# All Questions

290 views

### Conditional Gathering of lists

Just need a little help with the GatherBy / SplitBy function(s). I have a list of random numbers here: ...
494 views

### Creating randomly oriented planes

I would like to create randomly oriented planes. This is how I'm attempting to do that: I create a 2 random unit vectors, $\mathbf{v}_1$, and $\mathbf{v}_2$, in the $x$-$y$ plane I assume that if I ...
191 views

### How to define function that can change patterns

Given time series data as follows: data = {{{2011, 1, 13}, 10}, {{2011, 2, 14}, 17}, {{2011, 3, 15}, 20}, {{2012, 1, 16}, 30}, {{2012, 2, 17}, 40}}; ...
449 views

### How to choose three points on the circle so that the triangle is not a right triangle?

I want to choose three points $A$, $B$, $C$ has integer coordinates on the circle $$(x+2)^2 + (y+1)^2 = 25$$ so that the triangle is not a right triangle. But I can not. I tried ...
390 views

### Performing Computations on Sets

I would like to find a permutation of $\quad S=\{\frac{1}{10}, \frac{1}{2}, \frac{4}{7}, \frac{3}{5}, \frac{2}{3} \}\quad$ that maximizes the sum of theses elements raised to unique powers: ...
133 views

### Compile not correctly initializing a variable defined inside Module

In the following example, inside the minimumX's Module, x is initialized to 1, but the ...
207 views

### Why is ReplaceAll behaving like this?

I'm learning to use the ReplaceAll function and I found the behavior of which is quite confusing. For Sqrt[f[x, y]] /. f[___] -> u Mathematica returns ...
577 views

### Functional programming and Do loops

I'm writing a Monte Carlo simulation. I'm using a Do loop to create the different simulations, iterating over different ...
267 views

### Defining Tags in Reap

I am trying to use Sow/Reap to replace Append in my code. The problem is that I need to ...
771 views

### BarChart frame labels

This barchart was tricky to style, and I had to resort to the legacy BarCharts`package. Any ideas how to omit the labels from the bottom edge? Ideally I'd also like ...
212 views

### What default theoretical distribution does Mathematica use in PearsonChiSquareTest?

I used Mathematica's function PearsonChiSquareTest to test whether the data were drawn from a normal distribution. As in the reference, I expected Mathematica to compare the result to a normal ...
231 views

### Fill out blanks with a upcoming number in a list?

I have a bunch of arrays looking like this: {"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", ...
926 views

### InterpolationOrder for ContourPlot

How do I acheive something like InterpolationOrder in ListContourPlot for ContourPlot? My ...
1k views

### How to sum up subelements of a list of unknown length

I'm simply looking for the {}+{} function for sublist elements of a list: (Parallel sums of elements) ...
718 views

### How do I change the Font in BarChart Legend?

Just wondering if anyone knows the proper Syntax to change the Text properties in the BarChart's ChartLegend. I cannot seem to figure out how to get Style[] to apply. Here is an example: ...
239 views

### Nest , Fold … is there an extension for more than 2 arguments?

Fold is an extension of Nest for 2 arguments. How does one extend this concept to multiple arguments. Here is a trivial example: ...
301 views

### How can I get $(r^{1/x})^x$ to simplify to $r$?

Simplify and FullSimplify do not simplify this kind of expression: $(r^\frac{1}{x})^x$. Consider ...
332 views

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108 views

### Alternative to NotebookLocate or NotebookFind

In Mathematica 8.0 and older, there are two ways to select cells based on cell tags. NotebookLocate["CellTag"]; NotebookGet[EvaluationNotebook[]] and ...
339 views

### How to align two overlayed plots, one being rotated?

I have two plots which I want to present on a single figure. The bottom left corner is a point of origin of the first plot. The top right corner is a point of origin of the second plot. Also, the ...
117 views

### Is it possible to use the global definition of a symbol as part of its new local definition set in a Block?

Consider the following expression: Block[{Print = CopyToClipboard}, doSomething[]] Now all calls to Print from ...
249 views

### Wrapping a function in count

I am working through the Programming Paradigms via Mathematica (A First Course) and am attempting to answer the following: Use recursion to count how many times the argument can have its square ...
382 views

### How do I create an ellipse bubble chart?

I have some data that I would like to plot as a bubble chart. The data is formatted as {{val1_mean,val1_sd,val2_mean,val2_sd},{val1_mean,......}}. What I would like to do is plot a bubble chart where ...
202 views

### How to automate x[i]→x_{i}?

I have several Mathematica expressions in which subscripts are expressed with square brackets. E.g. x[12] is meant to represent x12, etc. If I evaluate ...
471 views

### Efficient code for the Ten True Sentences puzzle

I am trying to solve Ten True Sentences Puzzle. Take a look at the following sentences: The number of times the digit 0 appears in this puzzle is _. The number of times the digit 1 ...
356 views

### Import values from tab separated file, change decimal point?

I have files that look like this: ...
220 views

### Change associativity of the @ operator

The @ operator in Mathematica is right-associative by default, i.e. f@g@h evaluates as f@(g@h) Is it possible to make the ...
257 views

### Differentiating an unknown solution to a PDE

Sorry if this question is too basic -- I'm not very familiar with Mathematica. I am interested in a way to systematically address the following sort of problem: Suppose that $u=u(x,y)$ is a function ...
457 views

### Expected Value: Strange/unexpected result

Assume $X$ is an exponential random variable with unit mean ($f_X(x)=e^{-x}$, $x>0$). I want to calculate the expected value of $\frac{1}{X}$. Since $X>0$, I am expecting that ...
340 views

155 views

### How do I define an argument pattern for a Head of NOT a given value?

I want to define a function f with an argument that matches only when an argument Head is NOT of a given value. I know I can define a pattern that matches the Head for an argument: ...
1k views

### Labeling points of intersection between plots

There are several answers where Mathematica used mesh points to show graphically where curve intersections exist. For example: Marking points of intersection between two curves or Is there a better ...
135 views

### How to ignore list elements when extracting with pattern matching

If I have a simple list, say {1, 2, 3}, and I want to extract a subset of the elements, what is the correct syntax? e.g. { i, _, j } = {1, 2, 3} I want i = 1 ...
121 views

### What should I call the messages that appear when the mouse moves over failed graphics output?

I attempted to evaluate the following Plot[x^2, {x, 1, 2}, PlotStyle -> {RGBColor[a]}] which, of course, failed. After the failure, putting my mouse over the ...
136 views

### Specifying optional arguments with variables

Perhaps this is poor programming on my part, but I would like to create a function that uses a variable as an optional parameter: var = 2; f[a_:var] := {a} The ...