app.py

# AUTOGENERATED! DO NOT EDIT! File to edit: app.ipynb.

# %% auto 0
__all__ = ['model_name', 'device', 'better_vae', 'unet_attn_slice', 'sampler_kls', 'hf_sampler', 'model_kwargs', 'num_steps',
           'height', 'width', 'k_sampler', 'use_karras_sigmas', 'NEG_PROMPT', 'generation_kwargs', 'baseline_g',
           'max_val', 'min_val', 'num_warmup_steps', 'warmup_init_val', 'num_cycles', 'k_decay', 'DEFAULT_COS_PARAMS',
           'static_sched', 'k_sched', 'inv_k_sched', 'scheds', 'iface', 'load_model', 'cos_harness',
           'compare_dynamic_guidance']

# %% app.ipynb 1
import gradio as gr
from cf_guidance import schedules, transforms
from min_diffusion.core import MinimalDiffusion
import torch
import nbdev

# %% app.ipynb 2
## MODEL SETUP
######################################
######################################
model_name = 'stabilityai/stable-diffusion-2'
device = ('cpu','cuda')[torch.cuda.is_available()]
if device == 'cuda':
    revision = 'fp16'
    dtype = torch.float16
else:
    revision = 'fp32'
    dtype = torch.float32

# model parameters
better_vae = ''
unet_attn_slice = True
sampler_kls = 'dpm_multi'
hf_sampler = 'dpm_multi'

model_kwargs = {
    'better_vae': better_vae,
    'unet_attn_slice': unet_attn_slice,
    'scheduler_kls': hf_sampler,
}

def load_model():
    pipeline = MinimalDiffusion(
        model_name,
        device,
        dtype,
        revision,
        **model_kwargs,
    )
    pipeline.load()
    return pipeline
######################################
######################################

# %% app.ipynb 3
## GENERATION PARAMETERS
######################################
######################################
num_steps = 18
height, width = 768, 768
k_sampler = 'k_dpmpp_2m' #'k_dpmpp_sde'
use_karras_sigmas = True

# a good negative prompt
NEG_PROMPT = "ugly, stock photo, tiling, poorly drawn hands, poorly drawn feet, poorly drawn face, out of frame, mutation, mutated, extra limbs, extra legs, extra arms, disfigured, deformed, cross-eye, body out of frame, blurry, bad art, bad anatomy, blurred, text, watermark, grainy"

generation_kwargs = {
    'num_steps': num_steps,
    'height': height,
    'width': width,
    'k_sampler':  k_sampler,
    'negative_prompt': NEG_PROMPT,
    'use_karras_sigmas': use_karras_sigmas,
}
######################################
######################################

# %% app.ipynb 4
## dynamicCFG SETUP
######################################
######################################

# default cosine schedule parameters
baseline_g        = 9    # default, static guidance value
max_val           = 9    # the max scheduled guidance scaling value
min_val           = 6    # the minimum scheduled guidance value
num_warmup_steps  = 0    # number of warmup steps
warmup_init_val   = 0    # the intial warmup value
num_cycles        = 0.5  # number of cosine cycles
k_decay           = 1    # k-decay for cosine curve scaling 

# group the default schedule parameters
DEFAULT_COS_PARAMS = {
    'max_val':           max_val,
    'num_steps':         num_steps,
    'min_val':           min_val,
    'num_cycles':        num_cycles,
    'k_decay':           k_decay,
    'num_warmup_steps':  num_warmup_steps,
    'warmup_init_val':   warmup_init_val,
}

def cos_harness(new_params: dict) -> dict:
    '''Creates cosine schedules with updated parameters in `new_params`
    '''
    # start from the given baseline `default_params`
    cos_params = dict(DEFAULT_COS_PARAMS)
    # update the with the new, given parameters
    cos_params.update(new_params)
    
    # return the new cosine schedule
    sched = schedules.get_cos_sched(**cos_params)
    return sched


# build the static schedule
static_sched = [baseline_g] * num_steps

# build the inverted kdecay schedule
k_sched = cos_harness({'k_decay': 0.2})
inv_k_sched = [max_val - g + min_val for g in k_sched]

# group the schedules 
scheds = {
    'cosine': {'g': inv_k_sched},
    'static': {'g': static_sched},
}
######################################
######################################

# %% app.ipynb 5
def compare_dynamic_guidance(prompt):
    '''
    Compares the default, static Classifier-free Guidance to a dynamic schedule.  

    Model and sampling paramters:
        Stable Diffusion 2 v-model
        Half-precision
        DPM++ 2M sampler, with Karras sigma schedule
        18 sampling steps
        (768 x 768) image
        Using a generic negative prompt

    Schedules:
        Static guidance with scale of 9
        Inverse kDecay (cosine variant) scheduled guidance
    '''
    # load the model
    pipeline = load_model()

    # stores the output images
    res = []

    # generate images with static and dynamic schedules
    for (name,sched) in scheds.items():
        # make the guidance norm
        gtfm = transforms.GuidanceTfm(sched)
        # generate the image
        with torch.autocast(device), torch.no_grad():
            img = pipeline.generate(prompt, gtfm, **generation_kwargs)
        # add the generated image
        res.append(name)

    # return the generated images
    return {
        'values': res,
        'label': 'Cosine vs. Static CFG'
    }

# %% app.ipynb 6
iface = gr.Interface(
    compare_dynamic_guidance,
    inputs="text",
    outputs=gr.Gallery(),
    title="Comparing image generations with dynamic Classifier-free Guidance",
)
iface.launch()