0
votes
0answers
2 views

Freeing memory after file Import

This problem that I would like to resolve is how to free memory used Import a file when the file is no longer in use. I have a project in which I need to read and analyze a large number of .json ...
-3
votes
0answers
17 views

How can I fix this hole?

What I did and what I got: What I want: no hole i.e. a closed end cap. I guess the hole is related to the "invalid comparison" but this alert is undocumented AFAICS. Note: I am using WPC only.
1
vote
0answers
14 views

How can I avoid these defects in ContourPlot3D output on WPC?

Evidently not by increasing PlotPoints: I have read https://reference.wolfram.com/language/tutorial/ArbitraryPrecisionNumbers.html "If you give higher‐precision input, the Wolfram Language will ...
0
votes
1answer
24 views

Rotate with Euler angles in Graphics3D

I need to rotate with the Euler angle sequence: Yaw by $\psi$ around $z$ Pitch by $\theta$ around $y'$ Roll by $\phi$ around $x''$ I know of Rotate[] in ...
4
votes
2answers
58 views

How to clear everything in Mathematica?

I am a new user. According to a documentation, Clear["context`*"] clears all symbols in a particular context. I want to clear everything (functions, variables, etc..) After I use the above command, ...
1
vote
1answer
61 views

Saving file as .m causes it to save as comments

I am attempting to create a Package and so am saving a notebook with the code from Mathematica's example ...
0
votes
1answer
30 views

Dynamic programming: Fibonacci generator

I have the following piece of code: ...
0
votes
0answers
30 views

How to inscribe a circular helix in a cylinder?

I need a way to plot a circular helix in a cylinder on Wolfram Mathematica. Someone can help me?
0
votes
0answers
13 views

Issue with Differentiation over a tensor

I am new user in Mathematica. I am working with liquid crystal theory, and one of the notation there is the tensor: $ \Pi_{ij} = \frac {\partial {F_{el}}} { \partial ( \partial {n_i} / \partial { ...
0
votes
0answers
9 views

OrientDB JDBC OpenSQLConnection : Execution of SQL failed

I am testing JDBC connection of OrientDB v2.0.13 from Wolfram Language. ...
1
vote
1answer
24 views

Is there a way for accuracy backtick notation to accept variable inputs?

Backtick notation uses 1.0``20 to give 1 with 20 places of accuracy after the decimal point. But what I want is ...
3
votes
0answers
41 views

Cannot Block Plus

It is customary to use the following idiom to partially evaluate something inside a held expression: ...
-3
votes
0answers
17 views

How does $1\rightarrow A\rightarrow B\rightarrow C\rightarrow 1$ imply that $Im(f:B\rightarrow C)\cong B/A$? [on hold]

From a lot of SE answers and also web forums, in a short exact sequence, people say the injective property from A to B and surjective property from B to C clearly implies the image of the function is ...
1
vote
2answers
62 views
0
votes
0answers
15 views

Transform a vector DE into a set of scalar DEs

I have the vector equality: {{a,b},{c,d}}.D[{x1[t],x2[t]},t]=={{e,f},{g,h}}.{u1[t],u2[t]} I want to solve this using DSolve. ...
4
votes
0answers
57 views

Dipolar magnetic field lines inside a cylinder

I'm drawing the magnetic field lines of a rotating dipole (magnetic field distorded by emission of radiation). Currently, my Mathematica 7.0 code is fully working, but I'm having a constraint which I ...
2
votes
0answers
36 views

Suggestions for solving a large linear system

I have a system of $\approx 200,000$ linear equations in $\approx 40,000$ variables (with rational coefficients) and I would like to determine the dimension of the solution space, which I know to be ...
3
votes
1answer
40 views

In a PDE solution let us integrate out one of two coordinates

Here is a trapezoid within which I am solving a simple Laplace equation with the Dirichlet boundary conditions set at its top and bottom: ...
-5
votes
1answer
35 views

create a table via menu-

I created a table via menu 3x3 , but I cannot add afterwards a new line or column, the tool doesn't add a row of 3 columns but a row of one column at the end ... adding a new column, adds at the end ...
3
votes
1answer
33 views

Saving Dot-ed eigenvectors in a special comparison

We have produced a 4*4 matrix in any iteration containing nx from 0 to 2 by steps of 0.5. and in any iteration we have saved sorted orthogonalized-eigenvectors based on their eigenvalues with this ...
-1
votes
0answers
42 views

ParametricPlot3D produces no output [on hold]

When I try to run the code I show below, it doesn't plot anything. I guess ParametricPlot3D doesn't understand the functions that I defined. How can I deal with ...
0
votes
2answers
53 views

How to draw multiple cuboids on the same plot

I have defined a table ...
2
votes
0answers
41 views

Fast Partition of list at depth 2

I am looking to partition a list up at a certain depth level. Following code should demonstrate what I mean: ...
0
votes
1answer
20 views
0
votes
1answer
42 views

More issues Integrate, NIntegrate, FindRoot

I'm trying to solve a system of 3 non-linear equations using FindRoot and Integrate. If I start FindRoot[] close to the right answer, it works well but returns a bunch of error messages first. ...
0
votes
1answer
42 views

Problem with solving coupled differential equations

The following code seem to produce an output that appears to be independent of the parameter "fg". It is possible that the way the code is written might be causing it, but how can one fix this ...
0
votes
1answer
25 views

How to pick max/mins of elements that match patterns?

