HiDream Quickstart¶

In this example, we'll be training a Lycoris LoKr for HiDream, hoping to god we've got enough memory to pull it off.

A 24G GPU is likely the minimum you'll get away with without extensive block offloading and fused backward pass. A Lycoris LoKr will function just as well!

Hardware requirements¶

HiDream is a 17B total parameters with ~8B active at any given time using a learnt MoE gate to distribute its work. It uses four text encoders, and the Flux VAE.

Overall the model suffers from architectural complexity, and seems to be a derivative of Flux Dev, either by direct distillation or by continued fine-tuning, evident from some validation samples that look like they share the same weights.

Prerequisites¶

Make sure that you have python installed; SimpleTuner does well with 3.10 through 3.13.

You can check this by running:

python --version

If you don't have python 3.13 installed on Ubuntu, you can try the following:

apt -y install python3.13 python3.13-venv

Container image dependencies¶

For Vast, RunPod, and TensorDock (among others), the following will work on a CUDA 12.2-12.8 image to enable compiling of CUDA extensions:

apt -y install nvidia-cuda-toolkit

Installation¶

Install SimpleTuner via pip:

pip install 'simpletuner[cuda]'

# CUDA 13 / Blackwell users (NVIDIA B-series GPUs)
pip install 'simpletuner[cuda13]' --extra-index-url https://download.pytorch.org/whl/cu130

For manual installation or development setup, see the installation documentation.

Setting up the environment¶

To run SimpleTuner, you will need to set up a configuration file, the dataset and model directories, and a dataloader configuration file.

Configuration file¶

An experimental script, configure.py, may allow you to entirely skip this section through an interactive step-by-step configuration. It contains some safety features that help avoid common pitfalls.

Note: This doesn't configure your dataloader. You will still have to do that manually, later.

To run it:

simpletuner configure

⚠️ For users located in countries where Hugging Face Hub is not readily accessible, you should add HF_ENDPOINT=https://hf-mirror.com to your ~/.bashrc or ~/.zshrc depending on which $SHELL your system uses.

If you prefer to manually configure:

Copy config/config.json.example to config/config.json:

cp config/config.json.example config/config.json

There, you will possibly need to modify the following variables:

• model_type - Set this to lora.
• lora_type - Set this to lycoris.
• model_family - Set this to hidream.
• model_flavour - Set this to full, because dev is distilled in a way that it is not easily directly trained unless you want to go the distance and break its distillation.
• In fact, the full model is also difficult to train, but is the only one that has not been distilled.
• output_dir - Set this to the directory where you want to store your checkpoints and validation images. It's recommended to use a full path here.
• train_batch_size - 1, maybe?.
• validation_resolution - You should set this to 1024x1024 or one of HiDream's other supported resolutions.
• Other resolutions may be specified using commas to separate them: 1024x1024,1280x768,2048x2048
• validation_guidance - Use whatever you are used to selecting at inference time for HiDream; a lower value around 2.5-3.0 makes more realistic results
• validation_num_inference_steps - Use somewhere around 30

• use_ema - setting this to true will greatly help obtain a more smoothed result alongside your main trained checkpoint.

• optimizer - You can use any optimiser you are comfortable and familiar with, but we will use optimi-lion for this example.

• mixed_precision - It's recommended to set this to bf16 for the most efficient training configuration, or no (but will consume more memory and be slower).
• gradient_checkpointing - Disabling this will go the fastest, but limits your batch sizes. It is required to enable this to get the lowest VRAM usage.

Some advanced HiDream options can be set to include MoE auxiliary loss during training. By adding the MoE loss, the value will naturally be much higher than usual.

• hidream_use_load_balancing_loss - Set this to true to enable load balancing loss.
• hidream_load_balancing_loss_weight - This is the magnitude of the auxiliary loss. A value of 0.01 is the default, but you can set it to 0.1 or 0.2 for a more aggressive training run.

The impact of these options are currently unknown.

