8
votes
2answers
220 views

How can I create an object in NETLink from System.Collections.Generic.List

I am using NETLink and I am trying to construct the following .NET object List<string> list = new List<string>(); My first question is how can I load ...
10
votes
1answer
259 views

How to prevent simplification?

I have a question about the concept of simplification. I want to explain it with an example. When I write $4/8$ in mathematica, output is 1/2. How can I return ...
26
votes
3answers
2k views

Generating 250 random points crashes the kernel, but not 249

Fixed in 10.1.0. Consider the following function, which generates uniformly random points on the surface of the 2-sphere: ...
0
votes
1answer
67 views

Derivatives of overscript variables

If we have an expression with terms of some variable and terms of the same variable with some overscript, the differentiation of this expression does not entirely function. The problem is that ...
4
votes
3answers
451 views

Specific factoring of fourth degree polynomial

I have a pretty unspecific question about a really specific thing -- How would one use Mathematica to find values for an integer, m, such that this polynomial ...
3
votes
1answer
176 views

How to make a diagnostic plot for the regression?

Context I am interested in LinearModelFit, and would like to make diagnostic plots using Mathematica. I cannot find them in Mathematica document center. For example, the following R program makes ...
2
votes
0answers
137 views

Position from 3 dimensional acceleration data? [closed]

Per a previous post on Mathematica StackExchange here I'm trying to utilize 3-axis accelerometer data to determine approximate 3D position. I wanted to start with a simple case. To this end I've ...
-1
votes
1answer
154 views
5
votes
1answer
285 views

A problem about Steffensen method

Two days ago,I asked a question about bisection algorithm. Thanks for Michael E2 giving me a good solution My algorithm 1, I use the bisection algorithm to generate a initial value that contain a ...
2
votes
1answer
72 views

fields entry in ref/StreamPlot

In the ref/StreamPlot help file in Mathematica 10.0.2, we see the following image: Can someone explain how I would type this into an input cell?
1
vote
1answer
1k views

How to specify x axis values in the ListPlot[] [closed]

I am using ListPlot[] to plot a list of 1000 values. I need to specify the value shown in x-axis.It seems that is a classic question but I have looked for in this forum but I did not get any response ...
1
vote
2answers
188 views

Pattern Matching in Lists

I have a UN voting dataset – taken from a CSV file – where each row is in following format: ...
2
votes
2answers
425 views

The graph of inverse function $f^{-1}(y)$

Show that $f:I=(-1,1) \rightarrow \mathbb{R},$ it follows that $$ f(x)=\begin{cases} \quad1-x & \text{ as } -1<x\leq 0, \\ \frac{{x}^{-1}+ \lfloor {x}^{-1}\rfloor}{1+{x}^{-1}+\lfloor ...
3
votes
2answers
453 views

Plotting boundary of piecewise function in ContourPlot

I am trying to do a ContourPlot of the following function: ...
1
vote
1answer
160 views

What kind of PDF files that MMA does not read (import)

SORRY that I have tried 5 different files, which were too complicated for MMA to import. So I thought that maybe it just does not read any files. But I was wrong. So edited my question. In here, is a ...
8
votes
1answer
197 views

Is Mathematica's (v10.0.2) NetCDF exporter broken? [duplicate]

I'm trying something very simple, namely: Export["file.nc", {"Datasets" -> {"seqs" -> {"AAA", "BBB"}}}, "Rules"] And getting Java errors about "illegal ...
1
vote
2answers
153 views

Pattern Match and Replace Expression involving Pure Function

Let's say I have an expression that in held form contains a pointer to a function. expr = Hold[2*{"FUNCTION1"} + 5]; ...
1
vote
2answers
134 views

How to adjust the animation rate in a Manipulate environment

The enclosed code is a simplified version of the "Make Your Own Solar System" demonstration. How do I remove the manual Faster and Slower animation controls and add code for a permanent very slow ...
3
votes
2answers
257 views

Trying to Figure Out how to work with datasets & Classify[] and Predict[]

I'm new to Mathematica and I'm a bit overwhelmed. I have always used R for my statistics problems. Now that I'm trying to replicate what I do in R in Mathematica I'm making little progress. For ...
5
votes
3answers
372 views

Multiplying block matrices

I have a 2*8 matrix A, and a 2*8*2 matrix B. So B[[1]] and B[[2]] are both 8*2 matrices. I need a neat way to multiply A by B so that the first list in the result is A.B[[1]] and the second list ...
4
votes
1answer
225 views

Regular Polyhedra coordinate points generation

Is it possible to get all points on a Polyhedron surface using two surface parameters, say $ \phi,\theta $ spherical co-ordinates? Just like in ParametricPlot3D, ...
5
votes
2answers
330 views

Integration of a Rational Function returns RootSum[]

I am trying to solve an integral given below: Integrate[r^2/(-α r^3 + r^2 - 2 m r + Q^2), r] but since coefficients of this cubic polynomial are as parameters, ...
-1
votes
2answers
184 views
2
votes
1answer
75 views

Partitioning a list in n sublists with constrains in their sums

Is there a way to put cluster level limits on clusters? For example, if I run: FindClusters[{1, 2, 3, 4, 4, 6, 7, 10}] I get back two lists, ...
10
votes
1answer
626 views

