Hot answers tagged

99

Yes, there was a recently pushed incorrect paclet update that will cause this startup hang. All platforms can be affected, not just Windows. For a workaround, start a standalone kernel (WolframKernel.exe on Windows, WolframKernel in a terminal on Linux; on Mac you will need the full path to the kernel binary, typically a location like /Applications/...


50

Here is a first try to assemble names of important technologies or products around Mathematica. I tried to give appropriate links and a clear description for each entry, so than new users have an idea what these things mean. For some entries though, I just was not able to give an exact definition and especially, how they relate to a normal Mathematica. ...


30

Paclets are downloaded chunks of curated computable data: Load-on-Demand Curated Data Mathematica 6 pioneers the powerful concept of built-in computable data sources. An efficient load-on-demand mechanism makes hundreds of gigabytes of carefully curated and continually updated data immediately available inside Mathematica for use in ...


28

A paclet is a distribution mechanism for resources that contribute to the contents of a package. Most of the paclet machinery is in the PacletManager context, which is not public API. It appears that the only part of paclet functionality presently intended for public use involves PacletInfo.m, a descriptor file for Mathematica applications. This is ...


25

Fixes by Mathematica version. Note that unfixed bugs may apply to earlier versions as well; e.g. TableAlignments -> Left not working also applies to version 7. Version 10.1 Fix syntax highlighting in Trace: Unprotect[Trace]; SyntaxInformation[Trace] = {"ArgumentsPattern" -> {_, _., OptionsPattern[]}}; Protect[Trace]; Fix Incompatibility of Row and ...


23

uh oh, another "work in progress" answer from me that may never be finished. Unevaluated Robby Villegas, Working with Unevaluated Expressions: Unevaluated is not meant to be a function or stable data type. It is to be used as a wrapper on an argument in stage 1, before argument evaluation. It is a signal to the evaluator to suppress the usual ...


22

I'm the one inside the company who suggested RightComposition (and pushed for syntax for Composition and RightComposition). I'm sympathetic to your need, and have wanted the same thing once or twice myself. Given that not much /* and @* code has been written yet, I think it is certainly possible we could have /* parse to LeftComposition. I'm not sure what ...


22

Is it strictly necessary? In most cases, no, but doing so gives us many advantages. Most of those advantages might be worked around with various heuristics. But most importantly, it would have been very difficult to have a robust typesetting system. First, the FrontEnd was always going to need some intermediate representation which is not simply textual. ...


21

Along the lines of Yamareth's answer, but probably an even better technique, is to put the following into $UserBaseDirectory/Kernel/init.m: Needs["JLink`"] SetOptions[InstallJava, JVMArguments->"-Xmx32g"] SetOptions[ReinstallJava, JVMArguments->"-Xmx32g"] ReinstallJava[] By setting the default options, you will get the desired heap size any time you (...


21

Here are four approaches to setting up keyboard shortcuts. The last is the best! AddMenuCommands First examples using notebook manipulation, (as you tried): This example adds a command to the Insert menu, with a key combination Control+U (normally the underline command). This addition just lasts for the session, but could be added to an init file. ...


20

For a workaround, launch a standalone kernel and evaluate PacletSiteUpdate /@ PacletSites[] PacletUpdate["EntityFramework"] More detailed instructions can be found here (except substitute "CloudObject" with "EntityFramework"). Please see also this post on Wolfram Community for step by step instructions on all platforms.


19

[Edit: I updated this question to fix a couple of mistakes and to reflect the behavior in 10.3. -jf] The question I'll answer here is "How is the cell style of a given cell resolved." There are several other questions one could ask about option resolution, and I won't attempt to answer all of them here, but I will show in some exhaustive detail, at the ...


19

You can save a lot of space in the Documentation directory by using Delete All Output on all the larger ones and by using disk compression. For example, the v7 documentation Notebook for ContourPlot is 27.7MB, but after deleting output it is only 192k, and after NTFS compression only 72k. Doing this will require evaluating the documentation page before you ...


19

The full form of ?@ is Information["@", LongForm -> False]. LongForm -> False means use the short form of Information, which calls Names["@"] (or a utility that both Information and Names use) to find the symbols which it should retrieve. Names interprets "@" as match one or more characters, but not uppercase letters So you are getting a short ...


