Module backend 

Backend abstractions for CPU and GPU execution.

This module defines the Backend trait and implementations:

• Cpu: CPU backend with SIMD acceleration
• Cuda: CUDA backend (optional, requires cuda feature)

Structs

Cpu

CPU backend using Vec storage.

Traits

Backend

Backend trait for tensor execution.

BackendScalar

Marker trait for scalar types supported by a specific backend.

Storage

Storage trait for tensor data.