> ## Documentation Index
> Fetch the complete documentation index at: https://docs.comfy.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Ideogram4Scheduler - ComfyUI Built-in Node Documentation

> The Ideogram 4 Scheduler node generates a sequence of sigma values (noise levels) for the diffusion sampling process, based on the Ideogram 4 reference schedule.

The Ideogram 4 Scheduler node generates a sequence of sigma values (noise levels) for the diffusion sampling process, based on the Ideogram 4 reference schedule. It creates a custom noise schedule that adapts to the image dimensions and allows fine-tuning through statistical parameters.

## Inputs

| Parameter | Description | Data Type | Required | Range |
| - | - | - | - | - |
| `steps` | The number of sampling steps to generate the schedule for (default: 20). The output contains `steps + 1` sigma values. | INT | Yes | 1 to 200 |
| `width` | The width of the image in pixels (default: 1024). The resolution relative to a 512×512 reference shifts the noise schedule. | INT | Yes | 256 to 8192 (step: 16) |
| `height` | The height of the image in pixels (default: 1024). The resolution relative to a 512×512 reference shifts the noise schedule. | INT | Yes | 256 to 8192 (step: 16) |
| `mu` | The mean parameter for the logit-normal distribution, controlling the central noise level. Combined with the resolution term to form the logSNR shift (default: 0.0). | FLOAT | Yes | -10.0 to 10.0 (step: 0.05) |
| `std` | The standard deviation parameter for the logit-normal distribution, controlling the spread of noise levels (default: 1.75). | FLOAT | Yes | 0.1 to 5.0 (step: 0.05) |

Note: The schedule is derived from a logit-normal distribution over reference time. A resolution term equal to `0.5 * log((width × height) / (512 × 512))` is added to `mu`, so larger or smaller images shift the schedule relative to a 512×512 reference at the same `mu` value.

## Outputs

| Output Name | Description | Data Type |
| - | - | - |
| `SIGMAS` | A tensor of sigma values representing the noise schedule, with length equal to `steps + 1`. The values descend from high noise to low noise, with the final value set to 0.0 for complete denoising. | SIGMAS |

> This documentation was AI-generated. If you find any errors or have suggestions for improvement, please feel free to contribute! [Edit on GitHub](https://github.com/Comfy-Org/embedded-docs/blob/main/comfyui_embedded_docs/docs/Ideogram4Scheduler/en.md)

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