# All Questions

116 views

### Problem with “Lighting” in Mathematica V9

I am showing two figures with Show: ...
182 views

### Why does DSolve return two solutions for my ODE?

I wanted to solve the differential equation: $y’ = (1+2x)\sqrt{y}$ with $y(0) = 1$. It can be done by hand, and to check my answer I typed the following in Mathematica ...
57 views

### Move figures inside function Show

I have a ListLinePlot and a ListPlot3D that I want to combine using Show. I do not know how to change the positions of the figures. Here a toy example: ...
74 views

### Transforming an Optimization Problem into a multi-vector Optimization Problem

I am sitting on an MultiAgent optimization problem trying to solve for a quadruple of variables {e,l,b,c} In a single agent (...
41 views

### Can Manipulate parameters be hidden with an If statement? [duplicate]

I'm making a demonstration with the following code: ...
117 views

### Strange behavior of FourierSinCoefficient

FourierSinCoefficient works normally like this and the result is checked with Integrate. ...
139 views

### DateListPlot in webMathematica doesn't show FrameTicks properly

It seems that DateListPlot when used in webMathematica (3.3.1) show different output than in desktop Mathematica (10.1). In desktop Mathematica, if you evalutate ...
34 views

### Where can I find books about how to use Mathematica solving practical problems? [duplicate]

I can use Mathematica solving commman maths problems like Calculus,Linear Algebra and visualize functions.When I want to improve programming level,I find that most tutorials out of practical ...
3k views

### What are the Wolfram Language's relative strengths for machine learning?

I see a low use of Mathematica in Kaggle competitions. Why would one use the Wolfram Language versus R, Python, or Julia for machine learning? Besides prettier plots and the Manipulate function, ...
92 views

### Animate an object in 3D given by six lines [closed]

I have a structure defined by six line segments connecting six points. The coordinates of the six points change with time. Each coordinate has a formula giving it as a function of time. Three of ...
186 views

### Why can't Mathematica DSolve my equation? [closed]

I am trying to solve $\begin{cases} v(t) = A \cdot e^{kt} \\ v(t) = s'(t) \\ s(0) = 0 \\ v(0) = A \\ v(6000) = 299792458 \\ s(6000) = 2.37 \cdot 10^{16} \end{cases}$ for $A$ and $k$. But neither of ...
68 views

### How to define an expression which is differently evaluated in calculations and printed

Let's say, we have a list: values = {1.2, 0.04, 0.9}; Is it possible to replace 0.04 by some expression, which displays as ...
335 views

### Failure in integrating from an interpolating function!

Consider a list like below: ...
178 views

### Rule transformation between letter and number

I have a global rule as follow: ...
478 views

### Is FrameTicks broken in 10.1.0?

On my system, Mathematica 10.1.0 under Windows, none of these FrameTicks documentation examples work correctly: ...
330 views

### AltGr randomly stops working - Windows 7

My problem is that AltGr just randomly and frequently stops working. I've only seen this problem since the last update (10.1). The only sure way to recover functionality that I've found was to change ...
42 views

### How to adjust the FrameTicks length in DateListPlot?

suppose I have the data for DateListPlot: ...
62 views

### Covariance matrix estimation when number of variables is larger than number of observations

It is well known that the sample covariance matrix estimator results in a singular matrix if the variables is larger than the number of observations. One solution is to apply shrinkage estimators. ...
84 views

### How to define $x^n$ where $x=\pm 1$ and $n\in\mathbb{Z}^{+}$?

I do not know how I can define $x^{n}$ in Mathematica, where $x=\pm 1$ and $n=1,2,3,\ldots$. For even values of $n$ we simply have that $x^{n}=1$. While for odd values of $n$ we have that $x^{n}=x$. ...
83 views

### speed up evaluating a listable function [duplicate]

I apologize in advance for the vagueness, but I can't think of a more descriptive title. I am trying to find the average value of the square of BesselJ[0, x] ...
457 views

### Exporting Dataset to WDX format fails

I reported this to WRI support. Tracking number is CASE:3368636 Official answer is: Thank you for contacting Wolfram Technical Support. This is a known issue and our developers are working on a ...
106 views

### Importing a spreadsheet with infinity values from Excel

I have imported a spreadsheet from Excel that I want to use as an adjacency matrix. I want to use this matrix as the argument in WeightedAdjacencyGraph, so I have ...
40 views

### SetOptions does not give expected result with Grid [duplicate]

Chech this example: ...
146 views

### DiscretizeRegion of ImplicitRegion too small

I have a 2D function that has some sharp peeks within the my domain. I need to find a tight region that contains these sharp peeks. The following is an example of what I would like to do. An example ...
52 views

