1
vote
1answer
218 views

Weighted Kirchhoff Matrix?

I have a weighted graph and I want its graph Laplacian matrix (what Mathematica calls the Kirchhoff matrix in the unweighted case). Is there an easy way to get this? For example, the command: ...
11
votes
2answers
664 views

Make good looking histograms from frequency data

I allways do my calculations in Mathematica and I make my histograms using ROOT language. However I am wondering is it possible to make good looking histogram inside Mathematica? A sample of what I ...
1
vote
2answers
597 views

Area of the largest rectangle bounded by $y=x^2$ and the x-axis within the unit interval

I am trying to find the area of the largest rectangle (whose sides are parallel to the coordinate axes) contained in the region bounded by the graphs of $y = 0, y = x^2,$ and $x = 1$ using ...
1
vote
1answer
60 views

Is SynchronousUpdating->False supposed to make this simple Dynamic example work?

x = 0; Dynamic[{x, Button["+1", Pause[6]; x++]}, SynchronousUpdating -> False] The documentation states that Dynamic and Manipulate will abort synchronous ...
4
votes
0answers
193 views

Strange result from evaluating a Limit expression

When I evaluate the limit of (1-Cos[x]) Sin[1/x] at x = 0 in Mathematica 9, I obtained ...
2
votes
1answer
134 views

Obtaining a function from the function

Assume that; ...
1
vote
1answer
126 views

Constrain plot points to below a certain line

I have a set of curves that take on large values when approaching 1. I'm trying to create a straight line with certain slope and then truncate the plot for any curve that goes above that line for any ...
0
votes
1answer
161 views

Difference between FindInstance and NSolve

Assume that ...
4
votes
2answers
518 views

WhenEvent in NDSolve

How come this doesn't work as I intended? ...
1
vote
1answer
183 views

FindMaximum inconsistency

The code below seems to work for n<11. But for n=11, and above, it outputs newa then just outputs "beep" sound. WhyTheBeep says "The kernel Local has quit ...
1
vote
1answer
373 views

How to guess initial complex value for FindRoot

I have to solve a transcendental equation for a parameter, say $\beta$. Now, the $\beta$ has a range from $ik$ to $k$ where $i$ is the usual imaginary root $\sqrt{-1}$ and $k$ is a real number. ...
0
votes
4answers
827 views

Specify a variable as an integer

I have a formula that always evaluates to a certain number for any variable X under one condition that X is an integer and ...
0
votes
2answers
219 views

Find white regions in image

At the white regions of this image I want to add a few random arrows. I would like to realize two different of adding the random arrows: The arrows may not leave the white region The arrows have to ...
4
votes
2answers
811 views

How do you configure Mathematica 9 to automatically evaluate all notebooks?

I have a Mathematica 6 course that I am using in Mathematica 9; there is no updated version. Every time I open a notebook I have to go to the Evaluation menu and click on "Evaluate Notebook". Is there ...
9
votes
2answers
550 views

Why does Integrate declare a convergent integral divergent?

When I try this command Integrate[1/Sqrt[(s^2 - u)^2 - 1], {s, m, Infinity}, Assumptions -> u > 2 && m > 10] Mathematica declares that the ...
6
votes
2answers
562 views

Export to CSV is very slow - can performance be improved?

I have to provide data exports from Mathematica to CSV format and it is very slow compared to other formats as can be seen in the following table: JSON, 15 sec, 8.4 MB TXT, 23 sec, 5.6 MB XLSX, ...
3
votes
1answer
512 views

Non commutative multiply- expand expression

I began to use Mathematica a few days. My problem is: How to expand expression like $(a+b)*(a+b)$, where this multiplication is non commutative? Mathematica can do this?
3
votes
1answer
238 views

How to troubleshoot CUDALink?

This is a follow-up question from linking the libraries for CUDALlink in Ubuntu 12.10. The tests that I execute (CUDAQ[], ...
1
vote
0answers
61 views

Finding Maximum Root [duplicate]

How can I find the greatest root for a polynomial if the polynomial degree is very large. One way is using NSolve. This command can find all roots in numeric. Then, ...
7
votes
4answers
579 views

How to collect terms with positive powers in polynomial

I am trying to collect all terms with non-negative powers of $x$ in polynomials like $\frac{1}{x^2}\left(a x^2+x^{\pi }+x+z\right)^2$ First expand the polynomial ...
2
votes
1answer
111 views

strange output from ToExpression

I want to set constraints to my parameters, e.g., "m", but Mma gives nonsensical output. How could I avoid this phenomenon by using another but "equivalent expression"? Or, is this just in my computer ...
1
vote
2answers
218 views

What ways are there to convert an Integer to a list of digits?

How can I convert an Integer to list of numbers? For example: 781049 ==> {7, 8, 1, 0, 4, 9} What are the possible ways of ...
6
votes
0answers
166 views

Calculating the rank of a huge sparse array

By virtue of the suggestion in my previous question, I constructed the sparse matrix whose size is $518400 \times 86400$, mostly filled with $0$ and $\pm 1$. Now I want to calculate its rank. Since ...
3
votes
2answers
416 views

Triangle mapped on a sphere in $\mathbb R^3$?

How can I map a triangle on an sphere? I want to visualize (plot or animate) it for my student in my Non Euclidean geometry. I have no restrictions on the triangle's kind or on the sphere in $\mathbb ...
3
votes
3answers
112 views

Can I put subscripted parameter values into a package?

