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""" |
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Credit: ComfyUI |
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https://github.com/comfyanonymous/ComfyUI/blob/v0.3.7/comfy_extras/nodes_model_advanced.py#L257 |
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""" |
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import gradio as gr |
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import torch |
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from modules import scripts |
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from modules.infotext_utils import PasteField |
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from modules.shared import opts |
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class ScriptRescaleCFG(scripts.ScriptBuiltinUI): |
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section = "cfg" |
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create_group = False |
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def title(self): |
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return "RescaleCFG" |
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def show(self, is_img2img): |
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return scripts.AlwaysVisible if opts.show_rescale_cfg else None |
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def ui(self, is_img2img): |
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cfg = gr.Slider( |
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value=0.0, |
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minimum=0.0, |
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maximum=1.0, |
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step=0.05, |
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label="Rescale CFG", |
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elem_id=f"{'img2img' if is_img2img else 'txt2img'}_rescale_cfg_scale", |
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scale=4, |
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) |
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self.infotext_fields = [PasteField(cfg, "Rescale CFG", api="rescale_cfg")] |
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return [cfg] |
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def after_extra_networks_activate(self, p, cfg, *args, **kwargs): |
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if opts.show_rescale_cfg and cfg > 0.0: |
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p.extra_generation_params.update({"Rescale CFG": cfg}) |
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def process_before_every_sampling(self, p, cfg, *args, **kwargs): |
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if not opts.show_rescale_cfg or cfg < 0.05: |
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return |
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@torch.inference_mode() |
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def rescale_cfg(args): |
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cond = args["cond"] |
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uncond = args["uncond"] |
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cond_scale = args["cond_scale"] |
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sigma = args["sigma"] |
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sigma = sigma.view(sigma.shape[:1] + (1,) * (cond.ndim - 1)) |
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x_orig = args["input"] |
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x = x_orig / (sigma * sigma + 1.0) |
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cond = ((x - (x_orig - cond)) * (sigma**2 + 1.0) ** 0.5) / (sigma) |
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uncond = ((x - (x_orig - uncond)) * (sigma**2 + 1.0) ** 0.5) / (sigma) |
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x_cfg = uncond + cond_scale * (cond - uncond) |
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ro_pos = torch.std(cond, dim=(1, 2, 3), keepdim=True) |
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ro_cfg = torch.std(x_cfg, dim=(1, 2, 3), keepdim=True) |
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x_rescaled = x_cfg * (ro_pos / ro_cfg) |
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x_final = cfg * x_rescaled + (1.0 - cfg) * x_cfg |
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return x_orig - (x - x_final * sigma / (sigma * sigma + 1.0) ** 0.5) |
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unet = p.sd_model.forge_objects.unet.clone() |
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unet.set_model_sampler_cfg_function(rescale_cfg) |
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p.sd_model.forge_objects.unet = unet |
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print(f"rescale_cfg = {cfg}") |
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