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# CogView4

> [!TIP]
> Make sure to check out the Schedulers [guide](../../using-diffusers/schedulers) to learn how to explore the tradeoff between scheduler speed and quality, and see the [reuse components across pipelines](../../using-diffusers/loading#reuse-a-pipeline) section to learn how to efficiently load the same components into multiple pipelines.

This pipeline was contributed by [zRzRzRzRzRzRzR](https://github.com/zRzRzRzRzRzRzR). The original codebase can be found [here](https://huggingface.co/THUDM). The original weights can be found under [hf.co/THUDM](https://huggingface.co/THUDM).

## CogView4Pipeline[[diffusers.CogView4Pipeline]]

#### diffusers.CogView4Pipeline[[diffusers.CogView4Pipeline]]

```python
diffusers.CogView4Pipeline(tokenizer: AutoTokenizer, text_encoder: GlmModel, vae: AutoencoderKL, transformer: CogView4Transformer2DModel, scheduler: FlowMatchEulerDiscreteScheduler)
```

[Source](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/cogview4/pipeline_cogview4.py#L137)

**Parameters:**

vae ([AutoencoderKL](/docs/diffusers/main/en/api/models/autoencoderkl#diffusers.AutoencoderKL)) : Variational Auto-Encoder (VAE) Model to encode and decode images to and from latent representations.

text_encoder (`GLMModel`) : Frozen text-encoder. CogView4 uses [glm-4-9b-hf](https://huggingface.co/THUDM/glm-4-9b-hf).

tokenizer (`PreTrainedTokenizer`) : Tokenizer of class [PreTrainedTokenizer](https://huggingface.co/docs/transformers/main/en/main_classes/tokenizer#transformers.PreTrainedTokenizer).

transformer ([CogView4Transformer2DModel](/docs/diffusers/main/en/api/models/cogview4_transformer2d#diffusers.CogView4Transformer2DModel)) : A text conditioned `CogView4Transformer2DModel` to denoise the encoded image latents.

scheduler ([SchedulerMixin](/docs/diffusers/main/en/api/schedulers/overview#diffusers.SchedulerMixin)) : A scheduler to be used in combination with `transformer` to denoise the encoded image latents.

Pipeline for text-to-image generation using CogView4.

This model inherits from [DiffusionPipeline](/docs/diffusers/main/en/api/pipelines/overview#diffusers.DiffusionPipeline). Check the superclass documentation for the generic methods the
library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.)

#### __call__[[diffusers.CogView4Pipeline.__call__]]

```python
__call__(prompt: str | list[str] | None = None, negative_prompt: str | list[str] | None = None, height: int | None = None, width: int | None = None, num_inference_steps: int = 50, timesteps: list[int] | None = None, sigmas: list[float] | None = None, guidance_scale: float = 5.0, num_images_per_prompt: int = 1, generator: typing.Union[torch.Generator, list[torch.Generator], NoneType] = None, latents: typing.Optional[torch.FloatTensor] = None, prompt_embeds: typing.Optional[torch.FloatTensor] = None, negative_prompt_embeds: typing.Optional[torch.FloatTensor] = None, original_size: tuple[int, int] | None = None, crops_coords_top_left: tuple = (0, 0), output_type: str = 'pil', return_dict: bool = True, attention_kwargs: dict[str, typing.Any] | None = None, callback_on_step_end: typing.Union[typing.Callable[[int, int], NoneType], diffusers.callbacks.PipelineCallback, diffusers.callbacks.MultiPipelineCallbacks, NoneType] = None, callback_on_step_end_tensor_inputs: list = ['latents'], max_sequence_length: int = 1024)
```

[Source](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/cogview4/pipeline_cogview4.py#L402)

**Parameters:**

prompt (`str` or `list[str]`, *optional*) : The prompt or prompts to guide the image generation. If not defined, one has to pass `prompt_embeds`.

