---
title: "symmetricLog(slopeAtZero:)"
framework: charts
role: symbol
role_heading: Type Method
path: "charts/scaletype/symmetriclog(slopeatzero:)"
---

# symmetricLog(slopeAtZero:)

A number scale where each range value y can be expressed as a symmetric log function of the domain value x, with y = a * sign(x) * log(1 + |x * slopeAtZero|) + b.

## Declaration

```swift
static func symmetricLog(slopeAtZero: Double) -> ScaleType
```

## Parameters

- `slopeAtZero`: A positive constant that controls the slope of the symmetric log function at zero.