10
votes
6answers
259 views

Split according to List and apply rule

I have a list which looks some thing like this {a1, a2, a3, a4, a5, a6, a7, a8, a9, a10} Now I want to split it according to lengths ...
0
votes
0answers
3 views

NDeigensystem returns error due to mesh discretization when calculating vibrations of a cantilever

There was an transcription error in the code I provided in a previous post: NDeigensystem returns complex non-hermitian error for the calculation of vibrations of a cantilever This resulted in it ...
7
votes
5answers
195 views

Combinations of multiple matching patterns

I wonder if there is any nice way to combine DownValues (or any other suitable rule-/pattern-/function -based Mathematica construct) when multiple patterns match an expression. Let me explain what I ...
1
vote
1answer
15 views

How to draw a moving point with time?

I am new to Mathematica. Try to draw a point moving with time. Like at t=0, a point is at p1(coordinates are random numbers); at t=1, this point is at p2. And there is always ONE point on the graph. ...
0
votes
0answers
30 views

How to make image3d smaller? Is `ImageResolution` useful?

I want to make the output of Image3D much smaller. For example ...
36
votes
4answers
2k views

Compiling more functions that don't call MainEvaluate

I would like to use Compile with functions defined outside Compile. For example if I have the two basic functions ...
393
votes
15answers
88k views

Where can I find examples of good Mathematica programming practice?

I consider myself a pretty good Mathematica programmer, but I'm always looking out for ways to either improve my way of doing things in Mathematica, or to see if there's something nifty that I haven't ...
-1
votes
0answers
25 views

Creating Vector Field Plots for an Implicit Equation

I am having difficulty creating a vector field plot for the implicit equation Log[(2x-1)/(x-1)] == t (* Did your best to use Mathematica syntax *) Where ...
6
votes
1answer
117 views

What kind of Arnoldi method is used in Mathematica?

Can someone give me a bit more information about what mathematical method Mathematica is using, (preconditioner, filtering-restarting, deflation) in the Lanczos implementation when I input something ...
4
votes
0answers
39 views

Why is Random[ ] faster than RandomReal[ ]?

As of version 6, Random[] was superseded by RandomReal[ ] etc, but both still work perfectly well. Playing with some timing ...
9
votes
4answers
157 views

Evaluation of Alternatives

I recently stumbled upon a few examples that suggest patterns containing Alternatives do not evaluate for individual alternatives. For example: ...
3
votes
1answer
48 views

I want to compute the derivative of Black and Scholes option

Good evening to everybody, my question is about computing the derivative of a Black and Scholes option and to draw it. My code is ...
4
votes
3answers
46 views

How to define a complicated function inside the body of Compile?

I want to compile a function in a way to keep its memory footprint down. In the example below, I am trying to compile a function f that makes three calls to ...
1
vote
1answer
79 views

How do I plot a ribbon in Mathematica?

I know mathematica has a built in tube function, but I want to be able to change the parameters of a ribbon and visualize that. Is this possible? How do I do this?
0
votes
0answers
33 views

Why doesn't mathematica evaluate the cells?

I have the following code in mathematica. Everything was ok and I was simplifying but suddenly mathematica crashed and after that it seems that it doesn't evaluate the functions. ...
5
votes
2answers
44 views

Why ParallelEvaluate[x = 0; {$KernelID, Dynamic[x]}] returns {{1,x},{2,x}}?

I'd expect that ParallelEvaluate[x = 0; {$KernelID, Dynamic[x]}] returns {{1, 0}, {2, 0}}, and that if in a parallel ...
0
votes
0answers
29 views

Unable to plot higher order polynomial equation using NSolve and contourplot

I have a polynomial equation in 'a,b' and I am trying to plot a curve between 'a' and 'b'. Both NSolve and ContourPlot works well upto 'a=15' , but after that the plot has scattered points. Is this ...
0
votes
1answer
42 views

how to generate a 3d graph of HCP crystal structure [duplicate]

I am confused with lattice parameter and the basis. The structure I generated is not HCP. To verify this, one could use this plotting function from the answer to Can a LatticeData image be displayed ...
0
votes
0answers
16 views

MatrixForm in Mathematica [duplicate]

I wanted to do subtractions between to matrices and I did the following ...
9
votes
1answer
105 views

Is equation numbering in exported HTML considered deprecated for built in stylesheets?

TLDR or simply stated: how do I export equation/section numbers to HTML? The built-in function doesn't seem to do it. Longer form of the question: So I've been tinkering around with the built in ...
11
votes
5answers
236 views

How to extract a contour line (or a region) from a ContourPlot?

Given a ContourPlot with a set of contours, say, this: is it possible to get the contours separating domains with the different colors in the form of lists? ...
0
votes
0answers
20 views

how to plot many curves for different values of a certain parameter [on hold]

how to plot many curves for different values of a certain parameter of a function? how to plot many curves for different values of a certain parameter of a function? i.e. i need to get one figure ...
2
votes
1answer
47 views

How to get the analytical solution of this equation set

There is a equation set: {2 x^2 + 49 - 7 x - 2 x Sqrt[x^2 + 49 - 7 x] Cos[rad] == (7 - x)^2, 2 x^2 + 49 - 7 x - 2 x Sqrt[x^2 + 49 - 7 x] Cos[rad + Pi/3] == 49} ...
1
vote
2answers
38 views

Manipulate slider freeze, and empty value in box

Here's a MWE code to show two problems I'm experiencing with the sliders and their value box, under Manipulate : ...
2
votes
1answer
118 views

Manipulations with options

I have two functions with options, for example f and g ...
4
votes
1answer
72 views

Why a part of this expression, similar to another, is left unchanged?

