squiggle/packages/website/docs/Api/Distribution.md

---
sidebar_position: 2
title: Distribution
---

## Main

### mixture

```javascript
(...distributionLike, weights:list<float>):distribution
```

**Examples**

```javascript
mixture(normal(5, 1), normal(10, 1));
```

### sample

Get one random sample from the distribution

```javascript
(distribution):number
```

**Examples**

```javascript
sample(normal(5, 2));
```

### sampleN

Get n random samples from the distribution

```javascript
(distribution, number):list<number>
```

**Examples**

```javascript
sample(normal(5, 2), 100);
```

### mean

Get the distribution mean

```javascript
(distribution):number
```

**Examples**

```javascript
mean(normal(5, 2));
```

### stdev

```javascript
(distribution):number
```

### variance

```javascript
(distribution):number
```

### mode

```javascript
(distribution):number
```

### cdf

```javascript
(distribution, number):number
```

**Examples**

```javascript
cdf(normal(5, 2), 3);
```

### pdf

```javascript
(distribution, number):number
```

**Examples**

```javascript
pdf(normal(5, 2), 3);
```

### pmf

```javascript
(distribution, number):number
```

**Examples**

```javascript
pmf(bernoulli(0.3), 0); // 0.7
```

### inv

```javascript
(distribution, number):number
```

**Examples**

```javascript
inv(normal(5, 2), 0.5);
```

### toPointSet

Converts a distribution to the pointSet format

```javascript
(distribution):pointSetDistribution
```

**Examples**

```javascript
toPointSet(normal(5, 2));
```

### toSampleSet

Converts a distribution to the sampleSet format, with n samples

```javascript
(distribution,n):sampleSetribution
```

**Examples**

```javascript
toSampleSet(normal(5, 2));
```

### truncateLeft

Truncates the left side of a distribution. Returns either a pointSet distribution or a symbolic distribution.

```javascript
(distribution, l:number, {normalize: boolean=true}):distribution
```

**Examples**

```javascript
truncateLeft(normal(5, 2), 3);
```

### truncateRight

Truncates the right side of a distribution. Returns either a pointSet distribution or a symbolic distribution.

```javascript
(distribution, r:number, {normalize: boolean=true}):distribution
```

**Examples**

```javascript
truncateLeft(normal(5, 2), 6);
```

### klDivergence

Kullback–Leibler divergence between two distributions

```javascript
(distribution, distribution):number
```

**Examples**

```javascript
klDivergence(normal(5, 2), normal(5, 4)); // returns 0.57
```

### logScore

```javascript
({estimate: distribution, prior?: distribution, answer: distribution|number}):number
```

**Examples**

```javascript
logScore({ estimate: normal(5, 2), prior: normal(5.5, 4), answer: 2.3 });
```

### toString

```javascript
(distribution):string
```

**Examples**

```javascript
toString(normal(5, 2));
```

### toSparkline

Produce a sparkline of length n

```javascript
(distribution, n=20):string
```

**Examples**

```javascript
toSparkline(normal(5, 2), 10);
```

### inspect

Prints the value of the distribution to the Javascript console, then returns the distribution.

```javascript
(distribution):distribution
```

**Examples**

```javascript
inspect(normal(5, 2));
```

### normalize

Normalize a distribution. This means scaling it appropriately so that it's cumulative sum is equal to 1.

```javascript
(distribution):distribution
```

**Examples**

```javascript
normalize(normal(5, 2));
```

### isNormalized

Check of a distribution is normalized. Most distributions are typically normalized, but there are some commands that could produce non-normalized distributions.

```javascript
(distribution):bool
```

**Examples**

```javascript
isNormalized(normal(5, 2)); // returns true
```

### integralSum

Get the sum of the integral of a distribution. If the distribution is normalized, this will be 1.

```javascript
(distribution):number
```

**Examples**

```javascript
integralSum(normal(5, 2));
```

### add

```javascript
(distributionLike, distributionLike): distribution
```

### sum

```javascript
(list<distributionLike>): distribution
```

### multiply

```javascript
(distributionLike, distributionLike): distribution
```

### product

```javascript
(list<distributionLike>): distribution
```

### subtract

```javascript
(distributionLike, distributionLike): distribution
```

### divide

```javascript
(distributionLike, distributionLike): distribution
```

### pow

```javascript
(distributionLike, distributionLike): distribution
```

### exp

```javascript
(distributionLike, distributionLike): distribution
```

### log

```javascript
(distributionLike, distributionLike): distribution
```

### log10

```javascript
(distributionLike, distributionLike):distribution
```

### unaryMinus

```javascript
(distribution):distribution
```

### dotAdd

```javascript
(distributionLike, distributionLike): distribution
```

### dotSum

```javascript
(list<distributionLike>): distribution
```

### dotMultiply

```javascript
(distributionLike, distributionLike): distribution
```

### dotProduct

```javascript
(list<distributionLike>): distribution
```

### dotSubtract

```javascript
(distributionLike, distributionLike): distribution
```

### dotDivide

```javascript
(distributionLike, distributionLike): distribution
```

### dotPow

```javascript
(distributionLike, distributionLike): distribution
```

### dotExp

```javascript
(distributionLike, distributionLike): distribution
```

### scaleMultiply

```javascript
(distributionLike, distributionLike): distribution
```

### scalePow

```javascript
(distributionLike, distributionLike): distribution
```

### scaleExp

```javascript
(distributionLike, distributionLike): distribution
```

### scaleLog

```javascript
(distributionLike, distributionLike): distribution
```

### scaleLog10

```javascript
(distributionLike, distributionLike): distribution
```

### scaleLogWithThreshold

```javascript
(distributionLike, distributionLike, number): distribution
```