23
votes
5answers
2k views

Mathematica Implementations of the Random Forest algorithm

Is anyone aware of Mathematica use/implementation of Random Forest algorithm?
13
votes
2answers
553 views

How can I get LineLegend to pick up my plot's BaseStyle?

The new legends functionality in version 9 really simplifies creating legends, and it automatically picks up the styles of the lines. ...
2
votes
1answer
166 views

Repeating the contents of one cell in another, in “real time”

How could I create two Input cells, such that when the first is evaluated, the contents of the first are copied to the second? So for example, there would be two empty cells - let's call them A and B ...
5
votes
2answers
367 views

Splicing a list of arguments into a function with Sequence

Not sure if this has been asked, but I have a fairly simple operation that I don't know the syntax for. Say I have an array with some values, and a function f that accepts an arbitrary number of ...
5
votes
1answer
201 views

Strange Behavior with RegionPlot

Consider the following code. RegionPlot[Print[{x, y}], {x, -2, 2}, {y, -2, 2}, PlotPoints -> 2] ...
3
votes
1answer
276 views

Wavelets: Relative error vs compression ratio

I need to plot the relative error vs compression ratio diagram of a discrete wavelet transform on an image, but no luck so far .. Here's the problem in short: random_image.jpg compress the image ...
2
votes
0answers
75 views

How do I eliminate the breaks in a 3D plot with a Max or Min function? [duplicate]

Whenever I make a 3D plot using the Max or Min functions, I get breaks in the plot when it switches from one expression in ...
19
votes
2answers
4k views

Creating a simulation of our Solar System

As the title says, my objective is to create a simulation of the motion of the planets in our Solar System using Mathematica. All the theoretical background regarding the equations of motion of ...
14
votes
1answer
574 views

Efficient code for tallying entries in very large lists

I am dealing with data sets containing tens of millions of (hashable) entries and simply using the Tally function to count the frequency of each unique list element ...
0
votes
2answers
402 views

Converting a list of replacement rules into a list of real values [duplicate]

The following command outputs a list of replacement rules. ...
8
votes
1answer
194 views

Locator Appearance

I am using LocatorPane with LocatorAutoCreate -> True. I would like to have the appearance of each new locator be different. ...
7
votes
3answers
545 views

Plotting a 3D list causes kernel to crash if x and y axes have vastly different scales

I have access to two versions of Mathematica, version 7.0.1 on Linux and version 8 on Windows. When I try the following two lines on version 7, the kernel quits when it tries to plot. In version 8 ...
1
vote
3answers
203 views

Using Outer with Compiled functions that accept more than 2 arguments

How does one use Outer with a compiled function that accepts 3 or more arguments. Alternatively, how does one create a compiled function with 3 or more arguments ...
2
votes
1answer
334 views

Using mesh for a single function inside Plot

Plot[{Sin[x], Cos[x]}, {x, 0, 10}, Mesh -> {{0, \[Pi]}}, MeshShading -> {Black, Red}] In the above, how can I specify that I want the mesh for just, ...
1
vote
1answer
191 views

Big spaces between legend positions

I am trying to make a legend for my plot. Actually, I made one, but I cannot understand why there are such big spaces between the legend positions. ...
3
votes
2answers
781 views

Parametric differentiable interpolation of a 2D data set

I have a set of data ...
11
votes
4answers
4k views

Why does Mathematica struggle with solving this equation?

Consider the evaluation of the following expression In[20]:= Reduce[ 1000 * 1.0609^t == 1500, t] ...
4
votes
2answers
450 views

ListLinePlot filling for accumulated data

I have 23 variables (energy production units) which take values for each hour of the day (energy dispatch table). Here is a PasteBin example of data. I am trying to represent the distribution of the ...
8
votes
1answer
303 views

How can I sequentially apply different graph embeddings?

Imagine I have some graph G, and I perform a graph embedding using a command like: ...
4
votes
2answers
324 views

Convert BSplineFunction into two Interpolating Functions

Is there a way to decompose a BSplineFunction output into two functions x[t], y[t] ...
4
votes
1answer
156 views

Extending a plot over a secondary variable

Apologies for the vague title; couldn't really think of a better way of putting it. I have a function $F$ of two variables, $\rho\in[0,\infty)$ and $f\in[0,1]$, that I wish to create a plot over ...
14
votes
3answers
428 views

Quick multiple selections from a list

What is the fastest way to make multiple selections from a list? Compiled methods included. For example, here are two methods for selecting a subset, compared:- ...
9
votes
1answer
655 views

What is the difference between prefix/postfix notations and map?

I am new to Mathematica and just experimenting with the different programming constructs. I have been looking at Map and how to evaluate a function for a list of ...
-1
votes
1answer
146 views

Solving an equation for asymptotic dependence of the solution on a coefficient

I have an equation I want to solve, so I entered the following into Mathematica. (x^(17/6))/(a^(17/6)) - (x^2)/a -1 == 0 where I assume $a>>1$ and $x$ is ...
0
votes
1answer
137 views

How to change variable that has been defined in PDE?

I have a PDE function that contains a variable (named ka). I want to plot the result of my PDE in 1 plot using several different ka values. However, I'm not sure about how to write down this equation. ...
5
votes
2answers
292 views

How can I retrieve the point coordinates from a LOG Plot after the data points were manually moved?

