# All Questions

115 views

### Operator operation

There are two basic operators r={x,y,z} and p=-I*h*{D[#,x] , D[#,y], D[#,z]} &. The angular momentum operator is defined as ...
57 views

I would like to obtain a "slick" implementation of A*-search algorithm on Graph objects, using the built-in BreadthFirstScan (if that is possible at all). I noticed that BreadthFirstScan is static in ...
117 views

### What can I do to improve the performance of my calculations?

I'm trying to express a simple probability problem in Mathematica, but am having trouble getting my calculations to execute at a reasonable speed. I have an object whose unknown location is modeled ...
70 views

### How to define a function $f(x)$ such that $f(1.5)=1.5$, $f(1.)=1$, $f(0.)=0$, etc.?

How to define a function $f(x)$ such that $f(1.5)=1.5$, $f(1.)=1$, $f(0.)=0$, etc.? Namely, if $x$ is an integer with a decimal point, $f(x)$ returns the integer only, otherwise returns $x$. This ...
236 views

### I don't understand ListCorrelate! [closed]

I want to solve a PDE equation (like Schrodinger equation) using finite difference in Mathematica. I don't understand what this code does! ...
126 views

### Convert frequency counts to long notation in Mathematica

I have a series of frequencies of values, e.g. 5 times 1, 10 times 2 and 5 times 3, as in list={{1,5},{2,10},{3,5}} and I would like to convert this to long ...
120 views

68 views

### Mathematica quits calculation automatically

I have this little program that is adopted from a Wolfram demonstrations project (link here: http://demonstrations.wolfram.com/PercolationOnASquareGrid/). I want to see what happen if I increase the ...
136 views

### Mathematica Compute Time Is Extremely Long (Integrate simple function with parameter scan)

I was wondering if you can help. I have a set of equations I need to solve for a list of parameters; entering each parameter value and solving anew each time is simply not economical. I found a way ...
94 views

### Why does Mathematica list the variables in a double integral backwards? [closed]

I am an advanced novice Mathematica user and have done a fair amount of single-variable calculus things with it. This semester I am using Mathematica for multi-variate calculus and when I tried to ...
167 views

### Plotting a frequency function

I have a list of numbers and I want to plot the fraction of numbers >= k against k which will naturally be a decreasing curve. How do I do that?
275 views

### Coloring a honeycomb structure

I am trying to generate a honeycomb structure. With the help of this MMA.SE question & this website, I got ...
124 views

### Help to solve the equation with RungeKutta method [closed]

I need to solve this equation. v'[t] + v[t] == 1/(1 + Exp[-v[t]]) I tried to solve it using RungeKutta method described in Wolfram ...
95 views

### Setting an initial value for ListAnimate?

ListAnimate is fairly similar to Manipulate, but while Manipulate has a simple way to request an initial value for the manipulation parameter, I haven't found a way to tell ListAnimate to start with a ...
130 views

### How can I get precise frame rates in dynamic?

I've been the Spritz sdk in my ios apps, and I love it. For funsies I wanted to see how much less code a mathematica version would take! Using dynamic I get a nice result, shown below in code. ...
285 views

### Are solid spherical harmonics implemented in Mathematica?

In certain applications, solid spherical harmonics can be very useful. They are essentially the usual, 'surface' spherical harmonics, with the appropriate power of the radius inserted: ...
438 views

### Package for representation of groups (group theory)

I wanted to know if there is a package which allows to compute representations of a group like the definition representation, adjoint and so on (for example the Pauli matrix for $SU(2)$ if I specify ...
82 views

### Creating If statements programmatically [duplicate]

I want to write an algorithm that returns a sequence of numbers, starting from a specified point but stopping once a criterion has been reached. For example ...
37 views

### How can I select two lists from a list of lists so that I receive the system of equations has only rational solutions?

I want to make a sytem of equations has the form $$\begin{cases} a_1x^2+b_1y^2 + c_1xy+d_1x + e_1y+3=0,\\ a_2x^2+b_2y^2 + c_2xy+d_2x + e_2y+3=0. \end{cases}$$ so that the given system of equations has ...
70 views

124 views

### Opening notebooks from Workbench on Mac OS X?

I recently switched from Windows 7 to Mac OS X 10.9.2 for Mathematica development, and have set up Mathematica 9.0.2 and Wolfram Workbench 2 (running under Eclipse Kepler). Most everything works ...

15 30 50 per page