1,326 reputation
618
bio website yaroslavvb.blogspot.com
location Mountain View, CA
age 33
visits member for 3 years, 8 months
seen Apr 15 at 17:49

Software Engineer at Google (StreetView/OCR)

Google+ profile


Mar
2
comment Turning SDP into vectorized form
I don't understand, $\mathbf{x}$ is unknown while $G_1$ should be fixed ahead of time
Mar
2
revised Turning SDP into vectorized form
added 76 characters in body
Mar
2
asked Turning SDP into vectorized form
Feb
26
revised On the existence of closed form solutions to finite combinatorial problems
deleted 2 characters in body
Feb
25
revised On the existence of closed form solutions to finite combinatorial problems
deleted 29 characters in body
Feb
25
answered On the existence of closed form solutions to finite combinatorial problems
Feb
20
revised How to solve transcendental equations with Mathematica 7?
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Feb
20
answered How to solve transcendental equations with Mathematica 7?
Feb
18
comment Higher dimensional analog to planar graphs?
When you say "triangulation", do you mean representing vertices of a graph as points in the space? I have trouble imagining how tree structured-graphs fit into this construction
Feb
18
comment Higher dimensional analog to planar graphs?
Intuitively it seems that such "cell" construction would have bounded doubling dimensions, whereas planar graphs can have unbounded doubling dimension
Feb
18
answered Higher dimensional analog to planar graphs?
Feb
18
accepted spanning trees as graph homomorphisms
Feb
17
comment spanning trees as graph homomorphisms
OK, makes sense (although using G instead of H in second paragraph confused me at first). The reason its interesting is because of the theorem (from linked blog post) that $G_1,G_2$ are isomorphic iff $|\text{Hom}(G_1,H)|=|\text{Hom}(G_2,H)|$, so now it seems that "number of spanning trees" doesn't give any information about the graph that's not captured by "homomorphism definable" invariants like number of independent sets or proper colorings
Feb
16
comment spanning trees as graph homomorphisms
I'm interested in representing "number of spanning trees" as number of certain homomorphisms, not sure your comment rules it out. This post gives the motivation for counting graph homomorphisms -- rjlipton.wordpress.com/2011/02/14/…
Feb
16
asked spanning trees as graph homomorphisms
Feb
3
comment Best way to exactly solve a linear system (300x300) with integer coefficients
That seems to be the case. They may be using a proprietary method which doesn't have a common name. OneStepRow reduction however isn't that bad, about 20 seconds on my laptop for 200x200 matrix with entries in billions and 80% zeros
Feb
3
comment Best way to exactly solve a linear system (300x300) with integer coefficients
Out of those ones, "OneStepRowReduction" is the fastest. For 300x300 matrix with -2 billion..2 billion entries, Method->Automatic takes about 2 seconds, "OneStepRowReduction" not sure, but more than a minute. Takes about 6 seconds on 150x150 matrix with such entries, whereas Automatic takes 0.2 seconds
Feb
3
comment Best way to exactly solve a linear system (300x300) with integer coefficients
yes, here's the output I got from the code above -- pastebin.com/YY5pptcD
Feb
3
revised Best way to exactly solve a linear system (300x300) with integer coefficients
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Feb
3
answered Best way to exactly solve a linear system (300x300) with integer coefficients