2
votes
3answers
196 views

How does one unpack the contents of a list while using rules to substitute values for each variable?

My intention is having a large collection of variables (symbols to be more specific) in a list and substituting all the variables at once with a value using rule instead of going through each one, one ...
2
votes
1answer
185 views

Fraction shortcut not working, giving strange spacing character on german keyboard

So usually when you want to enter a fraction in Mathematica, you can do so by pressing "Ctrl+/". If you are on laptop with a german keyboard however, you will have to press "Ctrl+Shift+/" since you ...
5
votes
1answer
128 views

SQLInsert'ing Null into a table (not SQLite)

Is it possible to insert Null values using DatabaseLink, without formatting the query string manually? Hans found (below) that this works for SQLite, so it appears ...
2
votes
0answers
98 views

Shadowing issue with DeleteDuplicatesBy

I have been running a function in Mathematica 10 with the command, DeleteDuplicatesBy. The function was working great until one day I started to get an error with ...
3
votes
2answers
148 views

Estimate parameters of AR1 process

I am trying to estimate the parameters of a series $Z_t=W_t^\beta$, where W_t follows an AR1 process with mean 2, $\rho=0.9$ and $\sigma=0.1$: $W_t = \rho W_{t-1} + (1-\rho) \bar{W} + \epsilon_t$ ...
1
vote
1answer
107 views
2
votes
1answer
173 views

Why does FindFit work and NonlinearModelFit does not?

I have a somewhat complicated function that I have defined. ...
0
votes
1answer
70 views

NDSolve does not satisfy initial conditions

For the problem I'm facing, I have three coupled diff eqns that I'm trying to solve ...
0
votes
2answers
253 views

How to solve a pair of coupled 2nd order equations using shooting method

I have a pair of equations for x[t] and y[t]. Both are 2nd order and they are coupled. Now say that I know the following ...
1
vote
1answer
123 views

Can't get rid of vertical background color

I am trying to use GraphicsGrid, the background option is set to white, as well as for the separate graphs. But there are still grey stripes. What is the reason for ...
0
votes
0answers
68 views

Equations in a quadratic field

I would like to solve a system of equations in a quadratic field, meaning that each variable $x$ of my system can be written $a + b \sqrt{d}$, where $d$ is a fixed value. Suppose for example that I ...
2
votes
0answers
97 views

Nasty integral advice

I have a pretty ferocious integral to solve, and since it doesn't seem I'll be able to do much analytically, I've taken to Mathematica to get some information. Mainly, I want to see if there are any ...
2
votes
1answer
101 views

Help plot with horizontal filling

I want to plot a graph that looks like the following, where the blue curve is $y=x^2$ and the red lines are $y=8x-12$ and $y=-8x+20$. The filling is applied horizontally from the lines to the edge of ...
1
vote
1answer
61 views

Can list interpolation be made listable? [closed]

I have 8 sets of 2D-data that I want to each interpolate with ListInterpolate, because it is a very efficient command. The complete data are therefore in a 3D table....
3
votes
2answers
117 views

AxesLabel style like in FrameLabel [closed]

I would like to use ListPlot without Frame. But AxesLabel produces y-label above the y-axis ...
12
votes
3answers
285 views

Inverse of Interpreter[“Color”]: Convert a RGBColor to a natural language color name

What is the best way to create the inverse function of Interpreter["Color"]? That function takes a natural language color name like ...
0
votes
2answers
535 views

How to plot an ellipsoid from an implicit equation [duplicate]

I need a way to plot a generic ellipsoid given the following implicit equation. Can someone help me? $$\frac{x^2}{a^2}+\frac{y^2}{b^2}+\frac{z^2}{c^2}=1$$
2
votes
1answer
63 views

How do I center an item in a Grid?

