658 reputation
416
bio website darwinbots.com
location
age
visits member for 3 years, 10 months
seen 5 hours ago

I'm a programmer in the video game industry, working with physics engines. In my spare time, I'm working on an engine for a physically simulated artificial life simulator (Darwinbots). My mathematical interests primarily stem from that, and delve in to linear algebra and numerical analysis.


Dec
24
accepted How many orthogonal matrices map one vector to another?
Dec
14
awarded  Nice Question
Dec
8
comment How many orthogonal matrices map one vector to another?
Ah, simple once I see it :) Thanks!
Dec
8
asked How many orthogonal matrices map one vector to another?
Dec
5
asked Decomposing a Householder transformation?
Oct
9
asked $C^{\infty}$ distance function for polygons?
Oct
7
awarded  Revival
Oct
1
answered Calculators using Taylor polynomials?
Sep
24
awarded  Autobiographer
Sep
23
asked Rotations and inequalities
Sep
19
comment LQ decomposition and inequalities
Ah, interesting :) And very frustrating for what I'm doing, but oh well.
Sep
19
accepted LQ decomposition and inequalities
Sep
19
awarded  Yearling
Sep
19
asked LQ decomposition and inequalities
Sep
9
awarded  Popular Question
Aug
29
comment Reentrant constraints in active set algorithm?
I know, just pointing out the convexity can matter.
Aug
29
comment Reentrant constraints in active set algorithm?
In the case of PD Q, there is an algorithm for polynomial running time. See en.wikipedia.org/wiki/Quadratic_programming#Complexity. Not to say the point you're making is wrong. PSD is not PD. Just FYI.
Aug
28
comment Reentrant constraints in active set algorithm?
Thanks for the note about the Newton direction, but it's actually the same as the gradient in the problem I'm solving (more like lsqlin from Matlab mathworks.com/help/optim/ug/lsqlin.html). Unless I messed up the math. I figured phrasing it in terms of quadratic programming would garner more responses. ------ In general, for non convex programs, I think you can get reentrant constraints (the random small matrices you're mentioning), but I think the PSD constraint on Q prevents those. Still, I'll play with it and see if I can prove myself wrong.
Aug
28
revised Reentrant constraints in active set algorithm?
fixing inequality
Aug
28
comment Reentrant constraints in active set algorithm?
oh yep, I wanted against b instead of 0, thanks.