# Logarithm

## Overview

![The Logarithm Node.](https://1582035224-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MIspkFTPkuGkv4UgQGs-3848250649%2Fuploads%2Fgit-blob-f17b8950dc32fa078996245bbdf57009011a8b2b%2Fnode-logarithm.png?alt=media)

**Logarithm** calculates the *logarithm* of a number in a chosen base.

This is the inverse function of the [**Power Node**](https://docs.incari.com/incari-studio/2021.3/toolbox/math/power). Rather than taking a *base* value, raising it to the power of an *exponent*, and returning the *power*, it takes the *base* value, along with the *power*, and returns the *exponent*.

## Attributes

### Inputs

| Attribute | Type          | Description                                                                                                                                                                          |
| --------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `Base`    | **Drop-down** | A selection of common bases used in logarithm functions, which are: `2` (binary), `e` (natural), or `10` (common), as well as a `Custom` option, for defining a custom *base* value. |

### Default

| Attribute                                                                     | Type      | Description            |
| ----------------------------------------------------------------------------- | --------- | ---------------------- |
| `Base Value` *(Made available by the `Base`* ***Attribute** set to `Custom`)* | **Float** | A custom *base* value. |

## Inputs

| Input             | Type      | Description                                                           |
| ----------------- | --------- | --------------------------------------------------------------------- |
| *Pulse Input* (►) | **Pulse** | A standard input **Pulse**, to trigger the execution of the **Node**. |
| `Input`           | **Float** | The number whose logarithm you wish to calculate.                     |

## Outputs

| Output             | Type      | Description                                                                                                                            |
| ------------------ | --------- | -------------------------------------------------------------------------------------------------------------------------------------- |
| *Pulse Output* (►) | **Pulse** | A standard output **Pulse**, to move onto the next **Node** along the **Logic Branch**, once this **Node** has finished its execution. |
| `Exponent`         | **Float** | The *logarithm* of `Input` in the chosen *base*.                                                                                       |

## External Links

* [*Logarithmic Functions*](https://www.sparknotes.com/math/precalc/exponentialandlogarithmicfunctions/section2/) on sparknotes.