# All Questions

6 views

### find position of nearest nonzero element in an array (functionally)

Given an array sel and an index position i0, how can I find the position of the nearest (left or right) nonzero element? I'm ...
6 views

### Combined ListPlot3D using arrays of different length

I have three parts of a ListPlot3D that I would like to combine. The problem is, the middle part has more points in one dimension than the other two, which means I can't combine them easily to plot ...
10 views

### aborting at a message, but still save data

This may be an easy question, but I can't find it anywhere. I have a code which solves linear equations in a do loop (possibly compiled) using LinearSolve. To save the results I use Reap and Sow. It ...
8 views

### No connection to WoframAlpha with v10.1

I have a problem with my connection to WolframAlpha with the new version 10.1. And I can't figure out what causes it, because it works with version 10.0. Also, I have a connection to the data ...
27 views

### Contour Integration along a contour containing two branch points

I need to compute following contour integrations: $$f(u)=\oint_\alpha dz \sqrt{z^3+z+u} \qquad ; \qquad g(u)=\oint_\beta dz \sqrt{z^3+z+u}$$ In which $\alpha$ and $\beta$ are two contours in ...
28 views

### Imaginary terms in the derivative of Jacobi theta function (2) on the real line

I am trying to calculate/plot the derivative of the second Jacobi theta function $d\theta_2(0, e^{-\pi t} )/dt$. Calculating or plotting the function itself works fine: ...
31 views

### How to make a 3d surface/point plot with color based on a list

This is my data: ...
51 views

### How to implement symbolic Ramanujan's summation in Mathematica?

How to implement Ramanujan's summation in symbolic form in Mathematica? For instance, I want as input the function $f(x)=x$, as output $-1/12$, as input $f(x)=1/x$, as output $\gamma$ (Euler's ...
79 views

### how can I create function which contains a ODE system and its numeric solution

I have create a function like this,which contains a ode system. And I want to know the effect of different parameters ...
72 views

### How to make multiple if statements? [on hold]

I know Mathematica's if format is if[test, then result, else alternative], like for example y:=If[RandomReal[]<0.2,1,3.14] Would take a random real number ...
18 views

### Proof left-continuous of fucntion [on hold]

Hello everybody I have really no idea how to solve this question:
50 views

### How would I go about simulating conditional random birth 100 times?

So I have the following scenario: Assume you have this organism that reproduces by itself. An organism either reproduces 0, 1, 2, or 3 organisms at a time. Assume they're asexual and reproduce only ...
30 views

### Manipulate excel file and plot

I have a number of .csv files that have the following format: I want to do the following: ignore the last two rows sort all the remaining rows w.r.t the 2nd ...
33 views

### How can I crawl the facebook social network?

Before the Wolfram+Facebook API is shut down I'd like to scrape the largest possible friend network I can, starting with a certain "UserId" and doing a breadth first search (going outward to as many ...
22 views

### SocialMediaData related functions don't save authentication data

Is there any way to stop SocialMediaData and ServiceExecute from making me re-authenticate every time? For example, say I have ...
42 views

### DiscretePlot - adjusting the scale on Y axis to log with prescribed spacing

I have this picture of a residual Plot I am trying to reproduce (Y axis scale should be the same as in my plot): The code I ...
46 views

### Transcendental Equation

After playing around with The Planck radiation law for the spectral energy density, (differentiation and setting equal to 0 to find the maximum wavelength"x") I'm stuck on how to deal with what I'm ...
59 views

### Real part of a sum

I would like to take the real part of the following expression: Sum[(a[i] + I b[i]) r^i/(r^2 + z^2)^i, {i, 0, 2 n}] where all of ...
35 views

### Computing triple integrals two different ways [on hold]

I tried to compute a triple integral symbolically like this: (forgive the TeX - couldn't figure out how to show what it looks like in Mathematica)  \int_0^{\pi} \int_0^{2\pi} \int_0^{122100000} ...
24 views

### If statement with multiple expressions to be evaluated [on hold]

Below is the code that I would like, but I am unsure of how to get it. I'm trying to run multiple expressions within the if statement and don't know how. ...
37 views

### Plot axes are not exported to SVG properly in Mathematica 10.1

In the past, I was able to export Mathematica plots as SVG files with relative ease. However, when I tried to do this recently, I found that the text in the plot axes was rendered completely ...
26 views

### I can create an H2 database with the H2 Console, but I can't find the database with MMA

I can create an H2(Server) database using the tool that H2 provides, but although i can create a memory based H2 database with the Database Explorer, when I try to create a connection to the ...
17 views

### How to export 3D graphics to any 3D model format while preserving texture?

This question was asked previously but never answered. In recent posts people are finally talking about povray again, so I thought I'd repost but generalize the question to any 3D modeling format?
23 views

### How to combine Toggler and Button?

The Play function defines a toggle button to start and stop: I'm trying to emulate that, but with a single button. I feel like this is a common enough task that this question should be answered ...
53 views