I'm having problems with getting coordinates out ofa ListLogLogPlot I basically plotted a list, then selected data points on the graph, moved these points around, ...
3
votes
3answers
731 views

Generating a random walk with defined step size

By the following I'm trying to generate a list of random coordinates (ex. 4) each within unit distance from previous one, starting from origin. What am I doing wrong? ...
3
votes
2answers
246 views

Eliminate several variables between five Conic_section equations

I want to eliminate x1, x2, y1, y2 between these 5 equations. I tried ...
5
votes
1answer
271 views

Processing and storing a graph with a large number of vertices s.t. k-hop neighborhoods are efficiently retrievable

I have an unweighted, undirected graph $G$ with $(v_1, ..., v_N) \in V$ vertices, where each vertex in the lattice represents a string of some length ($\leq 200$ characters), and I need to construct ...
2
votes
1answer
341 views

How can I get an exponent vector from monomials?

I am trying to get an exponent vector from a list of monomials. I am using the CoefficientRules command; however, it is returning a list that includes the ...
4
votes
1answer
214 views

Embedding Mathematica Console into a Java/.NET Application [duplicate]

I enjoy using Mathematica's notebook interfaces, but more specifically the autocompletion in each notebook. I'm in need of a way to put tons of Mathematica windows on the same page. It would be an ...
9
votes
1answer
290 views

EventHandler not working within DateListPlot (?)

I have some {date, value} data: data = Transpose[{AbsoluteTime /@ Thread[{2012, Range[12], 15}], RandomInteger[10, 12]}] ...
6
votes
1answer
196 views

Does new MMA9 Time Series support obsolete the old TimeSeries Package?

MMA9 includes a fair number of functions and symbols that seem to overlap with the old TimeSeries package. The new features are documented here and the old material is documented here. Some of the ...
2
votes
3answers
192 views

How can I find the points of B Spline functions for a specific range?

Based on this question: I have a list of bspline functions (nearly 1000) provided by applying BSplineFunction to a list of points. I want to get the points each of ...
2
votes
2answers
488 views

Replacing values of a function

I have recently starting using Mathematica and have recently come to what seems as an impasse in my understanding of the language. If this is too "tell me how to do it" I would certainly understand. ...
2
votes
2answers
200 views

What is the maximum real value for Compile?

Can one be found programmatically? The function I'm compiling, indicesOfMin, gives the indices of the minimum value(s) of a real-valued list, the parameter, in a ...
13
votes
1answer
423 views

Has anyone implemented cohomology for complex manifolds?

I'm investigating the cohomology of complex manifolds, and need to construct chain complexes, Mayer-Vietoris sequences etc. I use Mathematica for numerically tracing manifolds with geodesics, but ...
22
votes
1answer
696 views

Strategies for solving problems involving searches

As an example of a search-oriented problem, consider finding all constrained $n$-colorings of a graph. An "$n$-coloring" associates one of $n \ge 1$ colors to each vertex in such a way that no edge ...
5
votes
0answers
339 views

How can I change cursor style in InputField?

I want to make an InputField with a horizontal cursor, like this: Note that the blinking cursor should be horizontal and not the mouse pointer! Nevertheless, ...
20
votes
4answers
484 views

How to Initiate a queued evaluation from a Dynamic GUI without using a Button

I have a Dynamic-based GUI, and one part of it will kick off a calculation that could take longer than the default 5-second dynamic timeout. I know that ...
1
vote
2answers
220 views

Checking equality with ComplexInfinity and testing whether a function is (mathematically) undefined

This seems ridiculously basic, but I cannot find anywhere explaining how to do it. If you evaluate certain undefined functions like 1/0 or ...
1
vote
2answers
119 views

Why do I get two different results from StringLength?

I spent a reasonable amount of time to find the origin of an error in a larger code segment. ...
4
votes
2answers
1k views

How to generate a 3-d simple cubic lattice of length 4 in each dimension?

LatticeData["SimpleCubic", "Image"] The above line gives me a single cube (2 lattice points in each direction). But I want a lattice with 4 lattice points in ...
3
votes
0answers
97 views

Highlighting bracketing in Mathematica [duplicate]

I'm working with lists of lists of lists. Each box with information has a specific format like information = {{a},{{b}},{{{c},{d}},{e,{f}}},{g}} and so ...
6
votes
2answers
310 views

How can I convert this ListPlot to ArrayPlot?

I want to rewrite this code with ArrayPlot, ...
4
votes
1answer
117 views

Replacing a combination of terms

I have a quite simple question. I have an expression that looks similar to $T=\frac{1}{a_1}-\frac{1}{a_2}+1$ and I'd like Mathematica to use $A=\frac{a_1}{a_2}$ to reformat the expression (if ...
4
votes
1answer
220 views

Reproducing a graphic on Jensen's inequality for the probabilistic case

I am trying to reproduce the following graph on Jensen's inequality for the probabilistic case (source: wikipedia) but with the exponential function as Y, the normal distribution on the X-axis and ...
2
votes
1answer
243 views

Can I reduce a matrix inequality such as $\mathbf x^\prime\mathbf A\mathbf x > \mathbf x^\prime\mathbf x$?

I'm new to Mathematica. When I do linear algebra, I wonder if I can have an inequality such as $\mathbf x^\prime\mathbf A\mathbf x > \mathbf x^\prime\mathbf x$, where $\mathbf x$ is a column vector ...
2
votes
1answer
171 views

Discard functions with wrong symmetry?

I have functions of x, where x is the polar angle of spherical coordinates, i.e. ...
1
vote
2answers
239 views

How to incorporate functions within Do Loops

I'm attempting to repeatedly perform a simple algorithm with incremental changes of a parameter. I can easily express my changing parameter: ...

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