When defining packages, can I put parameter values alone or along with functions into a package in subscripted form? ...
1
vote
2answers
1k views

Efficient ways to create matrices and solve matrix equations

I am attempting, for the first time, to use Mathematica to do some serious linear algebra. I would like to solve systems of equations of the form $$U_{n n'} f_{n'} = b_n.$$ I have an expression for ...
2
votes
1answer
595 views

Tutorial for basic numerical methods for PDEs

I'm afraid this is probably not going to be a "good" question, but I'd like to use Mathematica to learn about basic numerical schemes for solving pdes. For example, I'd like to compute the solution of ...
5
votes
1answer
155 views

Find the domain in which a sequence converges

I seem to have a lot of problems in the format of: Given the sequence $a_n=\frac{n^\alpha+1}{2n^8+5}$, for $\alpha > 0$, find the values of $\alpha$ such that the sequence converges. However, ...
5
votes
1answer
139 views

How to read off coefficients of tensor-like expression in a speedy way?

I am considering identities involving t[a, b, c, d, ...], where number of indices is fixed. t has the cyclic property so that ...
5
votes
5answers
3k views

StreamPlot in Polar Coordinates

I want to use StreamPlot to map out the field lines of an electric field $\mathbf{E}$ given by $$ \mathbf{E} = \frac{3D}{4r^{4}}(3\cos(\theta)^{2}-1)\mathbf{\hat{r}} ...
5
votes
2answers
768 views

Mathematica cannot find CUDA driver

I have successfully installed CUDA 5.0 on my Ubuntu 12.10, with driver 304.54, toolkit and samples. Running deviceQuery gives me a successful output: ...
0
votes
1answer
241 views

double integration

I want to evaluate a double integral, but the limits of one integral is a function of the second. Like this ...
6
votes
1answer
264 views

Speeding up the non-negativity algorithm for multilinear function with interval probabilities?

The algorithm is a branch-and-bound algorithm that calculates the non-negativity of a multilinear function with interval probabilities. The lines 9-11 has an optimization that is explained on the ...
2
votes
2answers
258 views

Efficient code for building a big list

I would like replace the following code ...
7
votes
8answers
1k views

Defining a function that completes the square given a quadratic polynomial expression

How can I write a function that would complete the square in a quadratic polynomial expression such that, for example, CompleteTheSquare[5 x^2 + 27 x - 5, x] ...
1
vote
2answers
344 views

Output format in MatrixForm

I have a correlation matrix, which I want to display in the following format: 2 decimal places (e.g., -0.56) number signs "+" and "-" (e.g., +0.76 or -0.34) I've tried many different things, but I ...
10
votes
3answers
2k views

Composing an image with a plot

I'm trying to illustrate the solutions to a textbook problem dealing with quadratic functions. This will involve plotting a quadratic and overlaying the plot and the image. Here is the textbook ...
1
vote
1answer
258 views

Generating a list of symbolic coefficients [duplicate]

I am trying to do something which I assume should be very simple: I want to generate a list with symbolic coefficients that looks like this: ...
1
vote
1answer
174 views

Recursion evaluate Table power exceeded limit

I wrote 2 simple recursive functions for calculating the power of a table. pol3[Tb_List, n_Integer?Positive] := If[n == 1, Tb, Tb.pol3[Tb, n - 1]] and ...
2
votes
2answers
654 views

Putting NDSolve into ParametricPlot

I am having issues using Manipulate to plot the (numeric) solution to an ODE for different parameter values. I have a code that has several stages, which seem to ...
2
votes
1answer
123 views

How to label vertices in a grid with random integers?

I would like to assign each vertex a random number with the minimum bound equal to the smallest vertex and the maximum equal to the value of the largest without repeats. For example, in a 20x20 grid, ...
5
votes
0answers
86 views

Modify NDSolve`StateData (if possible)

I am trying to solve a PDE that needs to be scaled constantly (refer to this). @andre suggests I modify NDSolve`StateData. Now, the problem is, I'm not used to ...
2
votes
1answer
124 views

Is it possible for me to explicitly specify a point list for SpatialGraphDistribution?

The function RandomGraph[SpatialGraphDistribution[n, r]] generates a random geometric graph over $[0,1]^2$ where vertices are connected if they are within a ...
8
votes
2answers
275 views

Why doesn't DumpSave work for elements created within a local notebook context?

I recently noticed that when dealing with notebooks with local context, I cannot successfully DumpSave variables, or, rather, when I call ...
2
votes
1answer
138 views

Determining whether two k-chromatic graphs are equivalent (not simply isomorphic) using IsomorphicGraphQ?

In a previous question of mine, I asked whether Mathematica's built-in routines could determine an isomorphism for two $k$-chromatic graphs, Determining whether two $k$-chromatic graphs are isomorphic ...
0
votes
1answer
271 views

DataRange problem in a ListLinePlot within a Manipulate

I'm trying to create a simulation of a set of lists with Manipulate[] and ListLinePlot[]. However, as my simulation starts with ...
3
votes
1answer
66 views

Restricting a plotted expression to reals in a Manipuate

I have an expression from which I'm trying to create a plot that I can manipulate. The expression contains Abs, and I only want to have it evaluated for reals. What ...
1
vote
2answers
1k views

Discrete FFT of non-periodic signal excited by short pulse

Say I have a signal F(t) which represents a excitation by a pulse (so it is not periodic and declining to zero amplitude). According to this answer, for instance, ...
1
vote
2answers
383 views

Implicit differentiation to find the slope of the tangent line to the graph at the indicated point [duplicate]

I used ContourPlot to plot the graph of x Sin[Pi y] - y Cos[Pi x] == 1 with the following input: ...
2
votes
5answers
326 views

Creating ordered triplets from an Excel sheet

I have an Excel sheet of the form: " " a b c 1 R S T 2 U V W 3 X Y Z Where every entry is a number (except the blank quotes, ...

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