I have a list of complicated expressions that involve indexed coefficients. For example: expr={m[5],c[3]*m[1]^2+m[2],Sqrt[m[2]+3*m[3]*c[8],foo[m[3]*m[5]]}; How ...
3
votes
1answer
150 views

Using Probability for n-gram string queries

I want to use Probability to ask questions on strings like "what's the probability of the occurrence of the trigram 'the' conditioned on the occurence of the digram 'th'?" This doesn't work. I ...
1
vote
0answers
97 views

MatrixExp of a complex matrix of size about 10000 by 10000 [on hold]

I want to apply MatrixExp of a numerical, complex matrix of size about 10000 by 10000, and I also need high precision as I need to multiply several such matrices. ...
1
vote
1answer
45 views

Differentiation inside package

I am trying to put all my functions in a single package and some of them do not work because of differentiation. Suppose I have the following package ...
0
votes
0answers
39 views

Trying to find parameters for a system of inequalities

So I have a system of 4-dimensional system of ODEs and I'm trying to find any values of parameters that satisfy properties I need. In this picture, I want two basins of attraction, one of which the ...
0
votes
1answer
47 views

Colors on a 3D curve not working

I'm having troubles applying colors to a simple 3D curve plot. Here's the code : ...
1
vote
1answer
66 views

I keep writing functions like this one: subtract[{a_, b_}] := Subtract[a, b] [duplicate]

(Edited to provide an example) Recently I have found myself writing silly functions like the following, which is just a new arity of Subtract in which the arguments are inside a list. ...
0
votes
0answers
31 views

Real time solution of a DE with changing parameters [on hold]

I have a set of coupled differential equations (9 equations with 9 unknowns) and 9 known initial conditions to describe the motion of a quadcopter. Question: how can I make a real-time simulator out ...
2
votes
1answer
37 views

Associations - getting values according to a key pattern

I want to get all counts of trigrams that with "th" (or any other given digram). ...
1
vote
0answers
19 views

Selecting the parallel kernels where tasks can be executed

When I use ParallelSubmit, is it possible to select on which kernel a task can possibly be executed ? For example if have 3 parallel kernels, can I only use 2 of them so that one is remaining in case ...
3
votes
0answers
55 views

How to extract a Graph[] from an image?

This graph (as a picture) is given below: I am wondering rather than setting up this network graph using Mathematica syntax such as PathGraph,...
-1
votes
0answers
37 views

Gradient Help w/ Problem 1 [on hold]

​Go with f[x, y, z] = Log[3 x^2 + y^2 + z^2] In which direction should you leave the point {2.1, -3.7, 4.3} to get the ...
1
vote
1answer
35 views

How to define a number of infix operators with predefined relative precedences

Reading a number of questions about infix operator notations I want to ask if somebody could reimplement the problem below in a simpler way, say modifying ...
0
votes
0answers
20 views

Custom drop-down list of tags for Dataset Keys similar to CountryData

CountryData produces a drop-down list of tags when you enter a string. I would like to replicate this functionality for a ...
1
vote
2answers
86 views

Styling the edges of a graph according to the multiplicities of the edges

I used the following code to make a simple triangle, in which the nodes have different effects each other: ...
0
votes
0answers
42 views

Solving matrix optimization

I have the following problem. Let $X_1, X_2, \cdots, X_k$ are $n \times n$ Hermitian matrices (need not be positive) given. Let a $n \times n$ positive matrix $A$ is given such that $Tr(A.X_j)<0$ ...
1
vote
2answers
82 views

How to get the desired (equivalent) answer from Integrate?

This is the integrand: 1/beta/(2*z)/(1 - beta) // TraditionalForm Integrating with respect to z, gives ...
5
votes
2answers
119 views

Displaying a list of percentage values according to their classification

I have a list of percentages as follows: percent = {21.15, 42.3, 57.68, 73.06, 84.6, 90.37, 96.14, 99.99, 99.99, 99.99, 99.99} I want to classify these ...
0
votes
2answers
39 views

“Part specification is longer than depth” warning in Position function [duplicate]

I'm working on a project which analyzes financial data. I download the price and dividend information for the SPY ETF which tracks the S&P 500: ...
1
vote
1answer
69 views

Program to demonstrate rotation according to quaternion values

On the Wolfram|Alpha website, I type quaternion(1,1,1,1) into the search field. Wolfram|Alpha shows a 3D transformation of the quaternion values representing the orientation of an object. I have 9 ...
0
votes
0answers
57 views

Mathematica requirements management [on hold]

Is there a way to use Mathematica notebook as a requirements document as it's possible in IBM DOORS ? ...
4
votes
3answers
96 views

How to find points along the inner and outer edge of a ring along a specific direction

I have a set of random numbers distributed on a annular disk. I want to find points on the inner and outer edge along a particular angle. One possibility is to use ...
0
votes
1answer
39 views

Why can not the vector be transposed in integrating over a region? [duplicate]

Clear[x, A]; A = {{2, -1, 0}, {-1, 2, -1}, {0, -1, 1}}; Integrate[Exp[-x.A.{x}\[Transpose]/2], x \[Element] FullRegion[3]] This code raises an error ...
2
votes
0answers
19 views

Page breaks and headings in long table or grid

I have a need for long tables in a document I am producing but I am having difficulty. The printed document ends up with page breaks midway through the table which cuts rows part way through. I'd also ...

15 30 50 per page