0
votes
1answer
113 views

How to draw a picture like this?

That is what l want,but l can only use Show,Plot3D to get something just like this What should l do?Thanks~
11
votes
1answer
352 views

Does NRoots own an abstract counterpart? If not, can we write one?

We know when solving linear algebra equations, despite its abstract syntax, LinearSolve is much faster compared to Solve: ...
1
vote
1answer
58 views

Searching if a directory exists within a folder

I hope this question is not a duplicate, but I could not find any other question which answered my specific question, which is: I have the following folder structure (just an example): samefolder/...
-1
votes
1answer
155 views

Small mismatch in theoretical vs MMA solutions of a damped harmonic oscillator differential equation

I solved the differential equation $$ \ddot y + 0.43 \dot y + y =0.1 \cos(2x), \quad y(0)=1,\ \dot y(0)=1 \quad(0) $$ using both the theoretical results from wikipedia and using MMA (I also tested ...
3
votes
3answers
498 views

How to solve the equation $A \sin x + B \cos x = 0$ for all $x$?

I have the equation: $A \sin x + B \cos[x] = 0$ that should be satisfied for all the $x$. Of course, the solution is obvious: $A=B=0$, but I need Mathematica to resolve it automatically because this ...
7
votes
5answers
748 views

Calculating weird numbers

A weird number is a number such that the sum of the proper divisors (divisors including 1 but not itself) of the number is greater than the number, but no subset of these divisors sums to to ...
1
vote
1answer
416 views

Trying to calculate derivatives of spherical harmonics

I am trying to confirm what is shown on this website: http://functions.wolfram.com/Polynomials/SphericalHarmonicY/20/01/01/0001/ But when I type ...
5
votes
2answers
163 views

Indexed Thread on dataset and list

I currently have a dataset, and I would like to add a column based on another list. For example: ...
2
votes
2answers
69 views

How to edit a list according to the other list? [duplicate]

Gday guys. This problem troubles me, and I hope you can help me solve it. Say I have two random lists L1={{2},{5},{1},{0},{4},{7},{8}} L2={2,5,1,0,4,7,8} and ...
3
votes
1answer
83 views

Correct interpretation of /. (ReplaceAll)

Consider that you have a complicated expression, which is expensive in terms of running time and memory, and depends on some (initial) parameters. You want to test it for some simple values of the ...
8
votes
5answers
1k views

How I calculate the volume of multiple intersecting spheres?

I would like to know how to calculate the volume of the union of multiple possibly intersecting spheres (using Sphere[]). Please see the figure: I was trying to get a mesh/delaunayMesh out of the ...
6
votes
5answers
179 views

Setting value of a rule

How do I change the value of a rule? For example, If I have a = x->3, how do I reset the value of x/.a to 4, so that ...
1
vote
1answer
50 views

Mathematica defines a function as list

This might be a very silly question but i'm defining a function as: \[Chi][AR_] := ((AR^(2) - 1)/(AR^(2) + 1)); which is clearly a scalar function of AR; however ...
4
votes
3answers
126 views

position of rows (or columns) whose elements all satisfy a condition

How do I determine the position of rows whose entries all satisfy some condition (e.g., all elements of the row are positive)? I've found out how to use Select to ...
3
votes
2answers
217 views

How to use select and map together

I have two lists, list1 and list2. I want to Select from ...
4
votes
0answers
103 views

Is there a convenient way to sum TimeSeries objects in Mathematica?

Imagine I have two TimeSeries objects, ...
2
votes
1answer
128 views

Can you explain how the remote kernel work

I have use remote kernel almost every day, but I guess I never understand how it works. I have basically two questions: How do we manually setup and use one kernel as a remote kernel to the other? ...
0
votes
2answers
233 views

Why won't this graph? [closed]

I'm trying to sketch level curve for z=k for the specified values of k={-2,-1,2} of z= 4x^2 - 4x + y^2 + 2y So I changed this(...
3
votes
1answer
137 views

HSQLDB database webserver access

I need a database that runs its connection over http and not tcpip. The "HSQLDB (webserver)" jdbc driver should be able to do just that. The following code launces the webserver but the OpenSQLConnect ...
2
votes
1answer
86 views

Can I define a “total Curl” operator similar to a “total derivative (Dt)” operator? [duplicate]

I am trying to take the curl of a vector field. A={A1,A2,A3} B=Curl[A,{x,y,z}] This yields {0,0,0} because Mathematica ...
13
votes
1answer
283 views

Possible bug: Quantity[2,“meters”] returns 2 None meters

Bug introduced in version 10 or earlier and fixed in version 10.0.2 I'm using 10.0 for Linux. Trial 1: Quantity[2,"meters"] 2 None meters Trial 2: ...
2
votes
2answers
197 views

How do I get all the roots within a certain range for an equation? [duplicate]

I wish to find ALL the roots of the following equation $ x \tan(ax) - c = 0$ within a range, where a and c are constants I control. I've been using ...
2
votes
1answer
173 views

StreamPlot of a square-root - Issue

When I plot ...
2
votes
1answer
93 views

Export as Table with alignment?

I have a table in Mathematica as a list of lists. How to export the table, and force Mathematica to insert as many spaces as needed between columns so that columns are aligned? For example, ...
1
vote
1answer
242 views

NSolve fails to solve a nonlinear equation

Mathematica can not solve this: g = 9.82; ω = 0.5; h = 5; y0 = 1; v = 0; τ = 0; NSolve[h + v t - (g t^2)/2 == y0 Sin[ω t], t]; The error code is: NSolve::...
1
vote
1answer
69 views

BarLegend rasterized in EMF and EPS export

A while ago you guys gave me a splendid workaround to the rasterization bug in exported BarCharts. Now I noticed that the workaround is not working for BarLegends. My problem is, that ...
5
votes
1answer
144 views

Integrate over implicit 1D region: works for algebraic but not transcendental equation?

