspect_ratio] elif cur_aspect_ratio > 1: new_aspect_ratio = choice((1.778, 1.25, 1.5)) new_res = resolution_to_aspects[new_aspect_ratio] else: # cur_aspect_ratio < 1 new_aspect_ratio = choice((0.563, 0.8, 0.667)) new_res = resolution_to_aspects[new_aspect_ratio] return new_res class PromptImageDataset(Dataset): def __init__( self, root_dir, ): """ Args: root_dir (str): Directory with all the images and the prompt file. """ self.root_dir = root_dir self.possible_resolutions = {1024, 768, 1344, 896, 832, 1216} self.global_idx_template = "{} | {} | {}" self.prompts_by_size = defaultdict(list) self.images_by_size = defaultdict(list) self.images = [] self.prompts = [] self.images_size = [] # self.global_idx_2_group = dict() # self.global_idx_to_group_idx = dict() self.group_to_global_idx = {} for idx, file in enumerate(os.listdir(os.path.join(self.root_dir, "prompts"))): if not file.endswith(".txt"): continue file_name = os.path.splitext(file)[0] image_path = os.path.join( self.root_dir, "inputs", f"{file_name}.png", ) with Image.open(image_path) as img, open(os.path.join(self.root_dir, "prompts", file), "r") as f: prompt = "\n".join(f.readlines()) std_img_size = ( self.closest_value(img.size[0], self.possible_resolutions), self.closest_value(img.size[1], self.possible_resolutions), ) self.images_by_size[std_img_size].append(image_path) self.prompts_by_size[std_img_size].append(prompt) self.images.append(image_path) self.prompts.append(prompt) self.images_size.append(std_img_size) # create a unique key that map group and index inside the group to a global index in_group_idx = len(self.images_by_size[std_img_size]) - 1 group_idx_key = self.global_idx_template.format(std_img_size[0], std_img_size[1], in_group_idx) self.group_to_global_idx[group_idx_key] = len(self.images) - 1 assert len(self.images) == len(self.prompts) assert len(self.images) == len(self.group_to_global_idx) @staticmethod def closest_value(target: int, candidates: Set[int]): """ Find the closest value to the target from a set of candidate values. Args: target (int): The integer to compare against. candidates (set): A set of integers as candidates. Returns: int: The closest value from the candidates. """ if not candidates: raise ValueError("The candidates set cannot be empty.") # Use the min function with a key that computes the absolute difference return min(candidates, key=lambda x: abs(x - target)) def __len__(self): return len(self.images) def __getitem__(self, idx): """ Returns: image (Tensor): Transformed image. prompt (str): Corresponding text prompt. """ if torch.is_tensor(idx): idx = idx.tolist() prompt = self.prompts[idx] image = self.images[idx] image_size = self.images_size[idx] return image, prompt, image_size class SameSizeSampler(Sampler): def __init__(self, dataset: PromptImageDataset, batch_size: int): """ Custom sampler that creates batches of images with the same size Args: dataset (SameSizeImageDataset): Dataset to sample from batch_size (int): Number of images per batch """ super().__init__(dataset) self.dataset = dataset self.batch_size = batch_size # Prepare size groups with indices self.size_groups = {} for size, image_paths in self.dataset.images_by_size.items(): # Create a list of indices for this size group self.size_groups[size] = list(range(len(image_paths))) def __iter__(self): """ Iteration method that yields indices for batches of same-size images """ # Create a copy of size groups to shuffle size_groups_copy = {std_img_size: indices.copy() for std_img_size, indices in self.size_groups.items()} # Shuffle each size group for std_img_size, indices in size_groups_copy.items(): shuffle(indices) # Iterate through size groups for std_img_size, indices in size_groups_copy.items(): # Batch indices of the same size for i in range(0, len(indices), self.batch_size): # Yield batch indices for this size batch_group_idxs = indices[i : min(i + self.batch_size, len(indices))] for in_group_idx in batch_group_idxs: group_idx_key = self.dataset.global_idx_template.format( std_img_size[0], std_img_size[1], in_group_idx ) batch_global_idx = self.dataset.group_to_global_idx[group_idx_key] # batch_global_idxs.append(batch_global_idx) yield batch_global_idx def __len__(self): """ Total number of batches """ return len(self.dataset.images) // self.batch_size def custom_collate(data): """ Custom collate function to handle batches of same-size images Args: dataset (SameSizeImageDataset): Dataset instance batch (list): List of global indices Returns: tuple: Batched images and their size """ # Group images by their size images, prompts, image_sizes = tuple(map(list, zip(*data))) assert len(images) > 0 new_img_size = random_resize(image_sizes[0]) batch_images = [] for image in images: with Image.open(image) as image: image = image.convert("RGB").resize(size=new_img_size, resample=Image.LANCZOS) image = np.array(image) image = np.transpose(image, axes=(-1, 0, 1)) image = torch.from_numpy(image).float() / 127.5 - 1.0 batch_images.append(image) batch_images = torch.stack(batch_images, dim=0) return batch_images, prompts def infinite_dataloader(dataloader): while True: for batch in dataloader: yield batch