Laurent Lessard

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Laurent Lessard

Laurent Lessard

@LaurentLessard

Associate Professor of MIE @Northeastern. Interested in control theory, optimization, math, and puzzles. The glass is twice as large as it needs to be.

Boston, MA Katılım Nisan 2009
341 Takip Edilen1.2K Takipçiler
Laurent Lessard
Laurent Lessard@LaurentLessard·
"Deadlines are final and no extensions will be given" You got me @IEEECDC2025 --- I totally fell for it! Happy April Fools everybody!
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Krishnamurthy (Dj) Dvijotham
Can your AI keep up with dynamic attackers? In a paper to appear at #AISTATS2025 with @avibose22 @LaurentLessard and Maryam Fazel, we study robustness to learning algorithms to dynamic data poisoning attacks that can adapt attacks while observing the progress of learning
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Laurent Lessard
Laurent Lessard@LaurentLessard·
@gravity_levity It doesn't decay quite that quickly, but it's still fast: P(1) ~ 1/k! So basically: -log(P(1)) = O(k*log(k)) rather than: -log(P(1)) = O(k^2), which is what you had conjectured.
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Brian Skinner
Brian Skinner@gravity_levity·
@LaurentLessard How does the probability decay with starting location k? Is it Gaussian at large k, P(1) ~ exp(-const.*k^2) ?
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Laurent Lessard
Laurent Lessard@LaurentLessard·
This week's #Fiddler puzzle is a random walk: From (k), you hop to (k-1) with probability 1/k and hop to (k+1) otherwise. If you start at (2), what is the probability you eventually hop to (1)? I wrote a short tutorial here: laurentlessard.com/bookproofs/can…
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Laurent Lessard
Laurent Lessard@LaurentLessard·
Update: after 2 hours and 35 minutes on the tarmac, we are finally deplaning.
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Laurent Lessard
Laurent Lessard@LaurentLessard·
The pilot keeps saying there is "nothing he can do". You mean to tell me there are no other gates available at the airport? We can't deplane on the tarmac? This is a full flight with 8 seats across and we've been on this plane for almost 10 hours now.
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Laurent Lessard
Laurent Lessard@LaurentLessard·
Hey @AerLingus I'm on a flight from Dublin to Boston and we've been stuck on the tarmac at @loganairports after landing for TWO HOURS (and counting). Apparently other planes are being de-iced which is preventing us from deplaning...
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Laurent Lessard
Laurent Lessard@LaurentLessard·
Halloween #fiddler puzzle: A bag contains N Reese's cups and an unknown number of candy corn pieces. You reach into the bag k ≤ n times at random and pull out a Reese's each time! How many candy corn do you expect to be in the bag? @xaqwg My write-up: laurentlessard.com/bookproofs/hal…
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Lars Lindemann
Lars Lindemann@LarsLindemann2·
Great pleasure of hosting @LaurentLessard at USC who spoke about "An automatic system to detect equivalence between iterative algorithms" 🙂
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Laurent Lessard
Laurent Lessard@LaurentLessard·
@SpottedGeck @xaqwg Nice! You can approximate further using: Φ(x)-Φ(-x) ≈ 2x*Φ'(0) and you get: p(n) ≈ √6 / √(πn)
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SpottedGeck
SpottedGeck@SpottedGeck·
@xaqwg #scrollTo=0EcCHWcxdQXE" target="_blank" rel="nofollow noopener">colab.research.google.com/drive/1BWzQ0NH…
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Tom Keith
Tom Keith@tom_keith1·
#ThisWeeksFiddler by @xaqwg asks, how likely is it that n numbers rounded first and then summed equals the same numbers summed first and then rounded?
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Laurent Lessard
Laurent Lessard@LaurentLessard·
Thanks for reading! Let us know if you have any comments/questions!
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Laurent Lessard
Laurent Lessard@LaurentLessard·
One such example (we discuss others in the paper) is quasi-Newton methods. For these methods, line search serves the purpose of guaranteeing global convergence rather than finding a "best" step size. Once we enter a local convergence regime, adjustments are no longer beneficial.
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Laurent Lessard
Laurent Lessard@LaurentLessard·
New preprint with Joao Cavalcanti and @Ashia__Wilson! arxiv.org/abs/2408.13150 tl;dr: If you make your backtracking line search routine ADAPTIVE, you get faster continuous optimization algorithms with no additional computational burden! Longer summary below!🧵
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