# Job: Simulate Data (GPU)

## Description

This job generates simulated particles from an input volume by projecting, CTF corrupting, and adding noise. This is an advanced job type that is not intended for common workflows.

## Input

* Volume with `map` result
* Mask (optional)
* Particles (optional)

## Common Parameters

### Simulation Parameters

* `Number of particles to generate`: Specifies the number of particles to simulate. 
* `Noise Model`: Either "white", or "none". A white noise model will add Gaussian white noise to the simulated particles at the specified signal to noise ratio. Set to "none" for no noise.

### CTF Parameters

* `Read CTF from input particles`: If set to True and input particles are connected, the ctf information will be read from the particles and applied to the simulated images.

### Alignment Parameters

* `Read alignments from input particles`: If set to True and the input particles are connected, the 3D alignments will be read from the particles and used to generate the simulated images.
* `Standard deviation of shift magnitude`: This specifies the standard deviation of the normal distribution that shifts are sampled from. The distribution is centered at the origin.

## Output

* Particles with `blob`, `ctf`, and `alignments3D`

## Example Images

<figure><img src="https://1916621962-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M7DGv3GkRvGGpbVPCgg%2Fuploads%2Fl5AWT3SjGesN285OSeWy%2Fv4-4-0-simulator-volume-example-0.png?alt=media&#x26;token=23e91700-8ce1-47f3-84fd-20ff54f7d1a0" alt=""><figcaption><p>Example input volume to the Simulator Job.</p></figcaption></figure>

<figure><img src="https://1916621962-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-M7DGv3GkRvGGpbVPCgg%2Fuploads%2F1Cf6nlZcSwbkpJUPnHE9%2Fv4-4-0-simulator-example-0.png?alt=media&#x26;token=ba8c743e-53bc-4916-a66e-c6d51073067e" alt=""><figcaption><p>Example simulated particle images with white noise.</p></figcaption></figure>