# All Questions

105 views

### Mysterious behaviour of Plot

I'm a little mystified as to the behaviour of Plot. In one case below I am directly executing on a list element. In the other I am (I think) doing exactly the same thing. ...
153 views

### How do you make a 3D city population graphic?

I want to make a graphic that has the shape of a country, finds all the cities of that country, gets their coordinates and populations and turns that into a SmoothHistogram3D with the population being ...
107 views

### CDF plugin no longer launches in Chrome

I exported a web-embeddable CDF, and created an html page with the automatically generated code. Both are in a local folder. When I open the HTML page in a Chrome browser, i get the PNG image telling ...
45 views

### Two installations of MMA 10.0.1.0 differ in behavior

I'm seeking advice on how to track down what might cause the following difference in behavior. I have two independent installations of MMA 10.0.1.0, both on Mac OS X Mavericks on identical x86 Mac ...
38 views

### VertexConnectivity and FindVertexCut disagree [duplicate]

I'm trying to use Mathematica to compute the minimal vertex cut for graphs. From what I understood, VertexConnectivity of a graph should correspond to the number of vertices in the minimal vertex cut. ...
19 views

### NIntegrate is it possible to evaluate the integral using a user-defined grid?

I am using the NIntegrate function and I would like Mathematica to perform the integration in accordance with a grid I define that is sampled uniformly between the boundaries of integration. Let me ...
44 views

### How to make a LogLinearPlot out of an Histogram?

I want to make a histogram with a logarithmic x-axis, like the one produced by LogLinearPlot. How can I do this?
54 views

### How do you get a country's GDP per capita in Euros?

Right now, I'm getting the data in U.S. Dollars and converting it to Euros like this: ...
46 views

### Optimiazation method L-BFGS-B

I am comparing a result of optimization using R and Mathematica. Mathematica (NMaximize) has found a significantly better (global optimum) result then R (using ...
63 views

### Conversion of Sine to Cosine

I'm solving equations with many Cosines and Sines. And I want to convert all the Sines to Cosines using trigonometric formulas such as cos(x)=sin(x+pi/2). How can I do this?
121 views

### How to find the kth largest eigenvalue of a matrix, taking into account the sign? [duplicate]

I have a real symmetric matrix m (i.e. its eigenvalues are all real). Eigenvalues[m, {k}] will find the ...
94 views

### DictionaryLoopkup - pattern specification

I would like to find all Italian words that have a specific pattern of letter repetitions. Actually I'm looking for 6-letters words that have 1 letter repeated 3 times, a second letter repeated two ...
33 views

### Transfer Functions - Time Series depends on a second one

Suppose two time series ...
101 views

### Rearranging a Dataset

When processing a larger Dataset I came up do a point where I want to form a dataset with culumn heads from an intermediate structure. Here is an example of this structure: ...
51 views

### Vertex Names as Labels in GraphPlots

I'm trying to use GraphPlot to draw a Graph which is constructed from an adjacency matrix and am having trouble with the labels in the plot. I am doing (data is a silly example) the following: ...
63 views

### Substitutions and high order polynomials work extremally slow

I have the following code: ...
43 views

### when DSolve fails

I am doing this mathematical problem $c*G_{vv}+ d*G_{u} + e*G_{v} +f*G=0$, where $c, d, e$ and $f$- are constant coefficients. I already know that this is second order PDE and we classify it by ...
130 views

### Time-dependent mesh deformation

I want to display the result of a deformation with a mesh, but I solved the deformation with a time dependency. So I have two functions: uxsol[t,x,y] and ...
51 views

### Evaluating the real part of an expression

I want to get the Real part of this expression - shouldn't be too hard to evaluate. Why is Mathematica not evaluating but returning the same code? ...
22 views

### Error with numerical summation - how to specify “n choose r”?

I'm trying to do the following sum: NSum[((50000 - x) choose x)*(1/3^15)^x*((3^15 - x)/3^15)^(50000 - x), {x, 1, 4}] But I keep getting an error saying: ...
121 views

### Transform an InterpolatingFunction

I'd like to transform an InterpolatingFunction from NDSolve but can't figure out how. Here's an example. The equation I want to solve is ...
88 views

### strictly positive solution to $Ax=b$

How to find in mathematica one real strictly positive solution, if any, of $Ax=b$. A is rectangular matrix. Thanks
82 views

### Simple optimization 3D plot

Because this is such a simple example I am not going to explain the calculations. I am strictly wondering why I do get errors when plotting it. ...
53 views

