All Questions

36
votes
4answers
3k views

How to change the default ColorData used in Mathematica's Plot?

This question leads on from the recent question What are the standard colors for plots in Mathematica? There it was determined that the default color palette used by ...
28
votes
4answers
3k views

How can I make an X-Y scatter plot with histograms next to the X-Y axes?

I just saw a nice plot there: How could I implement that in Mathematica — by which I mean the plot structure, not so much the styling.
31
votes
6answers
2k views

How to visualize/edit a big matrix as a table?

Is it possible to visualize/edit a big matrix as a table ? I often end up exporting/copying big tables to Excel for seeing them, but I would prefer to stay in Mathematica and have a similar view as in ...
31
votes
1answer
1k views

How can all those tiny polygons generated by RegionPlot be joined into a single FilledCurve?

RegionPlot will usually generate a large number of tiny polygons for filling the region: ...
26
votes
7answers
2k views

Simpler input for the new unit support

I've been playing with the new unit support in Mathematica 9. It seems very useful, but the syntax is very verbose. Instead of typing: ...
30
votes
5answers
2k views

Are there any cases when For[] loops are reasonable?

To my mind the only reason for the existence of For[] loops in Mathematica is to allow new users with some experience in procedural programming languages to write ...
28
votes
3answers
629 views

Are there guidelines for avoiding the unpacking of a packed array?

Packed arrays are very useful because they save memory and generally allow speedier and more efficient calculation times. If a list of data currently stored as a packed array is unpacked, it can slow ...
28
votes
3answers
2k views

Data Table Manipulation in Mathematica

I am a statistician searching for an efficient way to select rows or columns from a table of data in Mathematica. Let me pose the question in 2 parts with a SQL-style table of data: ...
26
votes
6answers
2k views

How to select minimal subsets?

I am a newbie, so please point me in the right direction if you feel this question has been answered somewhere else before. Here goes: Suppose I have a list like this: ...
34
votes
2answers
736 views

Why is the new PositionIndex horribly slow?

This issue has largely been mitigated in 10.0.1. New timings for the final test below are: ...
21
votes
3answers
1k views

Generating graphs interactively (GUI)

I want to create graphs interactively using a GUI. I thought of using a ClickPane[] environment. The code I have (in part borrowed from the Documentation) works ...
33
votes
5answers
779 views

Items known by CurrentValue

CurrentValue can be used to poll the state of numerous system values such as the mouse position. Its help page doesn't list all possible items, though. An item like ...
24
votes
4answers
2k views

How to make a drop-shadow for Graphics3D objects

What's the best way to make a drop shadow for a 3D object? image = Graphics3D[Sphere[], Boxed -> False] I can get a blurry black outline of this: ...
25
votes
3answers
747 views

How do I add new menuitems to menus?

What are some complete examples of what one would include in a FrontEnd init.m that would make use of FrontEnd`AddMenuCommands ...
14
votes
5answers
722 views

Iterate until condition is met

I want to find the first 5 prime numbers of the form $n^6 + 1091$. I have used this code: Timing[Select[Table[n^6 + 1091, {n, 10000}], PrimeQ, 5]] Which gives ...
17
votes
4answers
2k views

How to get intersection values from a parametric graph?

I have this graphed: ParametricPlot[{2.4*Cos[t] + 1.6*Cos[3 t/2], 2.4*Sin[t] - 1.6 Sin[3 t/2]}, {t, 0, 4*Pi}] It is a star, and the lines cross each other ...
20
votes
4answers
2k views

Real Size Image Printing

I am generating a complicated graphics with Mathematica, but with objects of given sizes (e.g. a line of length 1 inch, between two points). I want to make sure that when I export the graphics, e.g. ...
18
votes
4answers
910 views

How to collect result continuously (interruptible calculation) when running parallel calculations?

This is the most common pattern to compute a table of results: Table[function[p], {p, parameters}] (regardless of how it's implemented, it could be a ...
16
votes
2answers
7k views

How to make Jacobian automatically in Mathematica

If we have two vectors, a and b, how can I make Jacobian matrix automatically in Mathematica? $$ a=\left( \begin{array}{c} \text{x1}^3+2\text{x2}^2 \\ 3\text{x1}^4+7\text{x2} \end{array} ...
14
votes
3answers
2k views

Solving a Volterra integral equation numerically

I would like to solve for $P(t)$, in Mathematica, a Volterra integral equation of the 2nd kind. It is: $$P(t) = R_0(t) + \int_0^t P(t') R_0(t-t')dt'$$ I know the function $R_0$ and would ...
14
votes
3answers
2k views

I'd like to display field lines for a point charge in 3 dimensions

I'd like to display field lines for a point charge in 3 dimensions. Not a force field (short arrows) but continuous field lines that start on the charge.
23
votes
7answers
4k views

Sizing cells in a GraphicsGrid/GraphicsRow

I would like to add a colour bar to a plot. I tried to use GraphicsRow for this. In a GraphicsRow, each item is given the same ...
16
votes
7answers
1k views

Find continuous sequences inside a list

I have a list which is something like this: {3,4,5,6,7,10,11,12,15,16,17,19,20,21,22,23,24,42,43,44,45,46} What I'd like to to is get the intervals which are in ...
16
votes
3answers
962 views

Removing unwanted appearance of underlying mesh

Let us first define two positive definite matrices: M1 = {{2, -6}, {4, 8}}; M2 = {{2, 3}, {4, 8}}; then set two points ...
24
votes
4answers
2k views

Is it possible to prerender animation in Wolfram Mathematica?

