3
votes
2answers
159 views

Retrieving other information on CountryData

The following input will produce some answers, however how do we find out other details, such as the specific year the result corresponds to, as well as the source from which the data is obtained? ...
5
votes
2answers
239 views

Table with multiple iterators running parallel

I want to use Table to generate a list, but it only allows one iterator to increment at a time. So in ...
0
votes
2answers
50 views

Multiply value if it includes a period

I download data from an online source, now I have a problem: the source code doesn't allow to differ between values of 10 (which actually stands for 10) and 10.000 (which is 10'000, but Mathematica ...
5
votes
1answer
380 views
3
votes
3answers
178 views

Multivariate Polynomial Manipulation

I have a large homogenous multivariate polynomial in, say, 5 variables $a,b,c,d,e$. As an example take the polynomial $$a^4+2abcd+a^2 b^2+e^4+cde^2.$$ Now I would like to replace $k$-th power of any ...
3
votes
0answers
68 views

Error solving third order ODE in version 10. No error in V9. DSolve`DSolveKovacicDump`

This is an ode which is solved with no error in V9, but gives a very strange error in V10. Is this a regression bug? On version 9, the ode is solved with no error ...
3
votes
5answers
242 views

Take the next element in a nested list

My problem is the following: Consider a list of elements. To better understanding my following explanations, I would take this example: ...
3
votes
1answer
198 views

Use of Ito's lemma in ItoProcess

In the documentation for the ItoProcess it says: Converting an ItoProcess to standard form automatically makes use of ...
9
votes
1answer
265 views

Connect Frontend to Kernel Started by JVM via JLink

I have a MathKernel started and controlled via JLink from a JVM. The $CommandLine for this kernel is: ...
10
votes
2answers
219 views

Evaluate selection in new window or new notebook?

Sometimes when you have long code you need to check some part of this code. the way I am using currently is to selected the part that I want and then copy it to new notebook and then evaluate it ...
4
votes
4answers
312 views

Automatically growing lists as in MATLAB?

Is there a way to add elements to a list at positions outside the current list's length? Something equivalent to the following MATLAB code snippet: ...
7
votes
1answer
291 views

Porting code from MATLAB

I'd like to switch from MATLAB to Mathematica for my research in digital signal processing. I used Mathematica a lot during the '90s but I haven't used it since then, so I might as well be a complete ...
4
votes
3answers
316 views

How to solve an integral equation by iteration method? [duplicate]

How I can obtain $n^{th}$ approximation of the following equation $f(t)=t+\int_0^tds f(s)$ by iteration method?
4
votes
1answer
165 views

How to input and output partitioned matrices that show partitions and compute as normal?

I want to demonstrate multiplication of partitioned matrices as in the example here. Using the Insert Menu, you can build a matrix and draw lines between rows and columns. However, I want to be able ...
1
vote
0answers
140 views

Solving PDEs with complicated boundary conditions

The system I'm trying to solve is $$\nabla^2 C_{(r,\theta)} =0$$ $$C_{(\infty,\theta)}=C_0$$ $$ [ \frac{\partial C_{(r,\theta)}}{\partial r} \cos(\theta)+\frac{1}{r}\frac{\partial ...
0
votes
3answers
145 views

List of Coefficients of Expression with symbolic Terms

(I am affraid that this is a duplicate, but I read several already asked questions and non of them helped me. If it's already answered, please tell me) I have expressions like this ...
2
votes
0answers
131 views

Mathlink program with low cpu usage on linux machines only

Question I am incorporating some c++ code via Mathlink into my simulations in Mathematica. My questions involves the execution efficiency of the c++ code on different machines. For example, on my ...
2
votes
1answer
88 views

ZTest result not making sense

I'm using version 10. I'm having difficulty with understanding why I'm getting some output from the ZTest function. Here is the code for my specific example. ...
0
votes
2answers
62 views

Eigenvectors inside a maniupulate function

I am trying to make a physics application and it requires that the eigenvectors be taken for a 3x3 matrix. It is my intention that Mathematica never have to deal with the matrices symbolically. ...
2
votes
1answer
91 views

How to efficiently process pasted content from PDF

I had selected a matrix in a PDF file, and paste it onto my MMA notebook. Below is the exact copy-pasted content: ...
3
votes
1answer
188 views

Cellular Automata Neighborhood as Node connections

Can I use the CellularAutomation[] function where the neighborhood is defined by the connections between nodes? For example, if 1 -> 2, 1 -> 3, 1 -> 8, 1 ->1, then the neighborhood of node 1 is the ...
0
votes
0answers
84 views

How can I scale a plot in my Manipulate?

I want use scale in the same way as Mister Trevor Cole in his most excellent demonstration at the Wolfram Demonstrations site: ...
3
votes
1answer
96 views
2
votes
0answers
303 views

Is there a way to use video codecs for avi files in Mathematica?

I would like to use Mathematica to create compressed .avi video files from image sequences. I read the documentation on .avi but couldn't find a solution. In the documentation it says: ...
2
votes
2answers
84 views

Why isn't Refresh working as expected? [duplicate]

This seems to me to be a very easy question, but I can't seem to figure it out. Instead of updating every 1 second, it auto-updates as quickly as possible. ...
4
votes
1answer
92 views

How to create a CDF “on the fly”?

