# SigmoidFunction class

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
[IoId("00000000-51a0-4b10-9c31-0a1b2c3d5e01")]
public sealed class SigmoidFunction : FunctionWithCaching
```

A bounded, monotonic sigmoid (S-curve) transitioning from a low asymptote to a high asymptote. The curve is antisymmetric about its inflection point, which sits at the mid-level halfway between the two asymptotes.

The steepness is given by the slope at the inflection. A negative slope produces a falling sigmoid. Every [SigmoidKind](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidkind.md) shares the same asymptotes, inflection and inflection-slope for a given set of parameters, so switching variants keeps those anchors fixed and changes only the tail behaviour.

## Constructors

- [SigmoidFunction](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/ctor.md): (3 overloads) Create a default logistic sigmoid rising from 0 to 1 with its inflection at the origin.

## Properties

- [Centre](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/centre.md): Gets the inflection x-coordinate.
- [High](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/high.md): Gets the high asymptote.
- [Kind](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/kind.md): Gets the sigmoid variant.
- [Low](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/low.md): Gets the low asymptote.
- [MidLevel](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/midlevel.md): Gets the mid-level, y at the inflection point.
- [Scale](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/scale.md): Gets the signed horizontal scale of the normalised profile. Negative = falling.
- [SlopeAtCentre](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/slopeatcentre.md): Gets the slope of the curve at the inflection point.
- [Ui](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/ui.md): Gets a UI object for modifying this function. This property may return null, not all functions must be editable.

## Methods

- [DomainEstimate](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/domainestimate.md)
- [EmitDerivative](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/emitderivative.md)
- [FromSlope](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/fromslope.md): (static) Create a sigmoid from its inflection slope rather than its internal scale. The scale is solved so the curve has exactly this slope at the centre, whatever the variant.
- [Store](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/store.md)
- [Y](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.standard.sigmoidfunction/y.md)

## Inherited Members

- From [FunctionWithCaching](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.functionwithcaching.md): [Derivative](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.functionwithcaching/derivative.md), [Integral](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.functionwithcaching/integral.md), [Nomen](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.functionwithcaching/nomen.md), [Notation](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.functionwithcaching/notation.md), [EmitIntegral](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.functionwithcaching/emitintegral.md)
- From [Function](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function.md): [Asymptotes](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function/asymptotes.md), [AutoCoDomain](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function/autocodomain.md), [Holes](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function/holes.md), [Integrate](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function/integrate.md), [Poles](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function/poles.md), [YYYY](https://developer.rhino3d.com/api/gh2/type/grasshopper2.types.functions.function/yyyy.md)