docs-v2/content/flux/v0/stdlib/internal/promql/linearregression.md

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---
title: promql.linearRegression() function
description: >
`promql.linearRegression()` implements linear regression functionality required to implement
PromQL's [`deriv()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#deriv)
and [`predict_linear()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#predict_linear) functions.
menu:
flux_v0_ref:
name: promql.linearRegression
parent: internal/promql
identifier: internal/promql/linearRegression
weight: 201
---
<!------------------------------------------------------------------------------
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`promql.linearRegression()` implements linear regression functionality required to implement
PromQL's [`deriv()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#deriv)
and [`predict_linear()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#predict_linear) functions.
**Important**: The `internal/promql` package is not meant for external use.
##### Function type signature
```js
(
<-tables: stream[{A with _value: float, _time: time, _stop: time}],
?fromNow: float,
?predict: bool,
) => stream[{B with _value: float}]
```
{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}
## Parameters
### tables
Input data. Default is piped-forward data (`<-`).
### predict
Output should contain a prediction.
### fromNow
Time as a floating point value.