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The "WR" in my name has nothing to do with the company that develops Mathematica.


Jan
13
comment Suspecting bug in Parallel Framework
@OleksandrR It is not always a simple matter to bulletproof a pure function body against injected slot references. What about the Send function exhibited in @Szabolcs answer? Named pure function arguments don't help either -- they have problems of their own. Even if such bulletproofing were simple, it is not common practice. I'm not arguing that this behaviour is desirable, but I am saying that we shouldn't expect well-defined behaviour from an ill-defined language construct.
Jan
13
answered Suspecting bug in Parallel Framework
Jan
10
answered StringMatchQ and Alternatives throws message in init.m
Jan
8
comment How to convert from and to UTM coordinates in Mathematica?
I agree with your diagnosis, although the easting should also be 500000 as the OP observes. You might want to mention that the desired result can be obtained using the expression GeoGridPosition[ GeoPosition[{45, 15, 0}, "WGS84"], {"UTMZone33", "CentralScaleFactor" -> 0.9996, "GridOrigin" -> {500000, 0}}].
Jan
7
comment Converting Excel serial dates with NETLink
@Chris Thanks. FYI, I just changed the implementation of excelSerialNumber slightly to eliminate one of those ever-present COM leaks.
Jan
7
revised Converting Excel serial dates with NETLink
fixed one of those pesky COM leaks
Jan
7
answered Converting Excel serial dates with NETLink
Jan
2
comment StringMatchQ and Alternatives throws message in init.m
Apparently Catch doesn't work properly in the init.m file. I get the exhibited error message if I put Catch[Throw[False]] in my init file using V7, V8 or V9. In the example at hand, a Catch is used in StringPattern`Dump`rule1b (called by StringPattern`PatternConvert called by StringMatchQ).
Jan
2
awarded  Nice Answer
Dec
22
answered How do I find the amount of free space on disk?
Dec
21
comment Notation for specifying transformation rules
A couple more alternatives along the suggested lines: f[val_,cond_,res_] := With[{x = x_}, val /. x /; cond :> res] or f[val_,cond_,res_] := val /. # /; cond :> res &@ x_.
Dec
17
comment Are Mathematica 9 units really slow?
@Rojo ... but beginners have no punctuation prejudice to unlearn :D Seriously though, I don't think my answer is truly suitable for use by beginners. The Module / With / symbolic evaluation combination is pretty subtle and a lot to ask of someone unfamiliar with Mathematica. I believe that this kind of problem argues for a "definition-time evaluation" facility in Mathematica: an attribute on a symbol that triggers evaluation within the body of a SetDelayed expression. In this case, it could be used to predigest a unit specification into a more efficient representation.
Dec
17
awarded  Nice Answer
Dec
17
revised Are Mathematica 9 units really slow?
added 1 characters in body
Dec
17
revised Are Mathematica 9 units really slow?
removed the "manual pre-evaluation" method (it didn't work properly)
Dec
17
answered Are Mathematica 9 units really slow?
Dec
8
comment How to make this code threadsafe?
logfileLock must be in a list, i.e. CriticalSection[{logfileLock}, ...].
Dec
8
revised Using .NET 4.0 from NETLink
added the update about Mathematica V9
Dec
8
comment Using .NET 4.0 from NETLink
@telefunkenvf14 I am not aware of any WRI documentation on this topic. I got this information from the relevant Microsoft .NET documentation. Note that these steps are not necessary for Mathematica version 9 as it comes preconfigured this way.
Dec
1
comment Version 9 Blue Screen or Self-Test Error on Windows 7 64-bit
@cormullion As far as I can tell, there is nothing wrong with the font file itself, or the way Windows handles it. The problem lies in the way the file was being installed. Judging from what the installer did to my system, it looks like WRI changed or mistyped the name of the font somewhere along the line (switching dashes to spaces or vice versa). The V8 installer had this problem as well. It is good to see that WRI have nailed it down this time with the patch. Character 0xf361 is in one of the Unicode "private use" areas. Mathematica uses that codepoint for the piecewise bracket.