Per Alexandersson

less info
753 reputation
313
bio website www2.math.su.se/~per
location Zurich, Switzerland
age 27
visits member for 2 years, 6 months
seen yesterday

Currently interested in Schur functions and semistandard Young tableaux and misc. related representation theory and combinatorics.

Phd thesis defended 2013, titled Combinatorial Methods in Complex Analysis.

I keep an eye out for interesting results related to complex dynamics, computability, and computer-assisted research. I use Mathematica extensively in my research. My other main programming languages are Java, LaTeX, PHP, C, etc.


Mar
5
comment Generating Gelfand-Tsetlin patterns
@belisarius cf = Flatten[stuff,1] can be optimized to cf = Join@@(stuff).
Mar
5
comment Generating Gelfand-Tsetlin patterns
@IstvánZachar Are there any performance issues with Return? I read that it is a bit quirky, and is more "procedural" than "functional", so is it something to avoid in general?
Mar
5
comment Generating Gelfand-Tsetlin patterns
@IstvánZachar Oh, ok, is there a particular reason why one wish to avoid return? I am probalby just used to Java, so it feels easier to read in this manner.
Mar
5
revised Generating Gelfand-Tsetlin patterns
added extra check in findPaths
Mar
5
comment Generating Gelfand-Tsetlin patterns
Wow, this is very efficient! How does the algorithm work? I took the liberty of adding an extra check in findPaths; looks like some corner cases mess up your code otherwise.
Mar
5
suggested suggested edit on Generating Gelfand-Tsetlin patterns
Mar
5
awarded  Nice Question
Mar
1
comment Dot shading a.k.a. Stippling effect
Ah, cool! I had some feeling I might have seen it somewhere, so yes, it is perhaps best to close this. Thanks!
Mar
1
asked Dot shading a.k.a. Stippling effect
Feb
25
comment Generating Gelfand-Tsetlin patterns
I have some other functionality that I have coded that does not exist in Sage. Besides, I am not sure, but I don't think Sage supports skew patterns, only "regular" ones.
Feb
24
awarded  Promoter
Feb
22
asked Generating Gelfand-Tsetlin patterns
Feb
21
comment Finding connected components in an array
Oh, I am looking forward to that post!
Feb
20
comment Finding connected components in an array
Looks interesting, I will try it out tomorrow :). Good performance there!
Feb
16
revised Finding connected components in an array
added 119 characters in body
Feb
16
comment Finding connected components in an array
But, the arrays i am interested in, as in the example, all rows are weakly decreasing, and also the same holds for the two diagonals (in some directions)... this might affect which algorithm performs better...
Feb
16
comment Finding connected components in an array
I added onepts = #[[3]] & /@ weirdNeighbors[array]; tiles = First[#[[4 ;;]]] & /@ weirdNeighbors[array]; tiles = Join @@ tiles; onepts = List /@ (Join @@ onepts); Join[onepts, tiles];
Feb
16
comment Finding connected components in an array
Notice that I modified the accepted answer a bit. Can you please also account for turning your output into the specified form? I tied your code, and it is slower on my machine, (but then, I added code for changing the output.)
Feb
16
comment Finding connected components in an array
Ok, I modified it a bit, see the code in the bottom of the post. Thank you! Works like a charm!
Feb
16
accepted Finding connected components in an array