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AI engineers claim new algorithm reduces AI power consumption by 95%

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Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#2
Isn't this just taking advantage of "log(x) + log(y) = log(xy)"? The IEEE754 floating-point representation stores floats as sign, mantissa, and exponent -- ignore the first two (you quantitized anyway, right?), and the exponent is just an integer storing log() of the float.

Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#4
post #2

Isn't this just taking advantage of "log(x) + log(y) = log(xy)"? The IEEE754 floating-point representation stores floats as sign, mantissa, and exponent -- ignore the first two (you quantitized anyway, right?), and the exponent is just an integer storing log() of the float.

yes. and the next question is 'ok, how do we add'

Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#6
post #2

Isn't this just taking advantage of "log(x) + log(y) = log(xy)"? The IEEE754 floating-point representation stores floats as sign, mantissa, and exponent -- ignore the first two (you quantitized anyway, right?), and the exponent is just an integer storing log() of the float.

yes. and the next question is 'ok, how do we add'

I guess that if the bulk of the computation goes into the multiplications, you can work in the log-space and simply sum, and when the time comes to actually do a sum on the original space you can go back and sum.

Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#7
https://arxiv.org/abs/2410.00907

ABSTRACT

Large neural networks spend most computation on floating point tensor multiplications. In this work, we find that a floating point multiplier can be approximated by one integer adder with high precision. We propose the linear-complexity multiplication (L-Mul) algorithm that approximates floating point number multiplication with integer addition operations. The new algorithm costs significantly less computation resource than 8-bit floating point multiplication but achieves higher precision. Compared to 8-bit floating point multiplications, the proposed method achieves higher precision but consumes significantly less bit-level computation. Since multiplying floating point numbers requires substantially higher energy compared to integer addition operations, applying the L-Mul operation in tensor processing hardware can potentially reduce 95% energy cost by elementwise floating point tensor multiplications and 80% energy cost of dot products. We calculated the theoretical error expectation of L-Mul, and evaluated the algorithm on a wide range of textual, visual, and symbolic tasks, including natural language understanding, structural reasoning, mathematics, and commonsense question answering. Our numerical analysis experiments agree with the theoretical error estimation, which indicates that L-Mul with 4-bit mantissa achieves comparable precision as float8 e4m3 multiplications, and L-Mul with 3-bit mantissa outperforms float8 e5m2. Evaluation results on popular benchmarks show that directly applying L-Mul to the attention mechanism is almost lossless. We further show that replacing all floating point multiplications with 3-bit mantissa L-Mul in a transformer model achieves equivalent precision as using float8 e4m3 as accumulation precision in both fine-tuning and inference.

Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#8
post #2

Isn't this just taking advantage of "log(x) + log(y) = log(xy)"? The IEEE754 floating-point representation stores floats as sign, mantissa, and exponent -- ignore the first two (you quantitized anyway, right?), and the exponent is just an integer storing log() of the float.

yes. and the next question is 'ok, how do we add'

Yes. I haven't yet read this paper to see what exactly it says is new, but I've definitely seen log-based representations under development before now. (More log-based than the regular floating-point exponent, that is. I don't actually know the argument behind the exponent-and-mantissa form that's been pretty much universal even before IEEE754, other than that it mimics decimal scientific notation.)

Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#9
I posted this about a week ago:

https://news.ycombinator.com/item?id=41816598

This has been done for decades in digital circuits, FPGA’s, Digital Signal Processing, etc. Floating point is both resource and power intensive and using FP without the use of dedicated FP processing hardware is something that has been avoided and done without for decades unless absolutely necessary.

Re: AI engineers claim new algorithm reduces AI power consumption by 95%

#10
Extraordinary claims require extraordinary evidence. Maybe it's possible, but consider that some really smart people, in many different groups, have been working diligently in this space for quite a while; so claims of 95% savings on energy costs _with equivalent performance_ is in the extraordinary category. Of course, we'll see when the tide goes out.
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