# All Questions

83 views

### Solving a complicated system

Could anybody please make a suggestion how can I implement this program which attempts to solve $2$ dimensional complex system of equations? My computer is not able to solve... After 3 hours the ...
46 views

### how can I manage the characters encoding of retun value from FetchURLWithHeaders?

I have retrieved a file from a web server by means of the FetchURLWithHeaders function. The retun value from FetchURLWithHeaders should contains the substring SCHØNHEYDER but instead I find ...
50 views

### How to query W|A, to get a list of asymmetric, bicubic and $3$-edge colorable graphs? [closed]

I'm interested in finding graphs with certain properties, like the smallest cubic bipartite asymmetric graph. While working on a related graph-theoretic problem, concerning edge-colrings, I came along ...
192 views

### Why can AppendTo modify a referenced list in-place but Part cannot?

Part, AppendTo, PrependTo, AddTo, etc. allow in-place modification of a list, but only Part requires that the list be referenced through a simple symbol, e.g. the following all does what you'ld ...
93 views

### How to obtain numerical answer for equation containing integration

Could some one tell me how to obtain numerical value of $a$ and $b$ from equations below: $$\frac{1+exp(b)}{1+exp(0.9a+b)}=0.95$$ $$\int_{0}^{\infty} \frac{1+exp(b)}{1+exp(a x+b)}=1$$
109 views

### Mean Preserving PDF Spreading

I have a histogram representing the PDF (probability density function) of an unknown discrete RV. The histogram is asymmetrical. Is there a known way in Mathematica to increase/decrease the variance ...
32 views

### Testing for a vector of all reals [duplicate]

I want to test if an expression is a vector of all reals. I defined RealVector[expr_]:=VectorQ[expr,NumberQ[#]&&(Head[#]===Real)]; Trying this on ...
456 views

### Finding all sublists or substrings of a given list/string

Given a list or string, how do I get a list of all (contiguous) sublists/substrings? The order is not important. Example for lists: ...
51 views

### Retrieve Options from function other than graphics objects

We can retrieve information about used Options for Graphics via: Options[Plot[Sin[x], {x, 0, 1}], "AspectRatio"] (* {AspectRatio -> 1/GoldenRatio} *) even if ...
121 views

### calculate missing values, Interpolation

I've following data: ...
123 views

### How to make $a1**a2** \cdots **an=0$ for a given $n$?

In order to optimize my computation and save memory, I'd like to modify NonCommutativeMultiply so that for a given $n$ one has $a1**a2** \cdots **an=0$ for any $a1, a2, \ldots, an$. To make it ...
178 views

### Localising OptionValues

The documentation on OptionsPattern leaves me with some unanswered questions. From the example section: ...
146 views

### How to properly apply NumericQ or s.th. similar here? - NDSolve inside NMaximize

I wrote a function that numerically solves a given Schrodinger equation and returns replacement rules to obtain the time evolution operator. It looks and is used as follows: ...
67 views

### How to put a fixed sized frame around traditional form expression

The height of a 2D form of a polynomial changes depending on the existence of exponents, fractional coefficients, etc. For use inside a Manipulate, I would like to ...
285 views

### Equivalent of Matlab's uigetfile in Mathematica

I was wondering if there an equivalent of the "uigetfile" Matlab function to use it in Mathematica. To be more precise, I want to read many Excel files and I don't want to type a static path; ...
97 views

### Testing for a vector of reals [closed]

Suppose I define: RealVector[expr_]:=VectorQ[expr,NumberQ[#]&&Head[#]===Real)]; Then: ...
127 views

### User Input Through Dynamic

For my application, I am using Dynamic functionality to make a number of input fields through which a user can enter numbers. I then take these numbers and place them as the entries in a dynamic ...
209 views

### accessing elements of nested list

I have a list of the form: toy = {{a, {b, c}}, {d, {e, f}}, {g, {h, j}}, {k, {m, n}}}; and would like to create the list ...
106 views

### Finding x when sin(x) = -.758 [closed]

I'm not understanding how to find all the angles for when sin(x) is equated to a negative decimal can someone explain to me how to find it..? So far I came up with 49.288 degrees, and 229.288 degree. ...
240 views

