| | ---
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| | license: mit
|
| | tags:
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| | - pytorch
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| | - safetensors
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| | - threshold-logic
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| | - neuromorphic
|
| | ---
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| |
|
| | # threshold-signbit8
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| |
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| | Extract sign bit (MSB) of 8-bit number.
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| |
|
| | ## Function
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| |
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| | signbit8(a7..a0) = a7
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| |
|
| | In 2's complement representation:
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| | - Output 0: non-negative (0 to 127)
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| | - Output 1: negative (-128 to -1)
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| |
|
| | ## Truth Table (selected)
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| |
|
| | | unsigned | signed | signbit |
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| | |---------:|-------:|:-------:|
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| | | 0 | 0 | 0 |
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| | | 127 | +127 | 0 |
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| | | 128 | -128 | 1 |
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| | | 255 | -1 | 1 |
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| |
|
| | ## Architecture
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| |
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| | Single neuron extracting MSB:
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| |
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| | - Weights: [1, 0, 0, 0, 0, 0, 0, 0]
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| | - Bias: -1
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| |
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| | Fires when: a7 - 1 >= 0, i.e., a7 >= 1
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| |
|
| | ## Parameters
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| |
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| | | | |
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| | |---|---|
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| | | Inputs | 8 |
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| | | Outputs | 1 |
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| | | Neurons | 1 |
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| | | Layers | 1 |
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| | | Parameters | 9 |
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| | | Magnitude | 2 |
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| |
|
| | ## Usage
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| |
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| | ```python
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| | from safetensors.torch import load_file
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| | import torch
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| |
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| | w = load_file('model.safetensors')
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| |
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| | def signbit8(a7, a6, a5, a4, a3, a2, a1, a0):
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| | inp = torch.tensor([float(a7), float(a6), float(a5), float(a4),
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| | float(a3), float(a2), float(a1), float(a0)])
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| | return int((inp @ w['neuron.weight'].T + w['neuron.bias'] >= 0).item())
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| |
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| | print(signbit8(0, 1, 1, 1, 1, 1, 1, 1)) # 0 (value = +127)
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| | print(signbit8(1, 0, 0, 0, 0, 0, 0, 0)) # 1 (value = -128)
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| | ```
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| |
|
| | ## License
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| |
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| | MIT
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| |
|
