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visits member for 2 years, 10 months
seen Dec 22 at 22:55

Dec
18
comment coordinate system problem
Yes, I think ImageData is the best function if you need to access directly the pixel values. Check the documentation, maybe some of its options are useful for your case of use.
Dec
18
comment coordinate system problem
I see, that's a Graphics tool, and those are "plot" coordinates, so they start bottom left. That means that you have to do height - coordY to get the row number.
Dec
18
comment coordinate system problem
How do you access the pixels of the image? Remember that you can see an image as a matrix, where the first row is the top row of pixels. This is why ImageData[image][[1]] represents the top row.
Dec
18
comment Difference between Association and Dispatch
Association keys cannot be patterns (they behave like they had Verbatim), that's the main difference with common rules. Try _Integer /. Association@{_Integer -> Null}, you will get the Null value.
Dec
18
comment Why is C-compiled (but not WVM-compiled) code so slow in Manipulate?
I don't have anymore M8, so cannot test there, but tested it in 9 and 10 and worked fine.
Dec
17
comment Animate skips frames and hard to control speed.
Also check ArrayPlot, I think it is faster than MatrixPlot, and you might try to precompute stuff, like the Prime[Range[400]], not big overhead, but you can keep the list in a variable. Also writing it all as an expression is slightly faster than with pure functions just applied once.
Dec
1
comment How should I correct in the sintaxis of URLExecute
Second parameter of URLExecute are GET/POST parameters. Your "Method" and "Headers" should be options of URLExecute, not the second parameter.
Dec
1
comment ImportString JSON possible bug
Are you using Windows? I've seen that before in a Windows computer. He got rid of the problem after updating the operative system, but not sure if it was just coincidence.
Dec
1
comment Using SendMail with new Google Security Rules
SendMail uses SMTP, and as far as I see, that protocol is under the "less secure apps" yet.
Nov
27
comment Compact Map of USA with Alaska and Hawaii shown under California
Unfortunate, Inset is the best answer to your question yet. Maybe an improvement could be placing it automatically using GeoDestination + GeoDisplacement instead of writing yourself the coordinates for the Inset.
Mar
7
comment How to completely reinstall Wolfram Workbench on linux
Did you remove the preferences directory /home/.../.eclipse? Maybe it helps to clean it completely.
Oct
18
comment How do you convert a string containing a number in C scientific notation to a Mathematica number?
@GeorgeWolfe because it might lead you to a code leak. What if there is dangerous code within the string? Or something innocent like a equal sign (=) may set any of your variables.
Jun
19
comment Why do I keep getting 0.06 with WorkingPrecision->1?
Yep, I was also trying to understand where the 0.06 came from, and if you try InputForm /@ Union[RandomReal[UniformDistribution[], 1000, WorkingPrecision -> 1]] you will see the actual real numbers you get, and all are fractions of 16.
May
10
comment Interdependent controls in Manipulate
@Mr.Wizard I would say this is similar to this one: mathematica.stackexchange.com/questions/4212/…
May
10
comment What format to use to store expressions in database?
For example ToString[x, InputForm] will let you go back to MMA but it would be better to answer @tkott to get a better answer.
May
3
comment Finding all dictionary words that can be made with a given set of characters (Wordfeud/Scrabble)
I don't use IgnoreCase because Im doing the pattern test outside DictonaryLookup`.
May
3
comment Thousands separator (comma) option for NumberString/StringCases?
ImportString does many tricks, but sometimes is too slow. Anyway it's a very good option if you don't want to build your own transformation.
May
3
comment Having the derivative be an operator
@celtschk you are totally right. I should not answer at nights... I will change it to a non-conmutative way.
Apr
30
comment Behavior of ImportString in Mathematica
+1. InputForm rules!
Apr
23
comment How to solve a problem in relative motion?
When you use recursion in that way, you need to define everything for the case 0, in your example code you have not defined Pxi[0], Pyf[0], Pxf[0]; define them and you will get rid of the $RecursionLimit error.