11
votes
0answers
352 views

Learning Resources for Data Science in the Wolfram Language

I'm delivering an upcoming course on Data Science with the programming/analysis done predominantly in the Wolfram Language. I created the following table to leverage students' familiarity with Lists ...
0
votes
1answer
60 views

Why can NSolve only solve this system of equations after trivial substitution?

The first system immediately yields {}, but the second, equivalent, system yields the solution {{k -> 4.96048, tl1 -> 1.64842, tl2 -> 2.07466}} : ...
0
votes
0answers
33 views

What is that Root[…] inside the answer represent? [duplicate]

So I am encountering this situation, in which mathematica doesn't give me the answer, but in a form of "Root". How do I interpret this ? what is the number after the "&" represent? How should I ...
3
votes
0answers
169 views

Undirected Network and its Monte Carlo Simulation

So I have this array of points, in the form {x, {y,z}}, where x is the node number assigned when I used the locator pane to make a network, and y and z are its unitary coordinates. The graph is made ...
3
votes
1answer
136 views

Interpolation function rejected by ParametricPlot3D

I was playing around with the bouncing ball example, and decided to make a 3d version. I decided to use ParametricPlot3D for a simple independent 3D ...
2
votes
0answers
103 views

How to handle infeasible points in FindRoot?

I am calling FindRoot[f[x,y],{{x,xInit,xMin,xMax},{y,yInit,yMin,yMax}}] where for some points {x,y}, ...
7
votes
2answers
162 views

Probablity weighted ReplaceAll

I'm looking for an elegant way of doing a probability weighted replacement rule, something like this ...
5
votes
2answers
342 views
1
vote
1answer
125 views

why head Association cannot be replaced by head List [duplicate]

Consider replacing head of List by head Association: {a -> x, b -> y, c -> z} /. List -> Association (*<|a -> x, b -> y, c -> z|>*) ...
4
votes
1answer
127 views

Operator-Input Form for Lists?

The documentation on Operator-Input Forms shows the following example which suggests that there is an alternative, convenient, operator-style, tidy technique for inputting lists. However, there is ...
6
votes
3answers
606 views

Can NDSolve handle discountinuos data?

It is possible to numerically solve a differential equation if not-smooth data are involved? For example the following instruction return the error NDSolve::bvdisc: ...
9
votes
2answers
186 views

Backslash commands in strings?

I discovered by playing around that Text[DisplayForm@SubscriptBox["\[Lambda]", "k"]] produces the same result as ...
7
votes
1answer
243 views

Is there a faster way to Map an Association?

Consider mapping an existing Association in a manner such as this: ...
1
vote
1answer
48 views

Automatic substitution of fractions

I have several equations with many variables, and here and there I would like to do a variable substitution. For example, in the equation: a (b + 42 c / d) I ...
8
votes
2answers
148 views

Which function definition is used to evaluate an expression that matches the lefthand side of more than one definition?

In a case like this: f[a_] := a; f[{a_, b_}] := a; I'm wondering whether I should expect f[{2, 3}] to return ...
10
votes
2answers
307 views

Testing Credit Usage in Wolfram Programming Cloud

I currently have a free WPC account, which I am using for testing purposes. Amongst other things, I want to find out more about how the credit system works, in particular how many credits are used, ...
2
votes
0answers
51 views

Unique CellID in-between notebooks

Documentation says that CellID is guaranteed to be unique for a given notebook. I've noticed that CellID are fairly high numbers and although probabilistically speaking the odds of coincidence are ...
2
votes
1answer
106 views

Black line after ImageTrim

as shown in Image correlation I would like to detect the shift between a stack of images. Here are the images: and here the code: ...
2
votes
2answers
460 views

How do I exclude the vertical line plotted at a discontinuity?

Condsider function = Tan[1 x] + Tan[2 x] Plot[function, {x, 0, 1.5}] It has a strong discontinuity around 0.8. The problem is , if I want to find ...
3
votes
1answer
114 views

How do I plot a U- form cylinder

I'm really new to Mathematica, trying to learn some things, but I need help trying to plot this kind of cylinder, a U tube like cylinder. Tried to use an example code like this, and then vary some ...
8
votes
1answer
128 views

How to get a list of all expressions in a notebook matching a certain pattern?

Suppose I have a Mathematica notebook saved to a certain location on disk. Given a pattern I need to get the list of all expressions matching this pattern that appear in input, output or print cells ...
0
votes
0answers
145 views

Improving the speed of evaluating Table with nested functions

I am a Mathematica novice working with a stack of 1024 x 1024 WatershedComponents (or MorphologicalComponents) label matrices ...
2
votes
2answers
82 views

Inconsistency of output format in `Eigenvalue`

I am bothered by the output format of the last two elements of efre. Is there a way to make these two look like the same format as the first two in ...
8
votes
3answers
307 views

“NotAvailable” and “NotApplicable” data points returned by WeatherData[]

I am trying to use ListVectorPlot in combination with WeatherData and CountryData to show ...
5
votes
5answers
322 views

Providing a color function for ListPointPlot3D

Is there a way to write ListPointPlot3D expression, so when given a list of points, the the color of the points plotted is a function of the index/element number of ...
2
votes
1answer
405 views

Converting a nested for loop from MATLAB

In MATLAB I have the following series of nested for loops that update a matrix. (It's not my code, but someone else's that I'm trying to replicate - I don't know ...
10
votes
2answers
335 views

