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Emerging Technologies of Computation
Montek Singh
COMP790-084Oct 6, 2011
Today’s topics:◦ approximate arithmetic◦ simple applications
Next time:◦ more applications◦ architectures and design tools◦ challenges and benefits◦ open questions
Today: Probabilistic Design
Supply reduced voltage to adder gates◦ fine-grain: each stage receives own voltage◦ coarse-grain: use binning
Probabilistic arithmetic
Error induced:
Energy consumed:
Probabilistic arithmetic
Voltage selection
◦ fine-grain: each stage receives own voltage
◦ coarse-grain: use binning
Probabilistic arithmetic
Geometric model for voltage assignment◦ higher order bit receives progressively higher
voltage
Probabilistic arithmetic
Energy-correctness tradeoff
Probabilistic arithmetic
Energy-correctness tradeoff example
Probabilistic arithmetic
Lower voltage causes clock deadline to be missed◦ some of the longer carry chains cannot complete!
Delay-Induced Approximation
Delay-Induced Approximation
Example: DFT
Delay-Induced Approximation
Example: DFT
Delay-Induced Approximation