---
title: "ClikaRT::ops::nansum"
sidebar_label: "nansum"
description: "Sum over dims, treating NaN entries as missing (contributing zero). Float dtypes only carry NaN; for integer inputs this is plain sum. input the input tensor. dims axes to reduce; empty = all axes."
---

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

## nansum() {#nansum}

<div class="api-signature">

[`Tensor`](../Tensor.md) **`nansum`**(<br />
&nbsp;&nbsp;&nbsp;&nbsp;[`Tensor`](../Tensor.md) `input`,<br />
&nbsp;&nbsp;&nbsp;&nbsp;[`ClikaRT::Span`](../Span.md)`<const std::int64_t>` `dims` `=` `{}`,<br />
&nbsp;&nbsp;&nbsp;&nbsp;`bool` `keepdim` `=` `false`<br />
)

</div>

Sum over `dims`, treating NaN entries as missing (contributing zero).

Float dtypes only carry NaN; for integer inputs this is plain [`sum`](./sum.md#sum).

**Parameters**

- `input`: the input tensor.
- `dims`: axes to reduce; empty = all axes.
- `keepdim`: keep reduced axes as size-1 dims; default false.

**Returns:** the NaN-skipping sum; shape = `input` minus `dims`; dtype = `input`'s.

**Throws**

- `ClikaRT::Error`: (`INVALID_ARGUMENT`) on an out-of-range `dims` entry.

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Declared in `ClikaRT/compute/ops.h`, line 4437

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