I was trying to use Grid to align different plots, two on the first row, and only one in the second row, so I have something like this (where a,b and c are plots): ...
6
votes
1answer
166 views

Using Padding with Text and Style

Suppose that I use: Text[Style["(1, 0, 0)", 12, Background -> White], {1, 1, 0}] How can I put a few points of padding around the text? Thanks to Jens: ...
0
votes
1answer
86 views

Using Simplify to perform substitutions [closed]

I have a matrix element $k_x$ and I want to substitute it as $-i\kappa$, I tried ...
2
votes
0answers
79 views

How to increase font size in front-end UI Menus [closed]

Is it possible to increase the font size in the notebook GUI's menus, messages window, help windows, etc?
0
votes
0answers
41 views

Boundary condition [duplicate]

I'm having the following issue that can not find a solution , by using this boundary condition v[0, t] == u[1, t] that Mathematica does not understand, someone ...
1
vote
1answer
48 views

Construct a button to start a routine [duplicate]

When executing Button ["Print" Print[1]] you get a button that, if pressed, prints to the screen 1. What I would like to have is ...
1
vote
1answer
61 views

Unexpected AdjacencyMatrix output [duplicate]

I have a directed graph with this Edgelist defined as follow: ...
3
votes
1answer
172 views

Get the creation time of a file

Windows is able to tell me when (date & time) a file in the file system was created or altered. Is it possible to get such information in Mathematica, e.g., get the creation time of a text file ...
3
votes
1answer
52 views

How to enter options when using an input palette

Integrate[1/(x^2 + y^2 + z^2)^(5/2), {x, 0, b}, {y, 0, l}, GenerateConditions -> False] We can type in the above expression easily. But if someone new to ...
0
votes
1answer
193 views

Improving NDSolve computation speed for 3D stationary PDE

Continuing my last question, I am trying to solve 3D Schrodinger equation (with mass equals to 1) and with no potential (I will add a potential later). The analytical solution for this equation is ...
2
votes
1answer
86 views

creating a stacked function that returns the multi varibles

I'm a beginner in Mathematica with little programming background but I'm determined to learn this. I'm trying to make a function that calculates two variables r2 &...
2
votes
1answer
147 views

Equal flow boundary conditions

I'm having the following issue that can not find a solution , by using this boundary condition v[0, t] == u[1, t] that Mathematica does not understand, someone ...
2
votes
1answer
124 views

Defining symbolic expectation function

I want to define the standard expectation $E$ operator in Mathematica. In particular, I want it to satisfy, $E[ c + a \cdot X_1^{n_1} X_2^{n_2} X_3^{n_3} X_4^{n_4} + b \cdot Y_1^{m_1} Y_2^{m_2} Y_3^...
0
votes
1answer
47 views

Could I use Select with condition on any column other than First (Last)? [closed]

I often deal with huge tables of various functions of randomly generated values for my research. Sometimes there's need to only keep rows which satisfy a specific condition. This is easy with ...
0
votes
0answers
74 views

How to export graphics for Blend4Web [duplicate]

Mathematica Online is not helpful in deploying 3D graphics on your website. But a new sdk Blend4Web looks promising. Does anyone know a way to export textured graphics into the Blender engine?
3
votes
2answers
256 views

How can I capture a rectangular area from an image?

I am looking for a method to extract rectangular areas from an image. The image is divided up into rectangular problem spaces like the image shown below. Each numbered problem is given with some text ...
3
votes
1answer
129 views

Computing planet conjunctions with 2D circular orbits still hard?

All methods I've seen for computing planetary/stellar conjuctions (when two planets or a planet and a star appear close together in the sky because their angular separation, as measured from Earth, ...
1
vote
1answer
77 views

Defining Probability Distribution with parameters

I have a family of probability distributions, indexed by elements in $\mathcal I =\mathbb N \times [0,1] \times [0,1]$. For each $(A,B,C) \in \mathcal I$ I know how to define the corresponding ...
4
votes
2answers
256 views

Determine the coefficient of expansion of the product of two sumations?