Moving polygon on path curve to create 3D shape

How can I move some polygon list = {{0, 0}, {0, 15}, {7, 13}, {2, 13}, {2, 5}, {5, 5}, {5, 3}, {2,3}, {2, 0}}; Graphics[{Black, Polygon[list]}] so it follow some ...
4
votes
1answer
221 views

Test for group isomorphism and construct automorphism groups

MMA has some support for group theory, allowing representation of any finite group as a subgroup of $S_n$. It does not seem to have a function for testing whether two finite groups are isomorphic. Is ...
2
votes
0answers
86 views

Font rendering difference between .jpg & .pdf [duplicate]

I have some planar graphics involving lines and text, produced by Line[] and Text[], accepting the default font on the latter. ...
2
votes
2answers
112 views

Using `Fold` to show stages of Euler product formula

I would like to recursively replicate each stage of the Euler product proof. This does it: ...
7
votes
3answers
449 views

How to prevent instability blow up in NDSolve?

I have the following code to solve a PDE: ...
2
votes
0answers
204 views

Visualizing the Gradient Vector

I already found this Example but i want to add a description and the individual vectors as in the picture. My approach so far: ...
12
votes
8answers
598 views

Find the minimum integer r such that $(10^r - 1)/37$ is an integer

I know Element[(10^r - 1)/37, Integers] tests the condition. So what is the command that gives me the minimum integer value r ...
0
votes
1answer
363 views

Issue with integration from 0 to infinity with constants [closed]

I am trying to take the integration for $\int_0^{+\infty}e^{-\alpha t}sin(\beta t)d t$. Here is a screen shot of what I did: The solution to this integeation should be ...
0
votes
0answers
113 views

Simplify BeginPackage with Package of Packages

I have a group of Packages that I use to create a lot of other Packages. Let's see an example: ...
2
votes
3answers
319 views

Picking items from a list

There's probably a Mathematica primitive to do this, but I don't know what it is...suppose I wanted to construct a list of all integers from $1$ to $n$ that were not divisible by $12$, and that were ...
2
votes
1answer
43 views

Default value behaves differently when used in Function and when used with Cases

Consider this example: Cases[{4, x, 5 a , 6 x}, x_.*a_ :> x] (*{1, 1, 5, 6}*) It is clear that the _. took 1 as a ...
1
vote
1answer
204 views

Input of ions and compounds in Wolfram's Mathematica [closed]

I want to use Wolfram's Mathematica to see some data about certain ions. I don't know how to write the chemical's compounds or ions full names, so that at this time I need to write its "formula". ...
0
votes
0answers
327 views

Issue in NDSolve and unknown error

I try to solve a simple BVP: $A {v}''(t)+B v(t)=f(t)$ where $A, B$ — $5\times 5$ matrices, $f(t)$ — 5-dimentional vector-function with the use of NDSolve. Each component of $f(t)$ is a combination ...
2
votes
0answers
183 views

DSolve versus DSolveValue [closed]

I've just discovered the new command DSolveValue in Mathematica 10. Is this new command now the preferred instead of DSolve? Is it the better command to teach to students? Same question for ...
3
votes
1answer
272 views

Rescaling and reorienting Matrix Plot axes

I have implemented a numeric Laplace Solver in C++ and am trying to graphically represent the validity of my method. I have outputted the grid from C++ and imported it into Mathematica to get the ...
2
votes
1answer
191 views

Manipulate: ListPlot and Labeling

I am trying to make a set of scatterplots where the 'u' value is a year. I am using the following dataset: ...
2
votes
1answer
105 views

PrimitiveRoot function

The function PrimitiveRoot[n] claims to return the smallest primitive root of n. I believe this is not true. For example ...
3
votes
3answers
201 views

How to Update 2D List based on a binary array

I have 3 lists: numbers = {{1, 2}, {3, 4}, {5, 6}}; toUpdate = {{1, 0}, {0, 0}, {1, 1}}; newValues = {{10, 20}, {30, 40}, {50,60}}; I have to update the list ...
11
votes
2answers
728 views

Rendering thousands of points

I am trying to render an image with some 120,000 Points. Technically it's just 10,000 points, plus their reflection, plus 5 rotations of both of those sets, but I'm ...
9
votes
3answers
947 views

Implement the Bisection algorithm elegantly and easily

Description: Rencently, I have finished my course Numerical Analysis, so I'd like to implement many algorithm that I have learned from that course.By this practice, I hope that I can improve my ...
1
vote
1answer
43 views

hold specific pattern in symbolic calculation

I encounter some questions when I try to simplify a symbolic expression using Mathematica. For example, I got an intermediate expression ...
0
votes
1answer
248 views

RegionPlot of an area inside a polar plot (or its equivalent parametric plot)

Let' s take a most simple example for a polar plot, the Archimede's spiral. ...
2
votes
2answers
82 views

Association without an associated value

Sometimes, we only need to store the keys which will be checked whether certain keys exist in the data structure(corresponding data structures in C++ are std::set ...
1
vote
3answers
170 views

Create a function which gets a function and a x as argument and returns the y [closed]

After a few hours and lots of tries, I am hoping that someone could give me a solution to my problem. I want to have a function, which gets a function and a value as arguments. The function should now ...
2
votes
1answer
76 views

Finding if a graph contains an even cycle

I am looking for a simple boolean-like function which could check if a graph contains an even cycle. I'm aware there is ExtractCycles but I'm looking for a true/false output than a list of cycles.

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