All Questions

176 views

How can I change the MPS format in Linear Programming samples of Mathematica?

I am trying to play with some linear programming examples of Mathematica as ExampleData[{"LinearProgramming", "blend"}, "Equations"]. It gives me the MPS format of ...
126 views

Reversing axes to get Poiseuille profile [duplicate]

I am trying to plot my velocity profile, similar to this plot (not the arrows, just the shape) Here is my function ...
153 views

A weird thing about ListPlot3D [duplicate]

I plot the function f(x,y). x goes from 0 to 25 and y goes from 0 to 12. So, my plot should look elongated since the range of x is twice as long as the range of y. The problem is that, mathematica ...
92 views

RSolve and incomplete gamma function

I am interested in how Mathematica uses the incomplete gamma function to solve difference equations. For example, if we have this inhomogeneous, 2nd order equation and use ...
396 views

How can I make a cell that contains an image which can be shifted?

When you're looking at some help pages, they may have cells containing images which can be shifted within the cell by left-clicking and dragging the mouse. Here is a sample: ...
167 views

Why does Map[Unevaluated, Table[PauliMatrix[i], {i, 1, 3}] give {Unevaluated[{{0, 1}, {1, 0}}], Unevaluated[{{0, -I}, {I, 0}}], Unevaluated[{{1, 0}, {0, ...
826 views

ODE and BVP: NDSolve errors

The mathematical problem is shown here. I tried to solve writing the ...
675 views

A matrix-vector cross product

I want to do a cross product involving a vector of Pauli matrices $\vec \sigma = \left( {{\sigma _1},{\sigma _2},{\sigma _3}} \right)$; for example, $\vec \sigma \times \left( {1,2,3} \right)$. ...
133 views

Strange behavior of Integrate

I'm trying to calculate the following integral using Mathematica 9.0.1.0 a11=Integrate[Abs[Sin[b+x]],{x,0,2*\[Pi]}] This should be a simple problem; however, it ...
195 views

Notebook UI: Autocompletion - Display function arguments when typing?

Is there a setting to display the required arguments of a function when typing as Visual Studio, Matlab, etc. does?
290 views

In what situation is the use of Directive required?

Sometimes I see code samples in the document or in this site using Directive, but I haven't yet find a case that Directive is ...
108 views

Expand List Operation

On applying a multiplication and subtraction on a list, like so: x = 2y - 4; Where y is a list containing fractions of complex numbers generated from dynamic ...
765 views

How to plot and solve the numerical solution of a integro-differential equation

I have a integro-differential equation of the form $y'(t) = - \int_0^t {y(t_1 )} e^{t_1 - t} dt_1, {\rm{ t}} \in {\rm{[0,10], y(0) = 1}}$ My code is: ...
147 views

question1: (code 1 something wrong, Why? and how to overcome this to achieve the next code's effect) ...
74 views

Replace expression using a tuple

Given an expression in x, y, z (for example), and a list with three elements, like ...
405 views

FourierSeries for rational function looks wrong

I have the following code: ser[x_] = FourierSeries[(\[Pi]^2 + a)/(3 x^2 + a), x, 10] // N // Chop It gives me some series, which I then try to plot. And ...
359 views

Checking if an expression is equal to zero

I have 6 points in $\mathbb R^3$ as follows: ...
144 views

Rearranging a set of numbers

I have this set of numbers, that is a range of prices (ie 6-10) and a quantity of products (5) ...
531 views

Calculate variance of random walk?

How can I symbolically calculate the variance of the following random walk in Mathematica? Given several discrete random variables such that $p(Z_i=1-2k)=p$, where $k$ is a small real number, and ...
131 views

Cannot run Mathematica C-interfacing examples 'factor'

I am trying to run a Mathematica example concerning Mathematica interfacing issues with C programs. In particular I am trying to call a Mathematica function from C. Example ...
169 views

How can I combine two Pick expressions into one?

I want to speed up my code, i.e., replace Select by Pick. I think using two Pick ...
1k views

Compiling more functions that don't call MainEvaluate

I would like to use Compile with functions defined outside Compile. For example if I have the two basic functions F and G F[x_] := x + 2 G[x_] := x And I want ...
377 views

What does the Error Message in DSolve really mean?

Having this ordinary non linear differential equation $$y'-x^2 (y+1)\cdot (y+2)^2= 0$$ with the boundary condition $y(4)=2$. When trying to solve this one with Mathematica by using ...
238 views

how to reduce the time to calculate triple integral

i want to evaluate the following integral, but it takes 15 min to do it. i must reduce the time to calculate it, i have to do a table and create a graph, but takes too long. anyone have an idea ? ...
666 views

Plotting heat equation in a Manipulate expression

I have a 2D heat equation $u_t = \alpha (u_{xx} + u_{yy})$ with conditions: $u(x, y, 0) = 300$, $u_y(x, 0, t) = \mu_1(x)$, $u_y(x, 1, t) = \mu_2(x)$, $u(0, y, t) = \mu_3(y)$, \$u(1, y, t) = ...
151 views

How to dynamically change the Appearance of a control in Manipulate?

