(ref_mesh)=

# Mesh Utilities

## Mesh Class

```{eval-rst}
.. currentmodule:: sgio
```

```{eval-rst}
.. autosummary::
   :toctree: _temp

   SGMesh
```

## Node and Element Numbering

The numbering module provides validation and utilities for node and element numbering.

### Validation Functions

```{eval-rst}
.. currentmodule:: sgio
```

```{eval-rst}
.. autosummary::
   :toctree: _temp

   validate_node_ids
   validate_element_ids
```

### Utility Functions

```{eval-rst}
.. currentmodule:: sgio
```

```{eval-rst}
.. autosummary::
   :toctree: _temp

   get_node_id_mapping
   ensure_node_ids
   ensure_element_ids
   check_duplicate_ids
   check_forbidden_ids
   renumber_elements
   auto_renumber_for_format
```

### Format Numbering Requirements

Each target format declares its node/element numbering constraints. The writers
consult this registry and adjust numbering automatically, so explicit
renumbering is normally unnecessary.

```{eval-rst}
.. currentmodule:: sgio
```

```{eval-rst}
.. autosummary::
   :toctree: _temp

   FormatNumberingRequirements
   normalize_format_name
   get_numbering_requirements
```

Two module-level tables back these functions:

- `sgio.FORMAT_ALIASES` — maps format aliases to their canonical name (for
  example `'sc'` to `'swiftcomp'`). {func}`normalize_format_name` applies this
  mapping.
- `sgio.FORMAT_REQUIREMENTS` — maps each canonical format name to its
  {class}`FormatNumberingRequirements`. {func}`get_numbering_requirements`
  looks up this table, resolving aliases first.


## Mesh Validation Functions

```{eval-rst}
.. currentmodule:: sgio.core.mesh
```

```{eval-rst}
.. autosummary::
   :toctree: _temp

   check_cell_ordering
   fix_cell_ordering
   check_isolated_nodes
```