QUESTION How come this works: NIntegrate[1, {x, y} ∈ ImplicitRegion[{x == y^3, x <= 1, x >= 0}, {x, y}]] But this fails: ...
10
votes
2answers
210 views

Convert recursive RegularExpression to StringExpression?

Consider the following expression for matching balanced brackets: ...
2
votes
1answer
220 views

Export generated mesh

Say I have generated a mesh using ToElementMesh, following one of the examples here: http://reference.wolfram.com/language/FEMDocumentation/ref/ToElementMesh.html ...
1
vote
1answer
206 views

NSolve on bounded domain

I don't expect NSolve[] to be able to obtain all solutions in generalfor example. In principle there should be an algorithm that finds all solution to $f(x)=0$ for $...
1
vote
1answer
65 views

Transform List from {a,a,b,b,b,c} to {{a,2},{b,3},{c,1}} [closed]

The title pretty much says it. I want to map over the solutions returned by Solve but want to avoid calculating the same thing over and over again. e.g. ...
3
votes
1answer
182 views

Automatically zoom-out on ListPlot?

Mathematica chooses the PlotRange for a ListPlot such that the lowest x-value lies on the y-axis and vice versa. Because of this these points often are difficult to find. I could increase the dot size,...
3
votes
1answer
209 views

Meshing of a cube

I want to mesh a cube and what I use is ToElementMesh[Cuboid[ {-1, -1, -1}, {1, 1, 1}]]. This creates a regular grid of the cube. Is there a way to specify that ...
5
votes
0answers
312 views

Packages for Semidefinite programming

This question has already been asked here. I am not sure, whether I should have asked this question as a comment of an old question or in the general programming forum of stackexchange. Moderators ...
8
votes
1answer
221 views

Numerical Integration different in Mathematica version 9 and 10 with same options

I have noted that the same function with the same settings gives me different results in Mathematica version 9 and 10. This involves integrating numerically interpolating functions and so on. Here a ...
0
votes
1answer
244 views

Manipulate of graphics + ParametricPlot [duplicate]

Edited at bottom - I think the problem is my unwise expectation to overlay Plot___ over Graphics objects and magically have them scale. I have an entry-level manipulate that shows how a cycloid is ...
0
votes
2answers
62 views

import string to data

...
10
votes
1answer
2k views

How best to embed various cell groups into a $\LaTeX$ project?

I'm an author and a coder. I want to reference various parts of my notebooks in my $\LaTeX$ project. I've tried doing the following, using a post on the $\LaTeX$ side of this problem. I'd like to ...
3
votes
1answer
142 views

Creating an autokey cipher function

Can someone help me with putting what I can say in words into code. I want to create autokey encrypt and decrypt functions (just wanting help encrypting and then can figure out decrypting). Everything ...
0
votes
1answer
92 views

How to solve this equation? or get the numbers of solutions of the function?

I have a function like this.. $$ f[k]=\int_0^\infty Exp[-ax]x(Cos[bx])^{2}BesslJ[0,kx]dx $$ I want to know how many local maximuns this function has.. So I try to get the derivative of f[k] $$ g[k]=D[...
-1
votes
1answer
98 views

Black Ovals appeared in my Mathematica notebook [duplicate]

I copied and pasted something from another Mathematic notebook and started getting the same black ovals seen in this question: Colored marks appearing in notebook input text? The suggestion to turn ...
3
votes
0answers
92 views

Is there a documentation generator for Mathematica?

I'm looking for a way to document the functions of my packages inline, preferably inside comments. There should be a Doxygen type tool for this that takes comments and that generates html from markup ...
1
vote
0answers
31 views

Changing cell style in V10.0.2 [duplicate]

In Mathematica 10.0.0 and 10.0.1 I used to change cell style by putting the cursor anywhere in the cell and then invoking one the short cuts (Alt + 1, 2, 3, 4, 5, 6, 7, 8, 9) to change cell style ...
5
votes
1answer
195 views

How to move a cell up or down with a keystroke?

It is very useful during refactoring to move lines around. All popular IDEs or text editors have this feature (PyCharm, Vim, Sublime, etc..) for example in Xcode you press: ⌥⌘[ or ⌥⌘] to move lines up ...
1
vote
2answers
102 views

Does FindFit use symbolic differentiation?

Does FindFit use symbolic differentiation when optimizing by least squares a non-linear function?
0
votes
0answers
57 views

How to import (from a table file) only rows with a specific element in a given position using Import?

I have a large file containing a table. To be specific, the table columns are aligned by spaces, and the rows are terminated by newlines. I want to import only specific rows from this table. For ...
1
vote
0answers
30 views

How to specify alignment of columns when exporting a table using Export, and how to use spaces instead of tabs?

I have a table in list representation. How can I export it, specifying that some columns must be right-aligned and others left-aligned? Morevoer, columns should be space-separated (with an appropriate ...
1
vote
1answer
90 views

How to list indices of list elements that meet a condition? [closed]

Is there a tidy way to create a list of the indices of elements of a list that meet specified conditions? This method gets the job done, but it's clumsy and not conducive to nesting: ...
2
votes
1answer
185 views

StreamPlot segmented lines

I am plotting this vector field: ...
0
votes
2answers
125 views

Derivative after numerical Integration

So I have a function that I want to numerically integrate with respect to temperature, so the integral changes depending on the value of temperature being used as it is one of the bounds. After ...

15 30 50 per page