How can I dynamically change the appearance of b? Strangely it works for the Enabled state but not for the Appearance. Thanks. ...
253 views

Create a table with inline conditions

I am trying to create a table with conditionals inline. For example, I'd like to create a 2 dimensional table like this: ...
211 views

FindFit: Fit that is always lower - Change of Norm?

I am trying to find a fitting function for a multidimensional set of data. I will have to find a fitting function that is always lower (conservative) than the data fitted. The easiest way is to look ...
60 views

Don't pollute outside context when solving equation from the outside

This code works fine only if a is not defined in the outside context: ...
251 views

webMathematica interface for Mobile apps

I was reading about webmathematica but it has mentioned that it is for websites and mobile apps depend on wolfram alpha to get its work done. But since exact mathematica code doesn't work in alpha, it ...
285 views

How to populate a table using a rule replacement

I am trying to populate the rows and columns of a table by using a rule replacment. To generate a table that looks like this For example Sc would be row 1, column 1. An example of a record looks ...
131 views

How to track dynamically generated manipulators?

In the code below the manipulators that are generated from the stakes buttons are not tracked by the Manipulate expression that contains them. How can I make the ...
127 views

Minimize failing on a polynomial

Calling: Minimize[{-0.4877 - 0.1190 r^2 - 0.1885 r^4 + 2.9703 z - 0.5531 z^2, 0 <= z <= 3.5 ∧ 0 <= r <= 1.75}, {r, z}] returns ...
135 views

direct assignment to the element in a Table

I have already asked a related question here why set values in this way doesn't work? But I think I have to write the question which I encountered explicitly? ...
2k views

Open-source IntelliJIDEA plugin to support Mathematica development

Although we already had a question asking for development alternatives to Wolfram Workbench, I want to ask a more specific question: One of the most advanced IDE's especially for Java programming ...
639 views

How can I conveniently call igraph through RLink?

Mathematica has lots of functions for working with graphs, but this functionality is not yet as mature as the igraph library. It is useful to have access to igraph from Mathematica, both for ...
516 views

Mathematica equivalent of regex '\w{2,3}'

It beats me to write the Mathematica pattern equivalent to the regex: \w{2,3} Any ideas?
248 views

How to normalize parts of matrix elements?

To normalize the last 2 or more columns of a matrix, ...
285 views

DownValue “associative array” to list? [duplicate]

I have a "sparse array" like this arr[1.5]=0.4, arr[3.5]=0.7, arr[7]=0.3 which is not really a sparse array since the keys are not all integers. This is like a ...
97 views

Help generating dynamic manipulators?

I would like to generate dynamic Manipulators for each of the selected buttons in a ToggleBar. How can I keep the state of each Manipulator in a variable? I would like to later access the values of ...
386 views

Manipulate slider unresponsive after suspend in Linux

I've tested Linux Mathematica versions 7-9 on various Linux distributions, with identical problem: after suspend/resume cycle my Manipulate controls (i.e. sliders&buttons) appear unresponsive, ...
388 views

CoordinateTransform from Cartesian to Spherical

I have a set of coordinates on the sphere in terms of cartesian coordinates. I would like to convert them to spherical data points. However, when I try to convert the point {0, 0, 1} it tells me that ...
54 views

Problem using replace to simplify logarithms [duplicate]

Is there a way to combine logarithm terms like 9 m Log[m]-9 m Log[M]+16 m M Log[m]-16 m M Log[M] into ...
329 views

How to insert a zoom inside the main plot

As the title indicates, I want to add inside the main plot (preferably at the lower left part) a zoom. Here is the corresponding Mathematica code: ...
291 views

Exporting PDF file - incorrect graphic [closed]

I export graphics to PDF using: Export["/path/figure.pdf", plotname] It gives me more than enough quality for PDFLatex. But somehow, some exported plots have ...
243 views

Is mathematica storing information it shouldn't store?

I'm seeking to find solutions to a numerical integration with a large set of parameter combinations (basically, I'm doing a brute parameter sampling). Yet, I believe the memory of the computer is ...
306 views

Join all square root expressions?

Sometimes I observe Mathematica produce expressions exactly like the following after a simplification step: $$\frac{a+\sqrt{-(1-b)}\sqrt{\frac{1}{b-1}}}{\sqrt{c}\sqrt{\frac{1}{c}}}$$ Now, any ...
331 views

Solve equations real and imaginary part separately

For my system of equations, the procedure described in Solving complex equations of using Reduce works no more. How can I separate the real and imaginary part of ...