# shz_invf_fsrra

Source: https://sh4zam.com/api/scalar/shz_invf_fsrra/

> Takes the inverse of x using a very fast approximation, returning a positive result

```c
SHZ_INLINE float shz_invf_fsrra(float x) SHZ_NOEXCEPT;
```

Takes the inverse of `x` using a very fast approximation, returning a positive result.

## Parameters

| Name | Type | Description |
| --- | --- | --- |
| `x` | `float` |  |

## Returns

`float`

## Naming and requirements

- `_fsrra`: Uses `FSRRA` (fast approximate 1/sqrt(x)). The argument or denominator must be positive. Faster, less precise. ([Naming and Suffixes](https://sh4zam.com/concepts/naming-and-suffixes/))

## Availability

- **C++ equivalent:** [`shz::invf_fsrra`](https://sh4zam.com/api/cpp/#shzinvf_fsrra)
- **Type-generic form:** none
- **Back-ends:** SH4: shared C implementation · SW: portable C · SPU: shared C implementation
- **Defined in:** [`sh4zam/shz_scalar.h:289`](https://github.com/gyrovorbis/sh4zam/blob/ba1e30c88d49df0311870b229e1dd860ef26c477/include/sh4zam/shz_scalar.h#L289)
- **Module:** [Scalar](https://sh4zam.com/api/scalar/), section "FSRRA"