---
title: "ClikaRT::nn::NLLLoss"
sidebar_label: "NLLLoss"
description: "Negative log-likelihood over log-probabilities with the class axis last."
---

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**Header:** `ClikaRT/nn/generated/loss.h`  
**Inherits:** [`ClikaRT::nn::Module`](./Module.md)

Negative log-likelihood over log-probabilities with the class axis last. The module form of [`ClikaRT::ops::nll_loss`](../ops/nll_loss.md#nll_loss), which documents the full contract (shapes, dtypes, errors); construct once, then call it like a function.

## Member functions

### NLLLoss() {#NLLLoss}

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`explicit` **`NLLLoss`**([`NLLLossOptions`](./NLLLossOptions.md) `options` `=` `{}`)

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Constructs the module from [`options`](./NLLLoss.md#options) (every default when omitted).

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Declared in `ClikaRT/nn/generated/loss.h`, line 336

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### forward() {#forward}

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[`Tensor`](../Tensor.md) **`forward`**([`Tensor`](../Tensor.md) `input`, [`Tensor`](../Tensor.md) `target`) `const`

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[`forward_impl`](./NLLLoss.md#forward), unwrapped: raises [`ClikaRT::Error`](../Error.md) on failure.

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Declared in `ClikaRT/nn/generated/loss.h`, line 349

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### operator()() {#operator-call}

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[`Tensor`](../Tensor.md) **`operator()`**([`Tensor`](../Tensor.md) `input`, [`Tensor`](../Tensor.md) `target`) `const`

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Same as [`forward`](./NLLLoss.md#forward).

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Declared in `ClikaRT/nn/generated/loss.h`, line 353

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### options() {#options}

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`const` [`NLLLossOptions`](./NLLLossOptions.md)`&` **`options`**() `const`

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The settings this module was constructed with.

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Declared in `ClikaRT/nn/generated/loss.h`, line 357

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