phanerozoic/threshold-parity4
017
threshold-parity4
4-bit parity function. Outputs 1 if odd number of inputs are high.
Function
parity4(a, b, c, d) = a XOR b XOR c XOR d
Architecture
Tree structure: parity(a,b,c,d) = XOR(XOR(a,b), XOR(c,d))
Three XOR2 gates, each using OR-NAND-AND structure:
- xorab: XOR(a, b) - parallel with xorcd
- xorcd: XOR(c, d) - parallel with xorab
- xorfinal: XOR(xorab, xor_cd)
Layer structure:
- or1, nand1 (a,b) and or2, nand2 (c,d) in parallel
- and1 (xorab) and and2 (xorcd)
- or3, nand3 (on xor outputs)
- and3 (final output)
Parameters
Usage
from safetensors.torch import load_file
w = load_file('model.safetensors')
def xor2(a, b, prefix):
or_out = int(a * w[f'{prefix}.or.weight'][0] + b * w[f'{prefix}.or.weight'][1] + w[f'{prefix}.or.bias'] >= 0)
nand_out = int(a * w[f'{prefix}.nand.weight'][0] + b * w[f'{prefix}.nand.weight'][1] + w[f'{prefix}.nand.bias'] >= 0)
return int(or_out * w[f'{prefix}.and.weight'][0] + nand_out * w[f'{prefix}.and.weight'][1] + w[f'{prefix}.and.bias'] >= 0)
def parity4(a, b, c, d):
return xor2(xor2(a, b, 'xor_ab'), xor2(c, d, 'xor_cd'), 'xor_final')
print(parity4(1, 0, 1, 0)) # 0 (even)
print(parity4(1, 1, 1, 0)) # 1 (odd)License
MIT