### Inconsistent image sizing with Grid and Row?

Can anyone explain why Row and Grid don't size the image correctly and consistently to 300 ...
465 views

### How to create a Disk with smoothly changing coloring?

I want to have a disk. But this disk shouldn't have a fixed color; instead, I'd like it's color to fade smoothly. Until now, I came up with two ideas how to achieve this. Idea #1: ...
145 views

### How to sample only odd numbers in the domain of a table for list plot [closed]

The following code samples $k$ points around a circle at integer values starting from $0$: ListPlot[Table[{2 Sin[(2*y/x)*π*n] , 2 Cos[(2*y/x)*π*n}], {n, 0, k}] I ...
59 views

### How to Fold (FoldList) this in a more compact (efficient) way?

Example code: x = Table[something[i], {i, 5}] Table[Fold[f1[#1, f2[#2, a], a] &, x[[i]], {c1, c2, c3}], {i, Length[x]}] This above is just an example. I ...
145 views

### Incorrect use of Scaled causes crash

Bug introduced in 8.0 and fixed in 10.1.0 While playing with Scaled, I made a syntax error which caused a crash instead of an error message ... Do you get the ...
95 views

71 views

### Getting a remote kernel from a machine not directly reachable

I have a machine capable of running Mathematica on 24 cores which I would like to take advantage of :) The only problem is that this is a remote machine to which I cannot connect directly, I have to ...
97 views

### TensorReduce not simplifying transpose for symmetric matrix?

I know Mathematica is not very good with symbolic manipulation of matrix expressions, but I was surprised to find that it can't reduce the following expression: ...
153 views

### NDSolve is running an extremely long time: how can I save the existing data?

I am trying to solve a PDE by the following code. It takes 1 hour or so to reach t=25.72 but about 20 hours to reach t=25.72404031638060174049337306126853310997. Actually, the time step is extremely ...
102 views

### Getting a part of a matrix Inverse for later use

I was trying to get an element of a matrix, and use in further computation of my program. Problem was that its not reading the value unless and until I specify it again. My code is: ...
349 views

### How do I show only the intrinsic color of 3D polygons?

System: Mathematica 9, Windows 7. I want to assign a polygon a color in such a way that it is rendered in that color irrespective of any ambient light sources. In other words I want Yellow to be ...
133 views

### Mathematica GUIKit

Does anyone of you know if the GUIKit package is still under some development by Wolfram Research or is the current version 1.1.0 the last one. Does it make sense to make GUIs using this package in ...
193 views

### How to make hollow Graphics3D?

I keep seeing a notebook to use of Mathematica as a 3D Printing tool (e.g.: this link). In the notebook on slide 8/11, we find these pictures: I'd like to design it as such that, but I don't ...
216 views

### How to filter a dataset using Select and a parameter

I'd like to filter a Dataset using a parameter in Select, but so far I haven't been able to make it work properly. Say that I ...
117 views

### I am trying to solve a set of coupled differential equations with known boundary conditions using mathematica [duplicate]

Here are my differential equations and boundary condition. ...
68 views

### Brevity of denoting Conjugate[]

How do I make Conjugate[] expressions have a bar above them instead of Conjugate[ before them, in order to shorted up expressions? I'm looking at something like this screenshot for example:
204 views

### Understanding SameQ

I am new to Mathematica. So I have read the documentation for comparing expressions in Mathematica and I still don't get the SameQ (===) function. Let me give you a short example: ...
327 views

### Long list of similar rules

Given the following: ...
108 views

### Random generation of three-non-collinear and four-non-coplanar points in 3D space

Please, take a look to this code. How it can be improved so that the time execution becomes smaller? ...
68 views

### Generating a Variable Number of Dynamic Variables

I know questions that get at this very issue have been posed in other ways here, but as a relative beginner, I've had trouble understanding the answers. For my application, I am developing a simple ...
148 views

### What's real analogue for FromDigits?

FromDigits only works for integer strings. What's its real-number analogue?
53 views

### Variables within functions within DSolve

Hi I am just beginning to learn Mathematica and this is my first time I have been exposed to any type of coding. I am encountering a problem in a basic physics problem. For example we are always ...