An expression has one of its part replaceable and one, strictly similar, that isn't. Please, can you point at the difference ? I can't pinpoint the complication ... The FullForm of ...
2
votes
1answer
55 views

Is there a bug of InverseDistanceTransform?

This is a example of documentation about InverseDistanceTransform. But this is my picture But it doesn't work: ...
1
vote
1answer
41 views

NIntegrate::inumri: error [on hold]

I am getting the following error: NIntegrate::inumri: The integrand c (1-0.6 (1-(1+Times[<<2>>])^0.5)-0.4 (1- (1+Times[<<2>>])^0.5)) (1-0.6 (1-(1+Times[<<2>>])^0.5)-0.4 (1- ...
0
votes
1answer
48 views

NumberForm pesky warning from Manipulate

I'm using the NumberForm command inside a Manipulate environment, and in some special cases Mathematica gives a pesky and mostly useless warning message : NumberForm::sigz: In addition to the ...
1
vote
1answer
66 views

Estimating error in NDSolve

I would like to give a theoretical estimation of local truncation error (and then for the global one) for a solution to a numerical initial value problem by ...
2
votes
1answer
45 views

Problems with QueueingNetworkProcess [on hold]

I have a two stage queueing network and want to vary the number of servers at the second node. The input data and the Manipulate command is below: ...
2
votes
1answer
222 views

Existence of an analytical form for integral

Can the following integration be performed with an analytical output? ...
0
votes
1answer
42 views

How to make an empty list inside a module program? It consatly spews errors [duplicate]

Okay, so, I'm trying to write a program within the module. It goes like this: create empty list, join it with a sample from a certain set called MyList, and then repeat it certain number of times. ...
11
votes
2answers
232 views

Partitioning a list when the cumulative sum exceeds 1

I have a long list of say 1 million Uniform(0,1) random numbers, such as: dat = {0.71, 0.685, 0.16, 0.82, 0.73, 0.44, 0.89, 0.02, 0.47, 0.65} I want to ...
3
votes
2answers
68 views

MeshRefinementFunction missing points

I'm doing some FEM on a rectangular region with a spherical cavity: ...
11
votes
6answers
933 views

How to set precision and format labeled Slider in Manipulate?

For my calculations, I need increased precision of parameter k in my Manipulate: ...
6
votes
5answers
146 views

How to generate two group of $n$ random numbers in $U(0,1)$ such that sum of these two groups equal? [on hold]

I want to have two groups of $n$ random numbers $u_i$ and $v_i$ in $U(0,1)$, such that $\sum u_i = \sum v_i$ What I tried is: I can firstly get $u_i$ by ...
4
votes
3answers
150 views

Graph generation from a non-paired edge list

The elements in e = {{6414, 6598, 6927}, {7, 1035, 2382, 6927}, …} are the graph nodes; for example, {6414,6598,6927} is ...
2
votes
0answers
18 views

weird behaviour of Listable fortran Librarylink function: different result each evaluation

I am working with fotran librarylink function currently. In this post, I will show some weird result of Listable fortran librarylink generated by intel compiler under windows (I tried gcc on linux the ...
-2
votes
0answers
43 views

NDeigensystem returns complex non-hermitian error for the calculation of vibrations of a cantilever [duplicate]

We are trying to use NDEigensystem to solve for the vibration of a cantilever with a triangular cross-section. The relevant PDE is $\mu \nabla^2 \vec u + (\lambda + \mu) \nabla(\nabla \cdot \vec u) = ...
0
votes
1answer
59 views

what do those signs #1, #1^2, #1^3, & mean here? [duplicate]

I have read common pitfalls page and the documentation page but I still don't understand what do those signs mean here? ...
3
votes
0answers
41 views

Weird behaviour for a vector InterpolatingFunction inside an NDSolve

I have run into some weird behaviour on the part of NDSolve which I find pretty bizarre and which I would like to understand better. Suppose, for the sake of ...
0
votes
0answers
17 views

Private Style in a StyleSheet with preformatted text

I want to create a new Style in my private StyleSheet. I duplicated the Style "Text" and made some alterations. Now I want that a Cell with this style has an expression already filled in, for example ...
6
votes
2answers
843 views

How to create a histogram of annual events, such as cherry blossom time

I have calculated blooming and ripening times for a specific variety of plant, based on actual temperature data from over 40 years. I would like to create two histograms on a single axis; one for ...
0
votes
0answers
65 views

Phase space of a system of differential equation

I have a system of three Coupled nonlinear equation of a physical system and i would like to plot the phase space. My system is a chaotic system dependant of three variable dependant of time (l1, ...
2
votes
0answers
29 views

Generation of Space Representation of non-crystallographic Point Groups

In Mathematica the command FiniteGroupData[{"CrystallographicPointGroup",<group number>}, "SpaceRepresentation"] yields the space representation ...
0
votes
2answers
179 views

Using different colors in TreeForm?

I've used TreeForm, and I appreciate that the syntax is fairly short, especially in comparison with TreeGraph. Is it possible ...
2
votes
0answers
24 views

WhenEvent and Resetting of Variable in PDE when operation succeeds

I have had success in using WhenEvent to reset or change a variable within NDSolve with ordinary differential equations. My ...
4
votes
1answer
78 views

System of equations is solved by NDSolve over just a tiny domain

I'm solving numerically a system of differential equations with the use of NDSolve. The numerical integration works only a very small interval of the argument. I'm ...

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