Montek Singh
COMP790-084
Oct 4, 2011
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Basics of probabilistic design
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energy-correctness tradeoff
probabilistic Boolean logic
approximate arithmetic
applications
Next class:
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architectures and design tools
case studies
challenges and benefits
open questions
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Operate at reduced voltage
◦ more noise but lesser energy consumption
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Where is this acceptable?
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Where could this be even desirable?
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Logic values have associated probabilities
◦ p: probability that the value is correct
 introduces non-determinism
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Thermal noise makes any switch noisy
◦ probability of error depends on thermal noise vs.
operating voltage
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Thermal noise makes any switch noisy
◦ probability of error depends on thermal noise vs.
operating voltage
 higher supply voltage (Vdd) w.r.t. noise (sigma) implies
higher probability of correct logic
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Everything else remaining fixed:
◦ energy required goes up exponentially with prob. of
correctness
◦ energy required goes up quadratically with noise
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energy required goes
up exponentially with
prob. of correctness
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Probabilistic Cellular Automata
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Random Neural Networks
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Hyper Encryption
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Bayesian Inference