### How to get the content size (in pixels) of the output in an output cell?

How to get the content size (in pixels, width and height) of the output in an output cell?
81 views

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50 views

### Find maximum number of instances with FindInstance[]

I understand that ...
110 views

### Unexpected result from StringReplace

The following works as expected. StringReplace["xxxyxz", "x" ~~ _ -> "ww"] "wwwwww" And so does this. ...
30 views

### Picard iteration method by yn(t) [on hold]

I am really bad with Mathematica, but I have an assignment due in my Real Analysis class that requires it. Here is the question: Denote successive approximations via the Picard iteration method ...
40 views

### Creating a List with Lists as entries [closed]

I'm trying to create a list A which contains 8 same elements. Each of the elements look like {0, 0, 0, 0}. I was able to do it ...
59 views

### Defining a function using a preceding expression

How can I automatically define a function inside my Mathematica code using a result (expression) that preceded the point of definition. For example: ...
46 views

### While subpartitioning the elements in list using GatherBy, can I corresponding subpartition the elements of an unrelated list?

If we have a list like the following: list1 = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}; And we use GatherBy to subpartition is according to a test function ...
99 views

### 3d phase portrait for a system of DEs

I'm trying to plot a phase portrait for a system of three differential equations so could anybody help? example for : ...
36 views

### Subpartitioning elements of a list based on some h[ri] == h[rj] test

If we have a list of elements: list = {r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12}; I'd like to further partition the elements into sets where, for some ...
102 views

### Collect is not giving me the result I expect

When I evaluate Collect[(a ((G m ω)/c^3)^(1/2) + b ((G m ω)/c^3)^(1/2)), c] I get this: ...
99 views

### Quantize a real-valued function?

I'm wondering if there's a built-in way in Mathematica to take a function whose output values are continuous, and quantize it to produce a step function. For example, I have the function ...
40 views

### nintegrate: greater accuracy possible

I've got the following piece of code: ...
90 views

### How to get the ranked order

data = {33, 6, 10}; Ordering[data] (* {2, 3, 1} *) What I really want is, 3 for 33, as it is the 3rd, if sorted; 1 for 6, as it is the 1st, if sorted; and 2 for ...
115 views

### Perturbation theory in general relativity using xAct

I'm trying to use the xAct Mathematica package for manipulating tensors, and I'd like to plug in a metric into the perturbation equations to first order in general relativity, and have everything ...
56 views

### Efficiently testing if every member of a sublist comes before every other member of another sublist

I have a list of elements - ...
30 views

### Mixture / Hierarchical Distribution from Conditional

How does Mathematica handle Hierarchical distributions. For example, if I have X|Y ~ Poisson(Z) Y ~ Exp(lambda) Z ~ Normal(0,1) First, of all, the distribution of X is only given conditionally and ...
98 views

### Get inverse of a matrix step-by-step [duplicate]

How can I get the inverse of a matrix step by step? An example: Given the matrix {{8, 2}, {3, 2}}, the result is {{$\frac{1}{5}$, -$\frac{1}{5}$}, ...
62 views

### Find all roots of a system of non-linear equations [closed]

Suppose I have a list of non-linear equations, and FindRoot returns different answers depending on where I start. I'm new to Mathematica. What is the best practice in mathematica for establishing all ...
41 views

### How to solve character encoding issue with Emacs, mathematica.el, and Mathematica 10?

I am successfully using mathematica.el in Emacs with Mathematica 10. However, I have some kind of issue with character encoding whereby when I call mathematica-execute on a Mathematica expression the ...
32 views

### Specify format to NotebookSave

When I save a Mathematica notebook using the front-end Save dialog, I can specify the format: However, the documentation for the NotebookSave command indicates ...
57 views

### How to add an extra column to a current matrix (list)? [duplicate]

a = {{-800, 1712}, {-801, 1713}, {-806, 1832}} TableForm[a] b = a[[All, 2]] - Min[a[[All, 2]]] How do I make a new matrix (list) whic looks like this ...
35 views

### Lightweight Grid saving to file

I'm trying to launching my first jobs on LightWeight Grid using ParallelDo. I have 10000 jobs, each of which returns a 1M output, which I would like saved to a file on the head machine, one file per ...
37 views

### SetAttributes to Cases creates problem in Suggestions Bar

I have encountered this issue when trying to set attributes to Cases (MMA V10.0.1). Any idea why? When I try to Open Wolfram Documentation in help menu (after this error) I got another problem.
105 views

### How can I trans-compile Mathematica into another language?

I'm looking for an exhaustive list of source-to-source compilers to all other languages, if any exist that is.