Alec Jacobson

Associate Professor, Computer Science, University of Toronto; Adobe Research Toronto

[Alec Jacobson @_AlecJacobson]

📢 libigl v2.5 released
🐍 pip install libigl
Eigen → 3.4
CGAL → 5.6
OpenGL → 4.1
CGAL and its dependencies (GMP+MPFR) compile everywhere from source via cmake
Github actions finish faster and rarely fail due to heap size
Shadow mapping in viewer
…

[Alec Jacobson @_AlecJacobson]

✌️ not going to be on this site much anymore. See you somewhere else.

[Alec Jacobson @_AlecJacobson]

@rms80 Hold em hostage. Only fix it if they hire you back for $10M an hour. Surely no one else can find let along fix this bug. You have all the leverage. Don't settle for less. #geometryguru #unreal #unrealstoreloadingscreenisryansfault

[Alec Jacobson @_AlecJacobson]

🖖

#include <autodiff/reverse/var.hpp>

template <typename T> T f(T & x)
{
// "clever" branch to avoid 0/0 at x=0
if(x == 0.0) return 1.0;
return sin(x)/x + x*(x-1.0);
}

[Alec Jacobson @_AlecJacobson]

You can do this so your long titles don't look as terrible:

\newcommand{\abbrtitle}{Clever Short Title}
\title[\abbrtitle]{\abbrtitle:\\
Long Part Causing Line Breaks in Title and Spills in Headers}

[Alec Jacobson @_AlecJacobson]

@mnewberg @rms80 I knew it.

[Jesse Thomason @_jessethomason_]

Trying out a Role-Playing Paper-Reading Seminar in the style of @colinraffel's blog https://t.co/8Pht0icxfO in my History of Language and Computing graduate course this semester. Eager to see how it plays out, but I wanted to show off the class materials that just arrived :)

[Alec Jacobson @_AlecJacobson]

@_jessethomason_ @colinraffel amazing. I love this.

[Alec Jacobson @_AlecJacobson]

@Arxiv_Daily nah

[Alec Jacobson @_AlecJacobson]

Q: We're almost out of time. Do you have any questions for me?
A: Yes, how do you represent a mesh with a slit along a single edge?

[Alec Jacobson @_AlecJacobson]

you may also like libigl 🤝 TinyAD https://t.co/YkGOp49UkD

[Alec Jacobson @_AlecJacobson]

Typical. More time wrangling cmake than writing C++.

Here's an example project using both libigl and https://t.co/ANWRw9oVuB (a nice C++ library for forward and reverse automatic differentiation).

https://t.co/wWifgtrGgb

[Alec Jacobson @_AlecJacobson]

@tzumaoli Heh. I was just reading this this morning.

[Alec Jacobson @_AlecJacobson]

Mathematically is there any reason to think that:

f(x) = x

is different from

g(x) = / 0 if x=0
\ x if x≠ 0

?

[Alec Jacobson @_AlecJacobson]

This kind of example pops up as a pitfall in autodiff discussions. And in a recent discussion regarding symbolic differentiation, somebody appeared to argue that f and g are different in some essentially way which excuses the symdiff library from finding equivalent derivatives.

[Alec Jacobson @_AlecJacobson]

I would think of the piecewise definition as an _implementation_ of the same function as f. Thus they're the same and consequently have the same derivative ∂f/∂x = ∂g/∂x, even at x=0.

[Alec Jacobson @_AlecJacobson]

I no longer have to send Wayback Machine links to my own blog articles!

Successfully transferred my wordpress blog from bluehost to my static academic page. Old post urls should redirect correctly.
https://t.co/sGjDASacFq

[Alec Jacobson @_AlecJacobson]

@benhouston3d I didn't try out any higher-order ones yet, but I'm bothered by the fact that the simplest case already has non-trivial error

0---1
| |
1----?

? should be √2 but FMM predicts 1+√½

Fitting a quadratic to this case would get it right. Not sure how that generalizes

[Alec Jacobson @_AlecJacobson]

Playing with the fast marching method for the first time.

[Alec Jacobson @_AlecJacobson]

been doing this for a while and I'm still not sure I know whether "strongly" or "enthusiastically" is better.