I have a DensityPlot which is evaluated for a long time. I wish to use it with animation, but it is absolutely inapropriate. Is it possible to render animation ...
16
votes
1answer
688 views

How can I conveniently call igraph through RLink?

Mathematica has lots of functions for working with graphs, but this functionality is not yet as mature as the igraph library. It is useful to have access to igraph from Mathematica, both for ...
12
votes
2answers
2k views

Plotting complex Sine

I've got another plotting problem. I want to plot Sin[z] where z is complex. So, I've tried the following: ...
23
votes
1answer
537 views

Prefix operator with low precedence

The question is simple, but I will elaborate on the background as well for those interested in the idea: How to define a new operator with specified precedence value? Background Mathematica was ...
16
votes
5answers
1k views

Having the derivative be an operator

How do I create an operator which acts like a derivative to everything to the right of it: for example: $ \left( \partial_x + \partial_y + z \right ) x \psi $ How do I make that evaluate to: $x ...
12
votes
3answers
2k views

How do I use Map for a function with two arguments?

I'm a newbie who tries to be a good boy, and use Map instead of writing out a list of functions. I have a table I want to Map ...
10
votes
5answers
4k views

Filling between boundaries

I would like to visualize what it graphically means to integrate between two boundary values. Therefor I'd like to make a Filling between these two values. Is there a way to get this done?
9
votes
2answers
896 views

How do I automatically evaluate a cell when a notebook is opened?

I'm trying to put together a GUI in Mathematica and need to evaluate one cell to kick that off. Is there a way to automatically evaluate that cell when the notebook is opened? Here is an example of ...
18
votes
1answer
325 views

Copying one symbol into another

I would like to know how can I completely copy one Symbol to another. When I say copy, a refer to UpValues, DownValues, ...
17
votes
3answers
2k views

Plotting piecewise function with distinct colors in each section

I have a piecewise function that I would like to plot but I was wondering if it is possible that each part of the function that is plotted when its corresponding condition is true be plotted with a ...
13
votes
1answer
368 views

Is it possible to use Begin and End inside a Manipulate?

May be someone can explain why I can't use Begin["context`"] and End[] inside a Manipulate ...
10
votes
3answers
796 views

PolarPlot render oddities

I apologize if this is a obvious question and answer, I don't often use Mathematica to display plots or graphics in general to be honest. So, I was tutoring my cousin yesterday in relation to Polar ...
9
votes
3answers
689 views

Problem with ParametricPlot

I'm ploting gear curves (http://mathworld.wolfram.com/GearCurve.html), and I observe that for some parameter values ParametricPlot[] does not plot all the teeth: ...
7
votes
3answers
588 views

Retrieving the ImagePadding in absolute units

Consider the following graphic: g = Graphics[Circle[], Frame -> True, FrameLabel -> {"one", "two"}] Retrieving the ...
6
votes
2answers
444 views

Displaying index as subscript on output: e.g. C[i] -> C_i with Notation[…] or Interpretation[..]?

You have all convinced me not to type in formulas with subscripts. However, in order to be able to match the subscripts in my whiteboard math, I figure a 2nd best solution is to want to display ...
6
votes
1answer
1k views

Mathematica won't give eigenvectors but Wolfram Alpha will? What am I doing wrong?

If I ask Mathematica to find the eigenvectors and eigenvalues of the matrix: ...
13
votes
1answer
859 views

Plot showing discontinuity where it shouldn't

I was trying to integrate a continuous function with a kink and I did it two ways and both ways the plot of the result shows a discontinuity. I also later want to differentiate the Integrated ...
12
votes
3answers
1k views

Why is ContourPlot not displaying this curve?

I am using the general form of a second-degree plane curve: $$Ax^2+2Bxy + Cy^2+2Dx + 2Ey + F = 0$$ I want to randomly generate plane curves of this form, so I am using ...
7
votes
3answers
1k views

Finding the number of solutions to a diophantine equation

I want to count total number of the natural solutions (different from 0) of the equation $2x + 3y + z = 100$, but don't know how. How can I calculate it using Mathematica? I tried: ...
8
votes
2answers
496 views

Why does Integrate declare a convergent integral divergent?

When I try this command Integrate[1/Sqrt[(s^2 - u)^2 - 1], {s, m, Infinity}, Assumptions -> u > 2 && m > 10] Mathematica declares that the ...
7
votes
1answer
261 views

Confused by (apparent) inconsistent precision

$$ e^{\pi \sqrt{163}} \approx 262537412640768743.99999999999925 $$ E^(Pi Sqrt[163.0]) N[E^(Pi Sqrt[163.0]), 35] NumberForm[E^(Pi Sqrt[163.]), 35] returns ...
4
votes
2answers
346 views

Coloring a shape according to a function

I would like to create a $2D$ shape, say an ellipse, where each point in the ellipse is colored according a RGB function, so at point ...
4
votes
3answers
307 views

How can I compare a dynamic variable with a literal in Mathematica?

I'm doing a Mathematica Notebook and I want to make an alarm clock. Something like this: ...
3
votes
1answer
197 views

When does the real part of Zeta vanish on the critical line?

This seems to be a quite a simple problem but I cannot make it work. I am trying to find all values within a given range for which the real part of the Zeta function vanishes on the line: ...
2
votes
2answers
240 views

Position function not always retuning an answer even with no apparent problems

I'm having some problems with Position. Sometimes it will give an empty list instead of the actual position of the element I am looking for when that element is ...
97
votes
3answers
12k views

How to create word clouds?

Word clouds are rather useless fancy and visually appealing plots, where words are plotted with different sizes according to their frequency in a corpus. Many applications exist out there (Wordle, ...

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