Your config.json will look something like mine by the end:

{
    "validation_torch_compile": "false",
    "validation_step_interval": 200,
    "validation_seed": 42,
    "validation_resolution": "1024x1024",
    "validation_prompt": "A photo-realistic image of a cat",
    "validation_num_inference_steps": "20",
    "validation_guidance": 3.0,
    "validation_guidance_rescale": "0.0",
    "vae_batch_size": 1,
    "train_batch_size": 1,
    "tracker_run_name": "eval_loss_test1",
    "seed": 42,
    "resume_from_checkpoint": "latest",
    "resolution": 1024,
    "resolution_type": "pixel_area",
    "report_to": "tensorboard",
    "output_dir": "output/models-hidream",
    "optimizer": "optimi-lion",
    "num_train_epochs": 0,
    "num_eval_images": 1,
    "model_type": "lora",
    "model_family": "hidream",
    "offload_during_startup": true,
    "mixed_precision": "bf16",
    "minimum_image_size": 0,
    "max_train_steps": 10000,
    "max_grad_norm": 0.01,
    "lycoris_config": "config/lycoris_config.json",
    "lr_warmup_steps": 100,
    "lr_scheduler": "constant_with_warmup",
    "lora_type": "lycoris",
    "learning_rate": "4e-5",
    "gradient_checkpointing": "true",
    "grad_clip_method": "value",
    "eval_steps_interval": 100,
    "disable_benchmark": false,
    "data_backend_config": "config/hidream/multidatabackend.json",
    "checkpoints_total_limit": 5,
    "checkpoint_step_interval": 500,
    "caption_dropout_probability": 0.0,
    "base_model_precision": "int8-quanto",
    "text_encoder_3_precision": "int8-quanto",
    "text_encoder_4_precision": "int8-quanto",
    "aspect_bucket_rounding": 2
}

ℹ️ Multi-GPU users can reference this document for information on configuring the number of GPUs to use.

ℹ️ This configuration sets the T5 (#3) and Llama (#4) text encoder precision levels to int8 to save memory for 24G cards. You can remove these options or set them to no_change if you have more memory available.

And a simple config/lycoris_config.json file - note that the FeedForward may be removed for additional training stability.

{
    "algo": "lokr",
    "multiplier": 1.0,
    "linear_dim": 16384,
    "linear_alpha": 1,
    "full_matrix": true,
    "use_scalar": true,
    "factor": 16,
    "apply_preset": {
        "target_module": [
            "Attention",
        ],
        "module_algo_map": {
            "Attention": {
                "factor": 16
            },
        }
    }
}

Setting either "use_scalar": true in config/lycoris_config.json or setting "init_lokr_norm": 1e-4 in config/config.json will speed up training considerably. Enabling both seems to slow down training slightly. Note that setting init_lokr_norm will slightly change the validation images at step 0.

Adding the FeedForward module to config/lycoris_config.json will train a much larger number of parameters, including all the experts. Training the experts seems to be rather difficult though.

An easier option is to only train the feed forward parameters outside the experts using the following config/lycoris_config.json file.

{
    "algo": "lokr",
    "multiplier": 1.0,
    "linear_dim": 16384,
    "linear_alpha": 1,
    "full_matrix": true,
    "use_scalar": true,
    "factor": 16,
    "apply_preset": {
        "name_algo_map": {
            "double_stream_blocks.*.block.attn*": {
                "factor": 16
            },
            "double_stream_blocks.*.block.ff_t*": {
                "factor": 16
            },
            "double_stream_blocks.*.block.ff_i.shared_experts*": {
                "factor": 16
            },
            "single_stream_blocks.*.block.attn*": {
                "factor": 16
            },
            "single_stream_blocks.*.block.ff_i.shared_experts*": {
                "factor": 16
            }
        },
        "use_fnmatch": true
    }
}

Advanced Experimental Features¶

{
  "nickname": "the prompt goes here",
  "another_nickname": "another prompt goes here"
}

  "--user_prompt_library": "config/user_prompt_library.json",

{
    "anime_<token>": "a breathtaking anime-style portrait of <token>, capturing her essence with vibrant colors and expressive features",
    "chef_<token>": "a high-quality, detailed photograph of <token> as a sous-chef, immersed in the art of culinary creation",
    "just_<token>": "a lifelike and intimate portrait of <token>, showcasing her unique personality and charm",
    "cinematic_<token>": "a cinematic, visually stunning photo of <token>, emphasizing her dramatic and captivating presence",
    "elegant_<token>": "an elegant and timeless portrait of <token>, exuding grace and sophistication",
    "adventurous_<token>": "a dynamic and adventurous photo of <token>, captured in an exciting, action-filled moment",
    "mysterious_<token>": "a mysterious and enigmatic portrait of <token>, shrouded in shadows and intrigue",
    "vintage_<token>": "a vintage-style portrait of <token>, evoking the charm and nostalgia of a bygone era",
    "artistic_<token>": "an artistic and abstract representation of <token>, blending creativity with visual storytelling",
    "futuristic_<token>": "a futuristic and cutting-edge portrayal of <token>, set against a backdrop of advanced technology",
    "woman": "a beautifully crafted portrait of a woman, highlighting her natural beauty and unique features",
    "man": "a powerful and striking portrait of a man, capturing his strength and character",
    "boy": "a playful and spirited portrait of a boy, capturing youthful energy and innocence",
    "girl": "a charming and vibrant portrait of a girl, emphasizing her bright personality and joy",
    "family": "a heartwarming and cohesive family portrait, showcasing the bonds and connections between loved ones"
}

Stable evaluation loss¶

If you wish to use stable MSE loss to score the model's performance, see this document for information on configuring and interpreting evaluation loss.