### Getting coordinates of a embedded graph [on hold]

I have to show how spring embedding works by displaying step-by-step images of a GridGraph[10x10] being embedded from a initial circular form to the final form, which should look somewhat like this: ...
37 views

### How to force Mathematica to interpret a file as HTML?

Some web pages do not explicitly contain the file extension "html" but is formatted that way (like this one). If I saved this page to my computer then Mathematica could parse it correctly. But if I ...
56 views

### Controlling colors of points in ListPlot

I have a collection of points I want to plot using ListPlot[]. I would like each individual point to be a certain color depending on a key value that is based on a list separate from the points. As a ...
50 views

### Problems with TimelinePlot

I'm trying to play with the example in this recent blog post, but I'm having a few basic issues with TimelinePlot: Labels are getting cut off: How can I get ...
20 views

### LieART package Sp branching rules [on hold]

I have been trying to find several branching rules using LieART for Mathematica, more specifically from Cn to An. I have not been able to do so, with Mathematica telling me that either An is not a ...
41 views

### How to scrape image search engines?

I'd like to download highest resolution images possible from the search results like these: ...
28 views

### Is there a way to create named ranges for spreadsheet exports?

I am trying to figure out whether I can tell Mathematica to name ranges for data that I am exporting? I want to use this data in CPLEX, which unfortunately doesn't allow the use of the R1C1 notation, ...
47 views

### Memory leak when looping over FindInstance

When I run the following (simplified) code with FindInstance, my MemoryInUse is constantly increasing: ...
29 views

### How do I numerically integrate over a data set that has uncertainties? [on hold]

I have a 1D data set {xi, yi} with no uncertainties in xi and with uncertainties dyi in yi. The resulting discrete function is monotonic and relatively smooth and I would like to integrate the ...
62 views

### Manipulate with multiple locators [on hold]

How can I work with tables/lists of Locators under manipulate? Note this is very similar to this question: http://mathematica.stackexchange.com/a/51956/2079 The ...
58 views

### Faster variant of Reduce for finding zeros of holomorphic functions in a region

I'm currently using Reduce to find zeros of a function in a region on a complex plane: ...
28 views

### How to append when function outputs are two different arrays?

I have written the following lines of code to generate two vectors $y$ and $poa$. I would like to repeatedly run different instances of the procedure, appending all the resulting $y$s to form one long ...
86 views

### How to Box only a part of a Graphics3D

In the following example, I would like to Boxed only the RegionPlot3D, and not the Sphere. ...
22 views

### Static Forces With Calculations of Diagrams [on hold]

How can I calculate the reactions and draw Shear force, axial force and bending momentum diagrams..?
89 views

### ImageApply Performance Difference

How come the timing difference between these calls is so big? (0.2 and 39 seconds on my computer) ImageApply[q3, img] ImageApply[q3[#] &, img] Where ...
37 views

### Why does a transform from polar coordinates using TransformedField not agree with by-hand calculation?

I have the following (simple) system of ODE's that I wish to express in Cartesian coordinates: \begin{align*} r' &= r(1-r)\\ \theta' &= 1 \end{align*} Working it out by hand, by ...
26 views

### Detecting deviations in a list of points

Say that I have a list of evenly-spaced points that I want to plot using ListLinePlot. To generate them, I am using a function that works with relatively low ...
26 views

### upper limit with PlotStyle in GeoListPlot in v10.1

Confirmed bug in v10.1 Let's start with the code below: ...
21 views

### How to write each component? [on hold]

I would be appreciate if someone can help me. Assume that I have (0, u y, u + u y) and I want to write each component in order of y^i when y^2=1. So it changes to (0, 0, 0, u, u, u). What should I ...
26 views

### RegionPlot3D exponentiation issue [Mathematica 10] [on hold]

For some reason, the following code returns an empty graph: RegionPlot3D[x^2 + E^(y^2) + z^2 <= 1, {x, -2, 2}, {y, -2, 2}, {z, -2, 2}] But ...
32 views

### Plotting 2nd order ODE solution for specific values of constants

Suppose that I have a 2nd order, linear ODE and I want to plot the solution I found using DSolve. How can I plot giving specific values of ...
22 views

### How to define more “natural” partial derivative symbols? [duplicate]

I am struggling to use the notation package to display my input in a more natural notation.Of course,the following code fail to meet the need.How could I develop it? ...
35 views

### Data plotting to estimate answers

I have some data such that I am estimating the time taken by system to reach at some stage. For example. 1 sec to reach at stage 1, 3 seconds to reach at stage 2, 5 seconds to reach at stage 3 and so ...
22 views

### Kronecker Delta and Contraction in Feyncalc

I am trying to simplify a rather complicated equation involving vectors and kronecker delta. I am trying to use Feyncalc for this purpose, but somehow i am not able to do it using Contract/Trick. ...