I don't know if I have asked the question the right way: As CDF is essentially a simple text file, I would like to create it "on the fly" without saving it to the hard drive. I would like to give a ...
1
vote
1answer
66 views

A code deal with Lists operation ---Needs optimizion

I have written some code to deal with lists, But the speed of the code is slow, Could Someone help me to speed up it? Probably could rewrite it with Functional Programming! Give me some ideas! The ...
2
votes
0answers
43 views

Custom WindowToolbar for my stylesheet

So I've noticed that some stylesheets (for instance Slideshow stylesheets) load a toolbar using the assignment WindowToolbars -> {"ToolbarName"} and I've been ...
1
vote
0answers
153 views

Numerically solving a 2D oscillating integral

I'm having trouble solving this integral numerically: ...
3
votes
1answer
309 views

how to create Dataset after importing txt file

I would like to translate a imported txt file to Dataset. ...
2
votes
1answer
116 views

Is there a hotkey for the drop down selection/information?

I am more used to typing then using the mouse. I was wondering if there were hotkeys for the drop down list and the info button? What I mean is what I have marked in the picture below. When I ...
2
votes
1answer
110 views

Setting a Row from a Matrix as Variable

I'm not advanced in Mathematica but I'm trying to get better. I have a big set of Data and I want to Plot the first row against ...
7
votes
1answer
148 views

How to convert \[Formal…] symbols to standard ones in an expression?

Mathematica generates an expression sometimes using \[Formal] symbols. This is causing a problem with the TeXForm code generated ...
26
votes
3answers
1k views

Symbolic solution(s) to generalized Heat equation

Symbolic solution(s) to Heat equation? or more generally,(eventually) Green functions to known PDEs I am interested in variations of the heat equation: or more generally or even more generally ...
2
votes
0answers
68 views

DSolve breaks when the ordering of independent variables aren't proper?

I encountered this when trying to solve this problem with DSolve: ...
4
votes
1answer
185 views

Get the last line from each of a large number of files, transform them, and write all results to a single new file

I have several hundreds of .csv files that are not logically named (contains numbers, characters, and special characters), all stored in a directory. Each file has large but unequal number of rows and ...
14
votes
2answers
431 views

Where can I get detailed information on how the Plot command works?

The command Plot[x^2, {x, -3, 3}, PlotStyle -> Arrowheads[{-.025, .025}]] /.Line -> Arrow produces this output. What I don't understand is what ...
1
vote
1answer
131 views
2
votes
2answers
73 views

Order of Evaluate for Map

I would like to get a list of variable names as strings. For example, x = 1; y = 2; Map[SymbolName, Unevaluated /@ Unevaluated@{x, y}] {"x", "y"} This works ...
1
vote
1answer
163 views

Use NDSolve to solve a PDE

I have the following PDE (a master equation, and $P$ is probability density, $0\le x\le1$ and $0\le y\le1$): $$ \partial_t P(x,y,t)=x\partial_xP(x,y,t)+(1-y)\partial_yP(x,y,t)+2P(x,y,t) $$ The ...
2
votes
1answer
100 views

What is the correct way to plot a dynamically generated list of functions?

For example, I want to generate a list of random waves and plot them. Then I wrote f:=Random[Real] h:=Floor[f*20] And then ...
14
votes
1answer
372 views

MatchQ-ing Associations (MMA 10)

Consider {x->1} which has FullForm List[Rule[x, 1]] and, therefore, ...
1
vote
3answers
57 views

Collect the lists

I have a list of lists from which I pick out the positions of the number 1 and then print out these positions for each list. I am having some trouble collecting what I am printing into a list / matrix ...
0
votes
0answers
32 views

Generating a Table with a certian Density [duplicate]

How do I create a random table of 0's and 1's with a certain density instead of a probability? For Example: Manipulate[ Table[RandomChoice[{1 - density, density} -> {0, 1}, {10}]], ...
9
votes
3answers
555 views

Converting datasets to nested lists

Imagine the Shipments relation: ...
15
votes
4answers
618 views

HoldForm doesn't hold form

Bug introduced in 10.0.0 and fixed in 10.0.1 In Mathematica version 10, HoldForm no longer produces the same results as in version 8 (edit: I only have versions ...
2
votes
1answer
162 views

Mathematica unable to solve equation numerically while Wolfram|Alpha can

I want to solve the following equation 2 x == Sinh[x] Mathematica is unable to do so ...
0
votes
0answers
296 views

Stochastic Simulation using the Gillespie algorithm

I'm trying to reproduce the simulation with demographic stochasticity in Figure 1 from the paper entitled "Dynamical Resonance Can Account For Seasonality of Influenza Epidemics" ...
5
votes
3answers
483 views

How to measure cross sectional area of Tube

I have modified my question to a simple version. I have vertex clusters, polygons and a list of center points. Attached pts and polygons of 3d tube are: ...
29
votes
3answers
909 views

Changing Values in an Association using Map

I am trying to change the value of one key in an association based on the value of another key in that association. So if my association starts as: ...

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