Validation previews¶

SimpleTuner supports streaming intermediate validation previews during generation using Tiny AutoEncoder models. This allows you to see validation images being generated step-by-step in real-time via webhook callbacks.

To enable:

{
  "validation_preview": true,
  "validation_preview_steps": 1
}

Requirements: - Webhook configuration - Validation enabled

Set validation_preview_steps to a higher value (e.g., 3 or 5) to reduce Tiny AutoEncoder overhead. With validation_num_inference_steps=20 and validation_preview_steps=5, you'll receive preview images at steps 5, 10, 15, and 20.

Flow schedule shifting¶

Flow-matching models such as OmniGen, Sana, Flux, and SD3 have a property called "shift" that allows us to shift the trained portion of the timestep schedule using a simple decimal value.

The full model is trained with a value of 3.0 and dev used 6.0.

In practice, using such a high shift value tends to destroy either model. A value of 1.0 is a good starting point, but may move the model too little, and 3.0 may be too high.

Auto-shift¶

A commonly-recommended approach is to follow several recent works and enable resolution-dependent timestep shift, --flow_schedule_auto_shift which uses higher shift values for larger images, and lower shift values for smaller images. This results in stable but potentially mediocre training results.

Manual specification¶

Thanks to General Awareness from Discord for the following examples

When using a --flow_schedule_shift value of 0.1 (a very low value), only the finer details of the image are affected:

When using a --flow_schedule_shift value of 4.0 (a very high value), the large compositional features and potentially colour space of the model becomes impacted:

Dataset considerations¶

It's crucial to have a substantial dataset to train your model on. There are limitations on the dataset size, and you will need to ensure that your dataset is large enough to train your model effectively. Note that the bare minimum dataset size is train_batch_size * gradient_accumulation_steps as well as more than vae_batch_size. The dataset will not be useable if it is too small.

ℹ️ With few enough images, you might see a message no images detected in dataset - increasing the repeats value will overcome this limitation.

Depending on the dataset you have, you will need to set up your dataset directory and dataloader configuration file differently. In this example, we will be using pseudo-camera-10k as the dataset.

Create a --data_backend_config (config/multidatabackend.json) document containing this:

[
  {
    "id": "pseudo-camera-10k-hidream",
    "type": "local",
    "crop": true,
    "crop_aspect": "square",
    "crop_style": "center",
    "resolution": 1024,
    "minimum_image_size": 1024,
    "maximum_image_size": 1024,
    "target_downsample_size": 1024,
    "resolution_type": "pixel_area",
    "cache_dir_vae": "cache/vae/hidream/pseudo-camera-10k",
    "instance_data_dir": "datasets/pseudo-camera-10k",
    "disabled": false,
    "skip_file_discovery": "",
    "caption_strategy": "filename",
    "metadata_backend": "discovery",
    "repeats": 0,
    "is_regularisation_data": true
  },
  {
    "id": "dreambooth-subject",
    "type": "local",
    "crop": false,
    "resolution": 1024,
    "minimum_image_size": 1024,
    "maximum_image_size": 1024,
    "target_downsample_size": 1024,
    "resolution_type": "pixel_area",
    "cache_dir_vae": "cache/vae/hidream/dreambooth-subject",
    "instance_data_dir": "datasets/dreambooth-subject",
    "caption_strategy": "instanceprompt",
    "instance_prompt": "the name of your subject goes here",
    "metadata_backend": "discovery",
    "repeats": 1000
  },
  {
    "id": "text-embeds",
    "type": "local",
    "dataset_type": "text_embeds",
    "default": true,
    "cache_dir": "cache/text/hidream",
    "disabled": false,
    "write_batch_size": 128
  }
]

ℹ️ Use caption_strategy=textfile if you have .txt files containing captions. See caption_strategy options and requirements in DATALOADER.md.

Then, create a datasets directory:

mkdir -p datasets
pushd datasets
    huggingface-cli download --repo-type=dataset bghira/pseudo-camera-10k --local-dir=pseudo-camera-10k
    mkdir dreambooth-subject
    # place your images into dreambooth-subject/ now
popd

This will download about 10k photograph samples to your datasets/pseudo-camera-10k directory, which will be automatically created for you.

