0
votes
0answers
27 views

Constructing a list of equations from a table with two indices [closed]

I need to make a list of equations like this {x + y == 0, 2x + y == 0, x + 2y == 0, 2x + 2y == 0} I tried ...
0
votes
0answers
28 views

“Why the Beep?” error when trying to save the document

I am new to Mathematica. I installed it yesterday, opened a tutorial video and after that tried to save my notebook but I got the following error message: Whenever I try to save my document I get ...
0
votes
1answer
63 views

Variable change

If I have the following Hamiltonian: ...
0
votes
1answer
61 views

NIntegrate vs. summation

I' m interesting in distributions of points on sphere, plane figures etc. Especially for small number of points: 1, 3, 7, ... It seems that good criterion for uniformity of distribution is some ...
0
votes
0answers
31 views

Linear system of stochastic differential equations

I want to solve linear system of differential equations of the following form $$X'[t] = M.X[t] + R.X[t]*\lambda[t]$$ where $X[t]$ is a vector of coefficients I want to have at time $t$, $M,R$ are ...
0
votes
1answer
58 views
2
votes
1answer
51 views

Export a Pyramid to VRML format

How do you export a Pyramid to vrml format in Mathematica ? I have been trying to do this the following way ...
3
votes
2answers
59 views

Slow application of `Outer` on a matrix

I have some performance issue with the calculation of a gaussian kernel applied to a not-that-large dataset. I'm not very good with performance tuning in Mma and I have the feeling this one could be ...
1
vote
1answer
42 views

Plot with two LabelStyle

I need to plot a graph with two different colors for the axis labels. Not working examples Plot[Sin[x],{x,0,2\[Pi]},Frame->True,LabelStyle->{{Red, Black}}] ...
6
votes
2answers
144 views

There is an issue with Manipulate in which it updates its argument twice in V10

I have asked this question before (here) and I thought that the issue is only when moving the Notebook window. It appears that Manipulate is working in weird manner. ...
0
votes
0answers
25 views

Operator Precedence [closed]

I want to know the operator precedence of this equation. I'm new. Please kindly elaborate your answer. sigma=x*y+k*H(r) mod q Your helps means a lot!
2
votes
1answer
51 views

Export Multiple Arrays Into a Single Worksheet with Column Headers

I'm importing financial data into Mathematica, creating column headers for each array and exporting to Excel. The code below accomplishes most of this, but it creates a different worksheet for each ...
0
votes
0answers
43 views

How to get an email address from a user [closed]

I need to obtain the email address of a user. Two problems arise: When I display an example email such as johndoe@domain.com, it displays with quotes which are very distracting to the user. If the ...
3
votes
1answer
132 views

Mysterious spikes in Plot3D

I am using Mathematica 9 and get these strange spikes when I plot the following simple function. I have seen a previous post about this but cannot figure out what is wrong with the following code. ...
0
votes
0answers
34 views

Errors when thickness is reduced solving 2D cylindrical heat conduction equation

I am trying to solve the heat conduction equation in cylindrical coordinates with a defined heat generation within the volume (a thin disk, with different heat flux BC top and bottom). The problem is ...
2
votes
1answer
88 views

How to plot on complex plane with Mandelbrot set

I essentially want to treat the Mandelbrot set plot as a normal plot so that I can plot arrows and points on top of it. This is what I want to do but it gives me an error: ...
1
vote
0answers
74 views

Simplifying $e^x>1$, is this a bug?

Simplify[Exp[x] > 1, x ∈ Reals] results in no simplification, although Reduce[Exp[x] > 1, x, Reals] correctly ...
2
votes
2answers
80 views

How to change the font color and size of tick labels by default

I've read Mike Honeychurch's answer here, and while it tells me how to change the font size on all of my plots, that size change affects (I think) all text on the plot. I would like to be able to make ...
1
vote
1answer
46 views

Are all of the numbers in my file legitimate hex numbers

I have about 10,000 hexadecimal numbers (32 digits each) in an excel file, in one column. I want to verify that all of them are indeed hexadecimal number and that no other characters are present. My ...
0
votes
1answer
59 views

Differential equations DSolve constant issue

After using DSolve to a set of differential equations, three constants arise. They are C[1], C[2] and C[21]. I have checked thoroughly that there are no C[3], C[4],....C[20]. It is quite mysterious to ...
1
vote
1answer
43 views

Strange Issue with RowBox

Can someone explain why this notebook [RANGEWORKING.nb] ...
3
votes
1answer
60 views

Output function control and manipulation for efficient computation

I have taken note of a similar post related to modifying function parameters. I tried to adapt Kuba's solution to this post but I can't get it to work. I will illustrate my problem using a similar ...
1
vote
1answer
102 views

Show plot legends for multiple curves in one plot [closed]

I have 5 curves, figure1a0, figure1a001, figure1a01, figure1ae01, and figure1ae001,. I display all these curves in one plot with Show. I want to give a label to ...
2
votes
0answers
51 views

WSTP (formerly MathLink) problem

I recently set about to re-compile some old (2008-2009) applications that use MathLink in preparation for creating new, modified versions. Mathlink has been deprecated but WSTP seems like a fairly ...
13
votes
1answer
649 views

Is Mathematica `ContourPlot` function really so efficient?

