# Internals

Derivations, format rules and kernels behind the
{doc}`explanation pages <../../explanations/index>`.

| Page | Contents |
| --- | --- |
| {doc}`epg` | Extended phase graph operators and tissue terms |
| {doc}`description` | Pulseq and MRD reading |
| {doc}`kernels` | Buffer packing and fused CPU and CUDA kernels |

```{toctree}
:hidden:

epg
description
kernels
```