7,695 reputation
1627
bio website
location
age
visits member for 2 years, 2 months
seen 3 hours ago

10h
comment Colorize Grayscale Image
about 15x faster than my ImageApply :(.
10h
comment Find all roots in range
just looking at the comments @matin maybe should clarify the question as he seems to be aware of ZetaZero and looking for an alternative for some reason.
10h
comment Find all roots in range
Solve gives the result that the roots are +/-Im[ZetaZero[i] - 1/2] for any i>0 (plus the trivial roots) .. at least as I read the question/comments he wants to find the roots without using ZetaZero
11h
comment Find all roots in range
Note this just returns a result in terms of ZetaZero..
15h
comment How do I get a Do function to create a list?
have a look at Reap/Sow
15h
comment How do I get a Do function to create a list?
i'm going to guess you have a Print[] in the do?
19h
comment Open a .txt file in Mathematica
posting the first dozen or so lines from the file might be useful...
19h
comment Open a .txt file in Mathematica
change the extension to nb?
1d
comment using memoization with conditional statement
for your last example do Downvalues[myfunction] after plotting. i expect you will see that you are seperately memorizing the result for each v.
2d
comment Loops for Unit Root Test
UnitRootTest/@px seems to be all you need..
2d
comment Loops for Unit Root Test
does that RandomReal work? Its not a documented usage (likely you mean RandomVariate )?
2d
comment why CopyFile cannot overwrite existing file?
i don't think an undocumented option should be considered a "bug". There may be legitimate reasons, especially for a system related function it may not be robustly tested for all system combinations.
2d
comment using memoization with conditional statement
note for this simple example it may not be apparent if a solution has successfully avoided reevaluating the function definition for each V. For testing purpose you might want to use a fuction like (Pause[10];a V^2+b V+c)
Oct
17
comment Difference between double quotes
this is for sure a front end entry issue that you are getting those slanted quotes at all. Any chance you are running some system level key mapping software, or perhaps some language localization issue?
Oct
16
comment Problems with NDSolve and partial differential equations of several variables
1) you can not specify "infinite" conditions when you are solving over a finite domain. 2) you can not prescribe boundary conditions on both h and w because they are not independent of each other. 3) you should work at simplifying the question down to a smaller example, this is just to much to weed through.
Oct
16
comment Can you compute more terms in this sequence?
at a glance it seems only certain a values ever get used so you might make a a function that remembers it value instead of a table ( a[1]=1 ; a[n_]:=a[n]=Limit[...] ) also b could be precomputed outside the loop, but I doubt that's your bottleneck.
Oct
16
comment Monitor progress of ZIP file extraction
It may prove faster to gin up the system call to use an external utility to unzip to a scratch directory, then import the individual files (Of course then you could readily monitor the individual file progress )
Oct
16
comment Help recreating a gif
note this is inefficiently computing the displacement separately for each segment end (ie 3 times for each vertex). It shouldn't be too much trouble to fix that if performance is an issue.
Oct
16
comment Help recreating a gif
p is a 2d grid of lines and we simply Append a third coordinate according to the function. To use the same function for the color define cf something like cf[a_,x_]:=Hue[ scale df[a,x] ] and do VertexColors->cf[a,#]&/@ # &]
Oct
15
comment Difference between double quotes
what OS, version, etc?