Your Dreambooth images should go into the datasets/dreambooth-subject directory.

Login to WandB and Huggingface Hub¶

You'll want to login to WandB and HF Hub before beginning training, especially if you're using --push_to_hub and --report_to=wandb.

If you're going to be pushing items to a Git LFS repository manually, you should also run git config --global credential.helper store

Run the following commands:

wandb login

and

huggingface-cli login

Follow the instructions to log in to both services.

Executing the training run¶

From the SimpleTuner directory, you have several options to start training:

Option 1 (Recommended - pip install):

pip install 'simpletuner[cuda]'

# CUDA 13 / Blackwell users (NVIDIA B-series GPUs)
pip install 'simpletuner[cuda13]' --extra-index-url https://download.pytorch.org/whl/cu130

simpletuner train

Option 2 (Git clone method):

simpletuner train

Option 3 (Legacy method - still works):

./train.sh

This will begin the text embed and VAE output caching to disk.

For more information, see the dataloader and tutorial documents.

Running inference on the LoKr afterward¶

Since it's a new model, the example will need some adjustment to work. Here's a functioning example:

import torch
from helpers.models.hidream.pipeline import HiDreamImagePipeline
from helpers.models.hidream.transformer import HiDreamImageTransformer2DModel
from lycoris import create_lycoris_from_weights
from transformers import PreTrainedTokenizerFast, LlamaForCausalLM

llama_repo = "unsloth/Meta-Llama-3.1-8B-Instruct"
model_id = 'HiDream-ai/HiDream-I1-Dev'
adapter_repo_id = 'bghira/hidream5m-photo-1mp-Prodigy'
adapter_filename = 'pytorch_lora_weights.safetensors'

tokenizer_4 = PreTrainedTokenizerFast.from_pretrained(
    llama_repo,
)
text_encoder_4 = LlamaForCausalLM.from_pretrained(
    llama_repo,
    output_hidden_states=True,
    output_attentions=True,
    torch_dtype=torch.bfloat16,
)

def download_adapter(repo_id: str):
    import os
    from huggingface_hub import hf_hub_download
    adapter_filename = "pytorch_lora_weights.safetensors"
    cache_dir = os.environ.get('HF_PATH', os.path.expanduser('~/.cache/huggingface/hub/models'))
    cleaned_adapter_path = repo_id.replace("/", "_").replace("\\", "_").replace(":", "_")
    path_to_adapter = os.path.join(cache_dir, cleaned_adapter_path)
    path_to_adapter_file = os.path.join(path_to_adapter, adapter_filename)
    os.makedirs(path_to_adapter, exist_ok=True)
    hf_hub_download(
        repo_id=repo_id, filename=adapter_filename, local_dir=path_to_adapter
    )

    return path_to_adapter_file

adapter_file_path = download_adapter(repo_id=adapter_repo_id)
transformer = HiDreamImageTransformer2DModel.from_pretrained(model_id, torch_dtype=torch.bfloat16, subfolder="transformer")
pipeline = HiDreamImagePipeline.from_pretrained(
    model_id,
    torch_dtype=torch.bfloat16,
    tokenizer_4=tokenizer_4,
    text_encoder_4=text_encoder_4,
    transformer=transformer,
)
lora_scale = 1.0
wrapper, _ = create_lycoris_from_weights(lora_scale, adapter_file_path, pipeline.transformer)
wrapper.merge_to()

prompt = "Place your test prompt here."
negative_prompt = 'ugly, cropped, blurry, low-quality, mediocre average'

## Optional: quantise the model to save on vram.
## Note: The model was quantised during training, and so it is recommended to do the same during inference time.
from optimum.quanto import quantize, freeze, qint8
quantize(pipeline.transformer, weights=qint8)
freeze(pipeline.transformer)

pipeline.to('cuda' if torch.cuda.is_available() else 'mps' if torch.backends.mps.is_available() else 'cpu') # the pipeline is already in its target precision level
t5_embeds, llama_embeds, negative_t5_embeds, negative_llama_embeds, pooled_embeds, negative_pooled_embeds = pipeline.encode_prompt(
    prompt=prompt, prompt_2=prompt, prompt_3=prompt, prompt_4=prompt, num_images_per_prompt=1
)
# We'll nuke the text encoders to save memory.
pipeline.text_encoder.to("meta")
pipeline.text_encoder_2.to("meta")
pipeline.text_encoder_3.to("meta")
pipeline.text_encoder_4.to("meta")
model_output = pipeline(
    t5_prompt_embeds=t5_embeds,
    llama_prompt_embeds=llama_embeds,
    pooled_prompt_embeds=pooled_embeds,
    negative_t5_prompt_embeds=negative_t5_embeds,
    negative_llama_prompt_embeds=negative_llama_embeds,
    negative_pooled_prompt_embeds=negative_pooled_embeds,
    num_inference_steps=30,
    generator=torch.Generator(device='cuda' if torch.cuda.is_available() else 'mps' if torch.backends.mps.is_available() else 'cpu').manual_seed(42),
    width=1024,
    height=1024,
    guidance_scale=3.2,
).images[0]