### Defining a function which takes lists as it arguments and threads over them [closed]

I want to define a function with lists as variables, which has the form like m = Table[2, {i, 5}]; f[x_, y_] = m*x + x*y; x and y are list variables; m is a ...
223 views

### Finding the least positive integer satisfying a quantified statement

I'm studying the convergence of the sequence of functions $f_n:[0,1]\subset\mathbb{R}\to\mathbb{R}$ defined by $$f_n(x)=n^2x(1-x^2)^n$$ for $n\in\mathbb{N}$. These functions converge pointwise to the ...
399 views

### I have the minimum Y value. I want to find the corresponding X value from the list [duplicate]

I have a very big file and contains data in the format of {x,y}. I got the minimum Y value by using data[[All, 2]] // Min[#] & Now I want to get the X value ...
94 views

### NDSolve returns asymmetric solution to a symmetric equation

I am trying to find the potential of a conducting cylindrical electrode by solving the Laplace's equation. Both, the boundary conditions and the equation are symmetric w.r.t. the change $r\to-r$. ...
98 views

### Slow-down encountered for RandomChoice in large lists

I was wondering if anyone could help me to speed up this code snippet which creates simple (sparse) networks by preferential attachment. The algorithm adds a vertex and an edge each time interval. ...
92 views

### Filling Stacked Graph v.10.1

I used a code very similar to the code posted by Kuba stacked line graph with fragmented data ...
220 views

### Create Nested List from tabular data

Im trying to create a nested list from tabular data, then onward into a nested association. I can get part way with the help of this answer but it only works for the first level. Repeated use of this ...
273 views

### Partial fraction expansion with complex numbers

$$\text{Apart}\left[\frac{1}{x^4+1}\right]$$ Does nothing. How can I get it to expand it. Sometimes it is useful.
210 views

### How can I draw a box with moving particles inside and a hole in one side? [closed]

The idea is to create a simulation for ideal gas motion in a container that have a hole and then find the speed distribution for the gas particles that leave the box through the hole. I have a ...
104 views

### How to plot two random functions (Together)

I have ploted the next following jump diffusion model using Mathematica 10 $$X_t=X_0 e^{\sigma W_t+(v-\sigma /2)t}(1+J_1)\cdots(1+J_{N_t})$$ namely, a Geometric Brownian motion with compound Poisson ...
125 views

### NDSolve-Problem (Calculating field lines)

I want to calculate the field lines of a quite nasty vectorfield. In general the method works fine - except, one of the components of the VF gets 0 - then NDSolve ...
267 views

### Adds a rug representation to plot

This question came to me when I read How convert list of numbers to list of points on x-axis? @Mr.W suggested Interlacing a single number into a long list for the question. @Artes provides a very ...
92 views

### Replacing function in Sum

I have this expression, which, after execution, gives these $F[s,r]$ in output. $$S_{1,1}=\sum _{s=1}^{16} \sum _{r=1}^{16} F(s,r) \text{Tr}\left[G_r.G_1.G_s.G_1\right]$$ Here is a piece of ...
66 views

### Using Apply on a function with multidimensional input

I have a user defined function which takes multidimensional input, e.g a function that takes two algebraic variables a and b as well as a matrix m and computes some rule function as: ...
163 views

### Set PlotTheme globally?

Can one set a default PlotTheme globally? While I recognize one can make lots of workarounds to sort of do this: Go to ...
370 views

### Isometric perspective for Graphics3D

Is it possible to render Graphics3D in an isometric projection? I know that the ViewPoint option can be used for orthogonal ...
64 views

### Controlling the evaluation of other arguments in pure functions [duplicate]

I have a piece of code where I would like to do the something like the following: ...
117 views

### Three questions about two plots

I used the following code ...
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106 views

### Combine ListLinePlot and ListPlot3D using Graphics3D

I want to plot something very similar to what is plotted by @Sjoerd C. de Vries in Can 2D and 3D plots be combined so that the 2D plot is the bottom surface of the 3D plot boundary? I need to combine ...
223 views

### HDF5 importing large arrays

I have some computations that output a 300,000,000 element array of long unsigned ints, so about 2.4GB, in an h5 file. Mathematica handles files south of 2GB fine, albeit taking very long to import ...
156 views

### Mathematica error code 0x00000171

I'm getting above error code with a Trap 132 indication when attempting an ArrayPlot of a complex 130000 x 2048 matrix. Using Mathematica 9.0.1 with Mac OS 10.10.3 ...
134 views

### How to check keys and values in nested Associations?

Considering we have a an association: ...
223 views

### Is there any Mathematica functionality enabling its use for the blind?

A colleague of mine has become blind as the result of a sudden medical misfortune. We want to help him to feel useful and active again. We, however, still cannot determine what can be done and to what ...