negative_prompt (`str` or `list[str]`, *optional*) : The prompt or prompts not to guide the image generation. If not defined, one has to pass `negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is less than `1`).

height (`int`, *optional*, defaults to self.transformer.config.sample_size * self.vae_scale_factor) : The height in pixels of the generated image. If not provided, it is set to 1024.

width (`int`, *optional*, defaults to self.transformer.config.sample_size * self.vae_scale_factor) : The width in pixels of the generated image. If not provided it is set to 1024.

num_inference_steps (`int`, *optional*, defaults to `50`) : The number of denoising steps. More denoising steps usually lead to a higher quality image at the expense of slower inference.

timesteps (`list[int]`, *optional*) : Custom timesteps to use for the denoising process with schedulers which support a `timesteps` argument in their `set_timesteps` method. If not defined, the default behavior when `num_inference_steps` is passed will be used. Must be in descending order.

sigmas (`list[float]`, *optional*) : Custom sigmas to use for the denoising process with schedulers which support a `sigmas` argument in their `set_timesteps` method. If not defined, the default behavior when `num_inference_steps` is passed will be used.

guidance_scale (`float`, *optional*, defaults to `5.0`) : Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://huggingface.co/papers/2207.12598). `guidance_scale` is defined as `w` of equation 2. of [Imagen Paper](https://huggingface.co/papers/2205.11487). Guidance scale is enabled by setting `guidance_scale > 1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`, usually at the expense of lower image quality.

num_images_per_prompt (`int`, *optional*, defaults to `1`) : The number of images to generate per prompt.

generator (`torch.Generator` or `list[torch.Generator]`, *optional*) : One or a list of [torch generator(s)](https://pytorch.org/docs/stable/generated/torch.Generator.html) to make generation deterministic.

latents (`torch.FloatTensor`, *optional*) : Pre-generated noisy latents, sampled from a Gaussian distribution, to be used as inputs for image generation. Can be used to tweak the same generation with different prompts. If not provided, a latents tensor will be generated by sampling using the supplied random `generator`.

prompt_embeds (`torch.FloatTensor`, *optional*) : Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not provided, text embeddings will be generated from `prompt` input argument.

negative_prompt_embeds (`torch.FloatTensor`, *optional*) : Pre-generated negative text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not provided, negative_prompt_embeds will be generated from `negative_prompt` input argument.

original_size (`tuple[int]`, *optional*, defaults to (1024, 1024)) : If `original_size` is not the same as `target_size` the image will appear to be down- or upsampled. `original_size` defaults to `(height, width)` if not specified. Part of SDXL's micro-conditioning as explained in section 2.2 of [https://huggingface.co/papers/2307.01952](https://huggingface.co/papers/2307.01952).

crops_coords_top_left (`tuple[int]`, *optional*, defaults to (0, 0)) : `crops_coords_top_left` can be used to generate an image that appears to be "cropped" from the position `crops_coords_top_left` downwards. Favorable, well-centered images are usually achieved by setting `crops_coords_top_left` to (0, 0). Part of SDXL's micro-conditioning as explained in section 2.2 of [https://huggingface.co/papers/2307.01952](https://huggingface.co/papers/2307.01952).

output_type (`str`, *optional*, defaults to `"pil"`) : The output format of the generate image. Choose between [PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`.

return_dict (`bool`, *optional*, defaults to `True`) : Whether or not to return a `~pipelines.stable_diffusion_xl.StableDiffusionXLPipelineOutput` instead of a plain tuple.

attention_kwargs (`dict`, *optional*) : A kwargs dictionary that if specified is passed along to the `AttentionProcessor` as defined under `self.processor` in [diffusers.models.attention_processor](https://github.com/huggingface/diffusers/blob/main/src/diffusers/models/attention_processor.py).

callback_on_step_end (`Callable`, *optional*) : A function that calls at the end of each denoising steps during the inference. The function is called with the following arguments: `callback_on_step_end(self: DiffusionPipeline, step: int, timestep: int, callback_kwargs: Dict)`. `callback_kwargs` will include a list of all tensors as specified by `callback_on_step_end_tensor_inputs`.

callback_on_step_end_tensor_inputs (`list`, *optional*) : The list of tensor inputs for the `callback_on_step_end` function. The tensors specified in the list will be passed as `callback_kwargs` argument. You will only be able to include variables listed in the `._callback_tensor_inputs` attribute of your pipeline class.

max_sequence_length (`int`, defaults to `224`) : Maximum sequence length in encoded prompt. Can be set to other values but may lead to poorer results.

