# SigmoidKind enum

Namespace: [Grasshopper2.Types.Functions.Standard](https://developer.rhino3d.com/api/gh2/namespace/grasshopper2.types.functions.standard.md) · Assembly: [Grasshopper2](https://developer.rhino3d.com/api/gh2/assembly/grasshopper2.md)

```cs
public enum SigmoidKind
```

The family of common sigmoid (S-shaped) curves. All variants share the same anchors — an inflection point and a tangent slope — and differ only in how quickly they saturate towards their asymptotes (their tail behaviour).

## Values

| Name | Value | Description |
| --- | --- | --- |
| Logistic | 0 | Logistic curve 1/(1+e⁻ˣ). Exponential tails. |
| Arctangent | 1 | Arctangent. Heavy, algebraic (~1/x) tails. |
| ErrorFunction | 2 | Error function (the Normal CDF). Gaussian tails — the fastest saturation. |
| Algebraic | 3 | Algebraic sigmoid x/(1+\|x\|). Cheap, algebraic tails. |