I would like to determine the coefficient of a desired term in the product of two summation where the powers of $x$ are not necessarily integers. For example $$ \sum_{i=1}^N x^{1/i}\sum_{j=1}^N x^{1/j}...
6
votes
2answers
144 views

Plot of The RiemannSiegelZ Function

I would appreciate your help to visualize the of the following function RiemannSiegelZ[x] with this range. { 18154980120849865 , 18154980120849885 } I tried this: ...
2
votes
1answer
81 views

Use slider controls to set function domain of plotted function

I want to display Plot[f,{t, t1, t2}] in a Manipulate with the domain {t1, t2} specified by ...
3
votes
1answer
126 views

High precision calculation of infinite product involving prime numbers

I'm recently studying some topics in analytic number theory and I have encountered results involving the infinite product $$C=\prod_{p}\left(1-\frac{1}{p(p+1)}\right)$$ where $p$ denotes calculating ...
2
votes
2answers
186 views

The Chart of Matrix Eigenvalues : Energy Levels

There is the possibility that this question may have been asked previously, but as we are unfamiliar with the nature of the chart below, we hope to seek a response to this query. Consider a matrix as ...
0
votes
1answer
56 views

Sum of hypergeometric functions, variable number of arguments

How can I write in Mathematica an expression like this? $$\sum_{k=1}^n {_{k}F_{k}} (1,1,\dots,1; \,2,2,\dots,2; \,z) ~,$$ where ${_{p}F_{q}}$ is the generalized hypergeometric function. My problem ...
7
votes
1answer
197 views

Why the BandpassFilter is different than applying LowpassFilter then HighpassFilter

If I generate some data with noise, and use a filter to filter the noise, why does BandpassFilter not produce the same results as using ...
7
votes
2answers
239 views

Extending NDSolve beyond a singularity

The $\tan$ function satisfies the following IVP: $$y'=1+y^2 ,\quad y(0)=0 $$ and has simple poles at the points $x=\pi/2+ \pi n$ for integer $n$. When trying to get $\tan$ via numerical integration,...
2
votes
1answer
310 views

How to evaluate this integral?

Why can it not evaluate this integral? Please help. Integrate[Exp[-r^2]* r^2*Log[Exp[-r^2]* r^2*(2.5 - r^2)*(2.5 - r^2)], {r, 0, 10}]
1
vote
1answer
80 views

How to Minimize a Log/Linear function symbolically?

I have my objective function as : $\hspace{25mm} \text{Minimize} \sum_k- \alpha_k \log_2 W_k$ $\hspace{25mm} \text{subject to}: 0\leq W_k \leq q', 0 \leq \alpha_k \leq 1 $ $\hspace{25mm} k =0,...
-1
votes
1answer
152 views

What am I doing wrong when using Solve ( Wolfram Alpha)

It is not because we do not interpreted correctly WolframAlpha["Solve[64(!(*FractionBox[(x - *SqrtBox[(*SuperscriptBox[(x), \ (2)] - 1)]), (x + 1)]) !(*SuperscriptBox[()), \ (2)])-25(1-!(*FractionBox[...
2
votes
2answers
83 views

How-to let user define a set of VertexCoordinates in a Graph

Here is a simple code I wrote to visualize what I am trying to achieve: C.1 ...
12
votes
1answer
231 views

Nearest Kronecker Product

Some people (see The ubiquitous Kronecker product by Van Loan) have worked on finding two matrices $\mathbf A$,$\mathbf B$ of specified size whose tensor product $\mathbf A\otimes\mathbf B$ is closest ...
4
votes
1answer
95 views

Mathematica 10 Audio Export Issue

Summary of the problem: When exporting data as an audio file (AIFF/WAV etc.), there appears to be unwanted scaling and offset in the data such that the minimum and maximum values are forced to be -1 ...
3
votes
1answer
63 views

BarPlot3D box inclusion of Graphics3D primitives

My final goal is to get coordinate grid on the z=0 plane of BarChart3D. The provided FaceGrid...

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