I wanted to find the roots of the function $f(x,y)=\sin(3.2x)\sin(1.3y)-2.1 \sin(1.3x)\sin(3.2y)$. This is what the function looks like: ...
0
votes
0answers
20 views

Tricks to speeding up optimisation of a function involving a heavy integration

This is the code, and energycoeffs[] is the function that takes in a dxd matrix and spits out a scalar value. ...
0
votes
0answers
24 views

How to evaluate NMinimize inside a function

I want to define a function that returns a sum of differences of some points to a given function. To obtain these differences I would like to use NMinimize, but if I implement that straightforwardly, ...
0
votes
1answer
24 views

Why Table is not giving me the same sequence for eigenvalues of matrix

Let consider a matrix and evaluate the time dependent eigenvalues M[t_]:={{Sin[t],Cos[t]},{t,t*t}}; e1[t_]:= Eigenvalues[M[t]] Now If I evaluate ...
0
votes
2answers
55 views

Convolution of a piecewise function

I want to find the convolute the the functions in the Convolve command ...
1
vote
1answer
40 views

Error with using SortBy in a Map [closed]

I have a data set in the following format: SomeData = {{a, 1, 2}, {b, 2, 3}, {c, 3, 4}, {b, 1, 9}, {c, 1, 10}, {a, 2, 3}, {a, 3, 8}, {b, 3, 4}, {c, 2, 9}}; The ...
3
votes
0answers
55 views

Efficient image stacking

I have a list of lists of images that I would like to stack and create mean images for each list of images. Images are .jpg files 2592x1944 pixels large. Each list ...
0
votes
1answer
37 views

Vector Analysis in Version 8

Silly question. Why does Needs["VectorAnalysis`"] Grad[Sin[x^2 + y^2], {x, y}] give the error Coordinates::invalid: "{x,y} is not a valid coordinate system ...
3
votes
0answers
43 views

WorkingPrecision in LogLogPlot creates wrong plots

I seem to have found a bug with LogLogPlot in version 10. If I specify a working precision, the function produces total garbage. Here is a simple example. The first case, without WorkingPrecision ...
5
votes
2answers
154 views

Drawing a path which realises the diameter of the graph

So I enter a (0,1) adjacency matrix and I get the following graph: The diameter of this graph is 4. How can I ask that two vertices which realise this diameter be drawn with different filling ...
1
vote
1answer
57 views

How to impose normalization condition (not initial condition) on DSolve or NDSolve?

I have a set of differential equations (or DAEs): $\begin{cases} 5x_{2} + 3x_{4} + 3x_{5} = \frac{dx_{1}}{dt}\\ 5x_{1} + 5x_{2} + 5x_{3} + 3x_{4} + x_{5}= 0\\ 3x_{2} + 3x_{4} + 10x_{5} = ...
1
vote
0answers
37 views

Is it possible to circumvent this overflow?

I'm trying to evaluate the following function numerically: $ f(A,B)=\frac{2A\pi ^{5/2} (-1)^B}{(A!)^2B!} \, _4\tilde{F}_3\left({\frac{1}{2},1-A,1-A,1-B\atop ...
1
vote
1answer
66 views

How can I copy & paste cell styles?

In Mac's mail app the key shortcut "command + option + c" gives a copy selected text style and "cmd + opt + v" pastes the style. Is there a way to achieve this with cell styles? The keyboard part is ...
5
votes
2answers
209 views

Evaluating complicated trig without resorting to numerical methods

I have an angle theta given by Kx = (2/Sqrt[3]) ArcSin[Sqrt[3/10]]; Ky = (2/3) (ArcCos[(1/5) Sqrt[7/10]] - Pi); theta = Cos[ArcTan[Kx, Ky]]; This evaluates, by ...
0
votes
0answers
17 views

Error Using Mysql In Mathematica

I'm using Mathematica, and accessing mysql through mysql (Connector/J). When I try to update a field in my table using WHERE statement, all the rows get updated ...
6
votes
1answer
90 views

Context of localised (dynamic) symbols

When you localise a symbol with Module, the created unique symbol is usually in the current context. There seems to be an exception to this which has further ...
2
votes
1answer
34 views

Plotting Vectors in Mathematic at lat/long positions

I have some current data that I want to plot in Mathematica. The first two columns are the latitude and longitude respectively (longitudes are negative b/c it is west of the prime meridian and all ...
2
votes
3answers
94 views

Plot a table of lists

I want to make a point plot of a table with lists in it. Assume I have data like this: data={{1,2,3,4},{5,6},{1,5},{2,4}}; and now I want to make a point plot ...
0
votes
0answers
44 views

How to make Show work in Mathematica 10 Kernel

Wolfram Research says it no longer supports JavaGraphics in Mathmatica 10. This is very bad for people who prefer the Kernel to the FrontEnd. However, I am still able to get it to work. Show ...
0
votes
2answers
43 views

Table results within loops

I have the following code. ...
0
votes
1answer
26 views

Derivative inside a Series [closed]

I have a function defined by a sum, which I would like to differentiate. For example: ...
0
votes
0answers
55 views

How to filter my signal?

As you can see, my signal is superimposed by an other sinus which has a slightly longer frequency. I would like to filter this out. I think I can do the filtering process, but there is one step that I ...
-1
votes
1answer
46 views

How to assign variables to selected roots of a polynomial equation? [closed]

I have a polynomial equation like the below, and I want to assign variables to the roots that are not pure imaginary. How I can do this? ...
11
votes
3answers
1k views

Can Mathematica's random number generation be improved?

Performance on Random Number generation is intolerable. Whenever you need many deviates from the same distribution but with different parameters it takes forever. Here is a thread on Poisson ...
1
vote
2answers
61 views

Solving equations using algebra [duplicate]

Has anyone ever solved an equation for students using algebraic steps? For example, you start with the equation. 2x+3 = 5 Then you show subtracting 3 from both ...
2
votes
1answer
41 views

How do I change the size of an imported picture in an animation?

My code right now plots a function, and animates an image moving along the curve of the function. I want to reduce the size of the image for this animation but I can't figure out how. If I try to ...

15 30 50 per page