model_output.save("output.png", format="PNG")

Notes & troubleshooting tips¶

Lowest VRAM config¶

The lowest VRAM HiDream configuration is about 20-22G:

• OS: Ubuntu Linux 24
• GPU: A single NVIDIA CUDA device (10G, 12G)
• System memory: 50G of system memory approximately (could be more, could be less)
• Base model precision:
• For Apple and AMD systems, int8-quanto (or fp8-torchao, int8-torchao all follow similar memory use profiles)
  • int4-quanto works as well, but you might have lower accuracy / worse results
• For NVIDIA systems, nf4-bnb is reported to work well, but will be slower than int8-quanto
• Optimiser: Lion 8Bit Paged, bnb-lion8bit-paged
• Resolution: 1024px
• Batch size: 1, zero gradient accumulation steps
• DeepSpeed: disabled / unconfigured
• PyTorch: 2.7+
• Using --quantize_via=cpu to avoid outOfMemory error during startup on <=16G cards.
• Enable --gradient_checkpointing
• Use a tiny LoRA or Lycoris configuration (eg. LoRA rank 1 or Lokr factor 25)
• Setting the environment variable PYTORCH_CUDA_ALLOC_CONF=expandable_segments:True helps minimize VRAM usage when training multiple aspect ratios.

NOTE: Pre-caching of VAE embeds and text encoder outputs may use more memory and still OOM. VAE tiling and slicing are enabled by default. If you see OOM, try enabling offload_during_startup=true; otherwise, you might just be out of luck.

Speed was approximately 3 iterations per second on an NVIDIA 4090 using Pytorch 2.7 and CUDA 12.8

Masked loss¶

If you are training a subject or style and would like to mask one or the other, see the masked loss training section of the Dreambooth guide.

Quantisation¶

Though int8 is the best option for speed/quality vs memory trade-offs, nf4 and int4 are also available. int4 is not recommended for HiDream, as it may lead to worse results, but with long enough training, you would end up with a somewhat-capable int4 model.

Learning rates¶

LoRA (--lora_type=standard)¶

• Higher learning rates around 4e-4 work better for smaller LoRAs (rank-1 through rank-8)
• Lower learning rates around 6e-5 work better for larger LoRAs (rank-64 through rank-256)
• Setting lora_alpha differently from lora_rank is not supported due to Diffusers limitations, unless you know what you're doing in inference tools afterwards.
• How to use it later for inference is out of scope, but setting lora_alpha to 1.0 would allow keeping the learning rate the same across all lora ranks.

LoKr (--lora_type=lycoris)¶

• Mild learning rates are better for LoKr (1e-4 with AdamW, 2e-5 with Lion)
• Other algo need more exploration.
• Prodigy seems to be a good choice for LoRA or LoKr, but might over-estimate the required learning rate and smoothen the skin.

Image artifacts¶

HiDream has an unknown response to image artifacts, though it uses the Flux VAE, and has similar fine-details limitations.

The most prevalent problem is using too-high of a learning rate and/or too-low of a batch size. This can cause the model to produce images with artifacts, such as smooth skin, blurriness, and pixelation.

Aspect bucketing¶

Initially, the model did not respond very well to aspect buckets, but the implementation has been improved by the community.

Multiple-resolution training¶

The model can be initially trained at a lower resolution such as 512px to speed up training, but it's not certain whether the model will generalise very well to higher resolutions. Sequentially training first on 512px, and then 1024px, is probably the best approach.

It is a good idea to enable --flow_schedule_auto_shift when training resolutions different from 1024px. Lower resolutions use less VRAM, allowing higher batch sizes to be used.

Full-rank tuning¶

DeepSpeed will use a LOT of system memory with HiDream, but full tuning seems to work just fine on a very-large system.

Lycoris LoKr is recommended in lieu of full-rank tuning, as it is more stable and has a lower memory footprint.

PEFT LoRA is useful for simpler styles, but harder to maintain fine details with.