---
title: "ClikaRT::ops::hash_64"
sidebar_label: "hash_64"
description: "64-bit content hash of input's packed bytes (row-major logical order; strided inputs are materialized internally)."
---

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

## hash\_64() {#hash_64}

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[`Tensor`](../Tensor.md) **`hash_64`**([`Tensor`](../Tensor.md) `input`, `std::uint64_t` `seed` `=` `0`)

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64-bit content hash of `input`'s packed bytes (row-major logical order; strided inputs are materialized internally). A frozen function of (seed, bytes): identical on every platform, backend, and ISA tier, so digests are safe to persist and compare across devices. `seed` perturbs the key; 0 selects the runtime's fixed content-addressing key.

**Returns:** a 0-D UInt64 digest.

**Throws**

- `ClikaRT::Error`: when the input's dtype is not served for this operation (the machine-readable reason rides `code_name()`).

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Declared in `ClikaRT/compute/ops.h`, line 4480

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