Unanswered Questions

49
votes
0answers
895 views

Is it possible to customize the Suggestions Bar?

I'd like to be able to customize the Suggestions Bar in v9.0 to provide recommendations of my own. Possible example: when doing unit calculations, I'd like it to suggest converting the answer to ...
41
votes
0answers
960 views

Numbered equations/formulas

How do you number equations in Mathematica notebooks so that they are exported correctly into latex? In case you don't know how to put numbered equations here is quick review. Open a new notebook ...
37
votes
0answers
506 views

Is this 30% slowdown in Mathematica 10 due to DownValues lookup time?

Running several numerical self-programmed packages I realized already some time ago that Mathematica 10 needed between 20 and 40% more time. I did already report this of course with a simple example ...
34
votes
0answers
437 views

Is this the most effective and efficient programming style for prototyping (a ray tracer) in Mathematica?

I am trying out Mathematica as a prototyping tool. As an initial exercise I have put together a brute force ray tracer, with a view to using Mathematica's built in probability distribution functions ...
32
votes
0answers
585 views

How is pattern specificity decided?

Mathematica has a notion of pattern specificity, which is a partial ordering on patterns. The rules (e.g. DownValues, ...
27
votes
0answers
456 views

Why is StringExpression faster than RegularExpression?

Edit: as noted by Albert Retey the performance difference is only seen when sub expression extraction is performed. If this test is used below the timings are similar: ...
26
votes
0answers
603 views

What calendar is Mathematica using for dates in the distant past?

It appears that Mathematica treats all dates as proleptic Gregorian dates by default, a hypothesis that can be easily tested by using AbsoluteTime to compute the ...
24
votes
0answers
226 views

Managing Stack Exchange favorites via Documentation Center

My Stack Exchange favorites are getting bigger and bigger. It is becoming unmanageable and is getting hard to find what I look for. A related question is Sort favorite questions. Is it possible to ...
21
votes
0answers
224 views

StringCases is Confused with Patterns in Version 10.0.1

I observed the following with StringCases when trying to use rules/patterns. Here is a screenshot of the behavior: Not only is the pattern highlighted in red, ...
21
votes
0answers
288 views

Why does list assignment with a packed array result in unpacked values?

This is another question on the design choices in Mathematica. I understand that without direct reply from the developers it may not be possible to give a definitive and exhaustive answer to "why" ...
21
votes
0answers
2k views

Simplify matrix algebra

I'm trying to simplify some matrix linear algebra, for example, simplify $$\big(a1\times(A1\cdot A2)\big)\cdot\Big(a2\times A3\cdot A4+(a3\times A5)\cdot(a4\times A6)\Big)^{T}$$ where lower case ...
21
votes
0answers
450 views

Changing FrontEnd automatic scrolling in version 8

In Mathematica versions < 8, the FrontEnd has a very intelligent behavior: On evaluation, it by default automatically scrolls down the Notebook window to the last printed Output cell but also ...
19
votes
0answers
237 views

Are greek symbols causing different evaluation?

I've updated today to Mathematica 9.0.1.0 from version 8 and found something that absolutely confuses me. Let us define a piecewise function: ...
18
votes
0answers
463 views

Proving the hairy ball theorem using xAct

I would like to formally prove the hairy ball theorem in Mathematica, initially just for $S^2$, and then see about generalizing. An approach I thought about to use the xAct package to define $S^2$ ...
18
votes
0answers
675 views

How would I improve this Karaoke machine code?

I was looking at a large collection of Import/Export user suggestions the other day and it dawned on me that we finally have MIDI import in Mathematica 9, which is rather interesting since MIDI ...

15 30 50 per page