No way to copy a tensor from gpu to cpu to pre allocated array.

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
machine-learning

Research direction

Start by tracing the tensor transfer path used by gpuResult.cpu() and cpuResult.data().ToArray(), then inspect the existing host-copy APIs. Done means a GPU result can be copied into a caller-provided preallocated float array without allocating a new array, with coverage for the supported copy behavior.

Written by the indexing model from the issue text.

Description

Doesnt appear to be any way to transfer a result tensor in to an existing cpu float array. Below requires new memory allocation.

    var cpuResult = gpuResult.cpu();
    float[] result = cpuResult.data<float>().ToArray();

If this is part of a loop, this is a lot of wasted memory allocation and time! Below is how libraries normally do things. eg. CUDA.

float[] cpuResult ..... (pre allocated further up)
gpuResult.CopyToHost(cpuResult);

Maybe I missed this CopyTo because its kinda essential for any gpu type library (?!)

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