# All Questions

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 ...
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}} : ...
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### 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 ...
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 ...
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 ...
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}, ...
162 views

### Probablity weighted ReplaceAll

I'm looking for an elegant way of doing a probability weighted replacement rule, something like this ...
342 views

### Given f[1] … f[k], k = 1, 2, 3… how do one find the general function f[n]?

If I have that ...
125 views

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

### Backslash commands in strings?

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

### Is there a faster way to Map an Association?

Consider mapping an existing Association in a manner such as this: ...
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 ...
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 ...
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, ...
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 ...
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: ...
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 ...
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 ...
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 ...
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 ...
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 ...
307 views

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

I am trying to use ListVectorPlot in combination with WeatherData and CountryData to show ...
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 ...
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 ...
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 ...
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 ...
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 ...
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 $m\times n$ ...
127 views

### eccentric anomaly expansion equation

I try to use this simple algorithm (paper) to calculate the Eccentric Anomaly expansion: ...
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 ...
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: ...
169 views

### TrueQ returning False on true statement

Why does TrueQ return False on the following? TrueQ[Log[2]/Log[8] == 1/3] (* False *) ...
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: ...
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 ...
371 views

### How can I mend this broken heart?

Try to evaluate the following code: ...
293 views

### How to slice TimeSeries data?

When retrieving curated data, v10 now returns TimeSeries objects. For example, ...
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 ...
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 ...
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, ...
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, ...
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 ...