18

I'm adding an alternate solution for Mac, as the suggested answer did not work for me. It might be due to me force quitting it prior to looking for a solution. This method is a bit of a scorched earth process though. In Finder go to ~/Library/Mathematica. Once there delete the Paclets folder. Next start up Mathematica again. Create a blank worksheet. ...


17

I found the solution. Mathematica is set up to use the font KLIpIqaDmey. The tip-off is in the UnicodeFontMapping.tr file referenced in the question. The header reads: @@resource UnicodeFontMapping Mathematica: Times Automatic Mathematica: (Times Courier) Automatic Mathematica: (Mathematica1 Mathematica1Mono) Automatic Mathematica: (Mathematica2 ...


17

This posting is not a complete answer. Rather, it is a spelunking report concerning the kernel initialization sequence in version 11.0.1 as it relates to automatic paclet updating. In summary, every three days the system initialization sequence will automatically update paclets that are loaded from $PacletSite. $PacletSite is normally http://pacletserver....


16

It's because there are a lot of forms in mathematics, and Mathematica tries to follow mathematical notation as far as possible. Note that this is not entirely specific to Mathematica; for example most programming languages allow e.g. additions to be expressed as 2+3 rather than plus(2,3). Some programming languages also allow to overload existing operators, ...


15

Does running Quit[] do what you want?


15

Here goes my conjecture but I would welcome any opinion or clarification by people in the know. PackedArray stores data in a computation-efficient way. It still represents a List in all other respects, and is displayed as one. Some Lists are generated as PackedArrays silently where Mathematica decides it possible and helpful, and unpacked if an operation ...


14

I've certainly encountered this behavior before. While I can't speak authoritatively, I'd think this is as designed, although it does introduce certain inconsistency. I also think that this issue is a result of clash of cultures: the end user - oriented one from the earlier days of Mathematica, and the one coming from standard software-engineering practices. ...


14

Not really an answer and I may have to delete it, but...I had something of a different reaction to this business of the front end having its own parser, circa 2004. For motivation I recommend the original. I knew a front end that swallowed a kernel. I don't know why it swallowed a kernel. They taste infernal. I knew a front end that swallowed a ...


14

After some spelunking, I found a file which contains a lot of initialization code, including reading the kernel init.m file, loading Autoload packages, loading anything set with the -initfile option, starting the paclet manager (which may autoload packages), and many other things. It is SystemFiles/Kernel/SystemResources/$SystemID/sysinit.m Towards the ...


14

Apparently, Throw is deactivated during kernel initialization. The following function can determine if Throw is inoperative: throwInoperativeQ[] := CheckAll[Catch[Throw[False]], # /. Null -> True &] The undocumented function CheckAll is used here because Check also appears to be unreliable when Throw is inoperative. If we make the assumption that ...


13

Using this site as my rubber duck and attempting to answer my own questions: (1) Reason for existing behavior One may want to be able to do this: heldRow = HoldForm @* Row @* List; (* version 10 syntax *) x = 7; Block[{x}, heldRow[x + x + x, x^2*x^3] ] 3 xx^5 (* proposed behavior would yield: x+x+xx^2 x^3 *) My counterargument: this ...


13

An extended comment. I'm not sure if this has been realized, please correct me if it has. The result of the Divide[a,b] operation is not the same as the first 3 which are identical. {a, b} = List @@ RandomReal[{-50, 50}, {2, 1*^7}]; x1 = a/b; x2 = a b^-1; x3 = a/b; x4 = Divide[a, b]; Now... Tally[x1 - x2] Tally[x2 - x3] Both give 10^7 zeros. Tally[x3 ...


13

Since Windows doesn't display directory sizes for me I wrote a tiny utility to let Mathematica display them in a collapsible tree form (code at the bottom). I opened up some candidates for deletion, but you should try them first by moving the specific directories out of the MMA directory structure. As Image_doctor said, the documentation is a good sized ...


13

Half of it appears to be in ../Documentation , you could delete that and look everything up on the Wolfram site on the web


13

Option hierarchy Quoting John Fultz: Options work on an inheritance model. ... It all starts someplace. That would be the hard-coded option values in the front end C code. The root of the inheritance of options. Then one typically thinks of $FrontEnd as being the next level down, but there's another level in between. That is $...


13

You are looking for $CloudEvaluation system variable. For example: $CloudEvaluation (* False *) and CloudEvaluate[$CloudEvaluation] (* True *)


Only top voted, non community-wiki answers of a minimum length are eligible