---
title: "ClikaRT::ops::l1_loss"
sidebar_label: "l1_loss"
description: "Mean-absolute-error loss between input and target. \\[ \\ell_i = |x_i - y_i| \\] input predictions; float dtype. target ground truth; same shape as input. reduction None / Mean / Sum; default Mean."
---

<!-- Generated by tools/doxygen2mdx from Doxygen XML. Do not edit. -->

<span class="api-kind api-kind--function">function</span>

## l1\_loss() {#l1_loss}

<div class="api-signature">

[`Tensor`](../Tensor.md) **`l1_loss`**(<br />
&nbsp;&nbsp;&nbsp;&nbsp;[`Tensor`](../Tensor.md) `input`,<br />
&nbsp;&nbsp;&nbsp;&nbsp;[`Tensor`](../Tensor.md) `target`,<br />
&nbsp;&nbsp;&nbsp;&nbsp;[`Reduction`](./index.md#Reduction) `reduction` `=` [`Reduction::Mean`](./index.md#Reduction)<br />
)

</div>

Mean-absolute-error loss between `input` and `target`.

$$
\ell_i = |x_i - y_i|
$$

**Parameters**

- `input`: predictions; float dtype.
- `target`: ground truth; same shape as `input`.
- `reduction`: `None` / `Mean` / `Sum`; default `Mean`.

**Returns:** the loss (0-D under `Mean`/`Sum`).

**Throws**

- `ClikaRT::Error`: (`INVALID_ARGUMENT`) on an input/target shape mismatch.

<div class="api-declared">

Declared in `ClikaRT/compute/ops.h`, line 3071

</div>