# \antidiagonalmatrix

Used to generate an anti-diagonal matrix from a comma-separated list of entries, typically inside \mqty{...} or related physics matrix macros.

https://texform.dev/latex/commands/antidiagonalmatrix

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Physics: matrices](https://texform.dev/latex/topics/physics-matrices) |
| Packages | physics |
| Allowed mode | math |
| Tags |  |
| Commonality | low |
| Kind | prefix |

## Syntax

### physics

Argument specification: `g`

Used to generate an anti-diagonal matrix from a comma-separated list of entries, typically inside \mqty{...} or related physics matrix macros.

## Examples

```latex
\antidiagonalmatrix
```

[Open in Playground](https://play.texform.dev/?input=%5Cantidiagonalmatrix)

```latex
\mqty{\antidiagonalmatrix{a,b}}
```

[Open in Playground](https://play.texform.dev/?input=%5Cmqty%7B%5Cantidiagonalmatrix%7Ba%2Cb%7D%7D)

## Renderer support

| Package | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- |
| physics | full | none | full |

## In TeXForm

TeXForm parses this entry as prefix syntax; the package determines its argument specification.

### Expands to (physics)

```latex
\antidiagonalmatrix{#1,#2}
```

→

```latex
& \mqty{#1} \\ \mqty{#2}
```

Expands to an anti-diagonal arrangement of \mqty-wrapped elements separated by & and \\.

### [physics/antidiagonalmatrix-to-admat](https://texform.dev/rules/physics/antidiagonalmatrix-to-admat)

Collapse antidiagonalmatrix to the shorter admat helper.

Level: authoring. Fidelity: render.

```latex
\antidiagonalmatrix{#1}
```

→

```latex
\admat{#1}
```

```latex
J=\mqty(\antidiagonalmatrix{1,-1})
```

→

```latex
J=\mqty(\admat{1,-1})
```

## Equivalent forms

```latex
\admat{...}
```

exact. Short alias provided by the physics package with identical parsing and anti-diagonal behavior.

## See also

- [\\admat](https://texform.dev/latex/commands/admat)
- [\\diagonalmatrix](https://texform.dev/latex/commands/diagonalmatrix)
- [\\dmat](https://texform.dev/latex/commands/dmat)

## Test cases

### physics

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| \antidiagonalmatrix | Positive: baseline | Pass | Fail | Pass |
| \antidiagonalmatrix{a} | Positive: vary:g[0] | Pass | Fail | Pass |