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Jun
22
comment Replacing function in Sum
When using patterns in replacement rules, I recommend the usage of RuleDelayed (that is :>) instead of Rule. It will avoid problems of defined symbols. In your case, if x or y have a definition, your replacement will fail.
Jun
21
awarded  Revival
Jun
21
answered How to stop a .sh script that calls multiple Mathematica scripts?
Jun
19
answered How to check the style and number of arguments like the built-in functions?
May
30
comment Can A Plot Be Overlayed With A Map?
I'm curious too, I would have chosen yours @Mr.Wizard !
May
29
comment Can A Plot Be Overlayed With A Map?
If you want to see the country borders, it has to be at least zoom 2. You can force a particular zoom by using the GeoZoomLevel option, or using an explicit ImageSize that would make the Automatic zoom to be greater than 1.
May
29
comment Shadowing of optional function arguments?
@Guesswhoitis. that's indeed a very good point. Anyway in private functions (if I ever document them :) ), I include the options in the main usage message of the function, and not on each option. But in bigger projects the usage of a Common context is many times necessary.
May
29
comment Shadowing of optional function arguments?
For private options you can also use strings.
May
29
answered Deleting Lonely Numbers From a List
May
28
answered Can A Plot Be Overlayed With A Map?
May
20
awarded  Nice Answer
Feb
13
awarded  Yearling
Jan
22
comment Why does Mathematica add Hold to the result of my user defined symbol?
Just a small comment, you don't need to Unprotect Times or Plus. It is better if you do: mat /: Times[c_, mat[0]] := mat[0].
Jan
9
comment Computing a sequence by recurrence
Is k1 an arbitrary function? If yes, then FoldList which seemed to be the way to do it no longer works.
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
answered Why is C-compiled (but not WVM-compiled) code so slow in Manipulate?