## Top new questions this week:

### How to select the fastest approach for large numerical data computations?

I really love the flexibility of Mathematica: there are several ways to perform one task. However, to get the performance of the intense numeric calculation, it can ...

list-manipulation performance-tuning numerics pattern-matching functional-style

### Font style inconsistency on "number sign" (hashtag) and "at symbol"

Why number sign "#" (known as hashtag symbol on social media) or at sign "@" are not consistent with the ...

style fonts

### Display Number with SI prefixes

I have a number of val = 0.000015783 which represents a current value in Amps. I want to display it with 3 significant digits and with SI prefixes instead of the ...

formatting

### Split in non-overlapping sub-lists with elements within an interval from the first member

I want to split a large ordered list into consecutive non-overlapping sub-lists, such that all elements are within an interval from the first member of the sub-list . For example: ...

list-manipulation sublist

### Performance of pure function - Best way to define a function?

In general, to define a function, we often use f[x_]. Another way is to use pure function (full form and shorthand). I want to test the performance of these ...

functions performance-tuning functional-style pure

### Are arbitrary expressions allowed as input arguments in Compile?

I made a typo when entering code for Compile. I thought it should have resulted in an error when the code was compiled, but it didn't. It did give an error when ...

syntax compile

### Stacked/Percentile Bar Chart formatting

There seem to be a lot of questions regarding the formatting of bar charts. Sadly, I couldn't find solutions to my problems, despite all the skimming. Apologies if I missed something. Problem ...

output-formatting charts

## Greatest hits from previous weeks:

### How to make a spiroglyphic?

Some (older) members of this group might remember playing vinyl LP records. Recently, at the Abbey Road studio there was a spiroglyphics coloring book for sale. It looks like a nice programming ...

image-processing code-request generative-art

### Elegant operations on matrix rows and columns

Question The Mathematica tutorial has a section 'Basic Matrix Operations', describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ...

list-manipulation matrix array faq

### How can I improve Mathematica's resolution on a macbook retina display?

Mathematica 9.0 looks a bit fuzzy on the retina screen, how can I increase the resolution? Here another screenshot showing a direct comparison between the browser and Mathematica

front-end version-9 mac-os-x

### How to manipulate 2D plots?

When it comes to visual analysis, large datasets or data with intricate internal details often makes plotting in 2D useless, as the outcome is either just a fraction of the full dataset, or no details ...

plotting graphics dynamic gui-construction

### Find eigen energies of time-independent Schrödinger equation

I'm trying to get the eigenvalues of a one dimensional time-independent Schrödinger equation, $-\frac{h^2}{2m_0}\frac{d^2\psi}{dx^2}+U(x)~\psi=Ei~\psi$ where U(x) is some potential and Ei is the ...

equation-solving physics parametric-functions

### Finding unit tangent, normal, and binormal vectors for a given r(t)

For my Calc III class, I need to find $T(t), N(t)$, and $B(t)$ for $t=1, 2$, and $-1$, given $r(t)=\{t,t^2,t^3\}$. I've got Mathematica, but I've never used it before and I'm not sure how to coerce ...

equation-solving calculus-and-analysis geometry vector-calculus homework

### How to create a new "person curve"?

Wolfram|Alpha has a whole collection¹ of parametric curves that create images of famous people. To see them, enter WolframAlpha["person curve"] into a Mathematica ...

graphics image-processing algorithm wolfram-alpha-queries generative-art

## Can you answer these questions?

### Update Matrix entry from Java

I found the following example online (which works fine) for sending commands from Java: ...

### Extension of Coefficient to variable exponents

Say I have an expression that is a polynomial in a variable, for example in the variable $x$, in which terms appear for which the exponent of $x$ also includes variables. For example: ...

polynomials variable coefficients