**Returns:** `~pipelines.cogview4.pipeline_CogView4.CogView4PipelineOutput` or `tuple`

`~pipelines.cogview4.pipeline_CogView4.CogView4PipelineOutput` if `return_dict` is True, otherwise a
`tuple`. When returning a tuple, the first element is a list with the generated images.

Function invoked when calling the pipeline for generation.

Examples:
```python
>>> import torch
>>> from diffusers import CogView4Pipeline

>>> pipe = CogView4Pipeline.from_pretrained("THUDM/CogView4-6B", torch_dtype=torch.bfloat16)
>>> pipe.to("cuda")

>>> prompt = "A photo of an astronaut riding a horse on mars"
>>> image = pipe(prompt).images[0]
>>> image.save("output.png")
```

#### encode_prompt[[diffusers.CogView4Pipeline.encode_prompt]]

```python
encode_prompt(prompt: str | list[str], negative_prompt: str | list[str] | None = None, do_classifier_free_guidance: bool = True, num_images_per_prompt: int = 1, prompt_embeds: typing.Optional[torch.Tensor] = None, negative_prompt_embeds: typing.Optional[torch.Tensor] = None, device: typing.Optional[torch.device] = None, dtype: typing.Optional[torch.dtype] = None, max_sequence_length: int = 1024)
```

[Source](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/cogview4/pipeline_cogview4.py#L221)

**Parameters:**

prompt (`str` or `list[str]`, *optional*) : prompt to be encoded

negative_prompt (`str` or `list[str]`, *optional*) : The prompt or prompts not to guide the image generation. If not defined, one has to pass `negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is less than `1`).

do_classifier_free_guidance (`bool`, *optional*, defaults to `True`) : Whether to use classifier free guidance or not.

num_images_per_prompt (`int`, *optional*, defaults to 1) : Number of images that should be generated per prompt. torch device to place the resulting embeddings on

prompt_embeds (`torch.Tensor`, *optional*) : Pre-generated text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not provided, text embeddings will be generated from `prompt` input argument.

negative_prompt_embeds (`torch.Tensor`, *optional*) : Pre-generated negative text embeddings. Can be used to easily tweak text inputs, *e.g.* prompt weighting. If not provided, negative_prompt_embeds will be generated from `negative_prompt` input argument.

device : (`torch.device`, *optional*): torch device

dtype : (`torch.dtype`, *optional*): torch dtype

max_sequence_length (`int`, defaults to `1024`) : Maximum sequence length in encoded prompt. Can be set to other values but may lead to poorer results.

Encodes the prompt into text encoder hidden states.

## CogView4PipelineOutput[[diffusers.pipelines.cogview4.pipeline_output.CogView4PipelineOutput]]

#### diffusers.pipelines.cogview4.pipeline_output.CogView4PipelineOutput[[diffusers.pipelines.cogview4.pipeline_output.CogView4PipelineOutput]]

```python
diffusers.pipelines.cogview4.pipeline_output.CogView4PipelineOutput(images: list[PIL.Image.Image] | numpy.ndarray)
```

[Source](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/cogview4/pipeline_output.py#L10)

**Parameters:**

images (`list[PIL.Image.Image]` or `np.ndarray`) : list of denoised PIL images of length `batch_size` or numpy array of shape `(batch_size, height, width, num_channels)`. PIL images or numpy array present the denoised images of the diffusion pipeline.

Output class for CogView3 pipelines.