Deploying to the Cloud for Public Access

Note: Fixed sometime around the 18th of August 2014. Bug present from the release of 10.0.0. until then. I wanted to test how a simple deployed program would appear to a non-mathematica user. I ...
1
vote
1answer
71 views

Conditions in SparseArray

I got confused by {i_, j_} /; in the following code. I didn't see an explanation in the SparseArray documentation. Can anyone ...
3
votes
1answer
298 views

Calculate geo location based on distance from other locations

Given a list of entities (or GeoPositions) and their distances from a particular location, how do I find that location's ...
8
votes
4answers
434 views

Fast method to select matrix elements based on a vector of positions

There is an operation for which I have long wanted to find a better solution. Let: a be a matrix of dimensions $m\times n$ ...
1
vote
2answers
127 views

eccentric anomaly expansion equation

I try to use this simple algorithm (paper) to calculate the Eccentric Anomaly expansion: ...
7
votes
0answers
220 views

Partial Differential Equation in Parallel

is there any native way to implement multi-core parallel solving of PDE in Wolfram Mathematica? WM 10 now supports Finite Elements Method, but it is actually useless without parallelization. Usually ...
3
votes
3answers
204 views

Zero-order interpolation not going fully around

Connected to this question, I want to do a zero-order interpolation of a bunch of datapoints which is periodic. The code I use is as follows: ...
3
votes
2answers
169 views

TrueQ returning False on true statement

Why does TrueQ return False on the following? TrueQ[Log[2]/Log[8] == 1/3] (* False *) ...
0
votes
0answers
42 views

How to correctly use PatternTest (?) [duplicate]

This works fine: {3, -5, 2, 7, -6, 3} /. x_ /; x < 0 :> 0 (*{3, 0, 2, 7, 0, 3}*) and this works fine: ...
2
votes
2answers
112 views

Utility information using FindGeoLocation in Ver.10

It is possible for some commuters to track the location of their bus, train or tram through a personalised GPS tracking device (e.g.see ...
17
votes
1answer
371 views

How can I mend this broken heart?

Try to evaluate the following code: ...
8
votes
1answer
293 views

How to slice TimeSeries data?

When retrieving curated data, v10 now returns TimeSeries objects. For example, ...
12
votes
1answer
290 views

Geographic background containing both outlines and contours: how?

I would like to create a map which will show lakes and rivers together with elevation contours and contour labels. What is the simplest way to do this with ...
4
votes
1answer
173 views

how to write TableForm expression into file?

Now I have a list stored in data as follows data = {{"Ca", 1, 1, 1}, {"Ca", 2, 2, 2}, {"Ca", 3, 3, 3}} the ...
0
votes
0answers
132 views

Finding Roots of Non-linear Systems: Rescaling polynomials

I'm trying to get all isolated finite equilibria of a moderate multi-dimensional non-linear system of equations. Particularly I have 9 independent variables and third order at most. It turns out that, ...
2
votes
0answers
44 views

How to avoid joining MathieuCharacteristicA in a plot? [duplicate]

In the documentation As a function of the first argument, MathieuCharacteristicA is a piecewise continuous function So how to avoid joining different pieces of the function? For example, ...
0
votes
0answers
149 views

NSolve for large models

I'm a Mathematica rookie running version 7.0 for Mac OS X x86 (64-bit) (February 19, 2009) on a 2010 MacBook Pro. (I'm also a stackexchange "newbie" who originally posted this on stackoverflow, thus ...
0
votes
0answers
55 views

Ordering oscillators with negative powers: Infinite loops

I have been working with ordering of oscillators for example $[a,a^\dagger]=1$ and I have a fairly stable code. I have needed to use inverse oscillators for example expressions like $a^m ...
0
votes
2answers
94 views

Changing the data indices for a large dataset plotted with ContourPlot

I have a large (square) dataset that I am plotting with ListContourPlot ... The data is 128x128 -- without coordinates for each point. I.e. - {{0,0,1,0,...,0},{0,2,1,1,...,1},...{3,1,1,1,...,2}} So ...
0
votes
0answers
51 views

Asymptotic expansion on 3 nonlinear ordinary differential equations

The 3 nonlinear differential equations are as follows \begin{equation} \epsilon \frac{dc}{dt}=\alpha I + \ c (-K_F - K_D-K_N s-K_P(1-q)), \nonumber \end{equation} \begin{equation} \frac{ds}{dt}= ...
11
votes
2answers
256 views

Sqrt disappeared when exporting plot to PDF in version 10

Bug introduced in 10.0.0 and fixed in 10.1.0 In version 10, if we plot with Sqrt in y-axis, and export to PDF, the square root disappears in the PDF file. ...
3
votes
1answer
119 views

NDSolve: EventAction list specification using Table fails

I have an NDSolve problem that needs a list of a large number of events that are generated programmatically. Here is a simple example that demonstrates the problem on Mathematica 7 and 8 (the versions ...
2
votes
3answers
293 views

Create a list of random reals

How can I create a list of random pairs $(x,y)$ where $0<y<x<1$ and $x,y \in \mathbb{R}$ ? I can't seem to place that inequality restriction on the random numbers that are generated.
8
votes
1answer
165 views

One ChartLegend for multiple charts in Dataset?

Dataset's documentation shows how to leverage GroupBy operator at multiple levels ...

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