18
votes
5answers
435 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 ...
0
votes
1answer
63 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? ...
0
votes
0answers
20 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 ...
4
votes
1answer
75 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 ...
1
vote
1answer
54 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- ...
3
votes
0answers
35 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 ...
0
votes
0answers
52 views

Fourier-style solutions to differential equations, not piecewise polynomials

NDSolve returns piecewise polynomials. Is there any way I can get a single (non piecewise) function consisting of sines and cosines instead? Sort of a "Fourier approximation" to the solution of my ...
10
votes
1answer
151 views

Plot of $sin(x^x)$ is missing from $x=143$

When plotting the graph of $sin(x^x)$ I noticed that there is no plot from about $x=143$. I don't suppose there is a purely mathematical explanation for this? So, why is there no graph in ...
0
votes
0answers
75 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
1answer
65 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: ...
1
vote
0answers
69 views

Possible memory leak in FindMinimum? (MMA v10.0)

So I was running some code when I noticed Mathematica was gulping memory, and after some debugging I think the culprit is found. It turned out the function ...
2
votes
2answers
152 views

Symbolic vs numerical integration

This is related to a question that I asked before but didn't resolve quite well. I want to obtain the solution of the following expression analytically: ...
0
votes
0answers
32 views

File filter in SystemDialogInput

I want to write a SystemDialogInput function that allows user to choose a file from a directory. In the directory, there are two kinds of image files: Atom images: The name of the file is in the ...
4
votes
2answers
84 views

MeshRefinementFunction missing points

I'm doing some FEM on a rectangular region with a spherical cavity: ...
1
vote
1answer
57 views

How to refer a number in a list with two columns, first one is a number and the second one is empty? [on hold]

Let's say, I have defined a list as list = {{-31, -31}, {52, }, {34, -11}, {-38, }, {78, -44}, {-36,14}, {-9, 98}, {33, 6}, {82, 99}, {-85, -10}} As you can see, ...
12
votes
5answers
340 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? ...
1
vote
0answers
31 views

Changing from Cartesian to polar coordinates in partial differential equation [duplicate]

I have a partial differential equation: $$\left(x^2+y^2\right)\frac{{{\partial ^2}u(x,y)}}{{\partial {x^2}}} + x^2\frac{{{\partial ^2}u(x,y)}}{{\partial {y^2}}}=0$$ How to change from Cartesian to ...
7
votes
1answer
116 views

Add terms to nested list

Suppose I have a nested list of the following: list={{1,2},{5,8},{4,1}...} I would like to add a number to each first term of the list. The output would be ...
2
votes
1answer
89 views

Automatic text-wrapping in labels in `TimelinePlot`

Part-related to this question and part-related to this one, I would like to make use of the new features of TimelinePlot in 10.3, but would like to incorporate some ...
1
vote
1answer
27 views

Length in Compile encounter “type Integer encountered in assignment of Type Real ”

Compile[{}, Module[{n}, n = Length[{1, 2, 3, 4}]; n = n/2]] The above code will emit errors Compile::cset: Variable n of type _Integer encountered in ...
1
vote
1answer
55 views

ParallelTable should distribute dedicated evaluation range to different kernels

I have 4 kernels and would like that in ParallelTable: ...
-7
votes
0answers
39 views

Optimization (minimization) of equations with conditions [closed]

I need to minimize the expression a+(b/3) + c under the conditions: ...
-7
votes
2answers
60 views

How to solve for the eigenvalue in matrix? [closed]

For which value of $a$ in the matrix {{a,2}, {3,4}} has the matrix eigenvalue of $0$? How to solve it in Mathematica?
6
votes
4answers
195 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 ...
0
votes
1answer
24 views

Why can't I change the Magnification in Printout Style in Default.nb

This happens with Mathermatica 10.3.1.0: When working with a notebook, I can choose between different working environments. However, they inherit their settings from Default.nb situated at ...
-2
votes
0answers
44 views
1
vote
2answers
95 views
1
vote
2answers
65 views

intermediate steps of simplification of algebraic expression without evaluation [closed]

I am using MMA do do some algebra and I need to do some simplification. For example, I have the following expression $$ x^2 \left( \frac{6 \left(2 c_1 x^6+c_2\right)}{x^4} \right)-x \left( 4 c_1 ...
0
votes
1answer
45 views

How to represent one variable in terms of others in a system of equations? [closed]

I have an pretty complex equation set But when I clicked Ctrl+Enter (a.k.a Evaluate Cell), nothing happened. What should I do?
1
vote
0answers
29 views

How define shortcuts to specific OptionInspector points?

I often assign label to cells by OptionInspector (SHIFT + CRTL + O) > CellFrame > etc. It would be great to have the possibility to jump directly to CellFrameLabel or, even better, to edit the label ...
-1
votes
0answers
29 views

How to draw database diagram when connected to SQL Server via Mathematica [closed]

Is there a way to draw database diagram in mathematica?
2
votes
0answers
88 views

What is recommended way to define my function option

In Mathematica 5.x days many packages used the following standard mechanism to read option values ...
2
votes
0answers
35 views

Generation of Space Representation of non-crystallographic Point Groups

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

Manually assigning Axes label position in Plot3D

How can I adjust the position of axes labels with respect to the axes they are bound? Like shifting slightly right or left. I do not what to destroy the graphics' dynamics and render it 2D. ...
4
votes
1answer
86 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 ...
-2
votes
0answers
52 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) = ...
3
votes
1answer
52 views

Havin the problem with solving a nonlinear overdetermined system of equations

I am having a problem to solve a nonlinear overdetermined system of equations. According to one of the previous posts, I tried NMinimize, but it didn’t work. Shall ...
1
vote
1answer
32 views

Issue plotting PDE solution with manipulate

I am trying to plot the solution to the following PDE with the help of mathematica, however, when trying to employ manipulate to animate the behavior, I find that if I try this: ...
1
vote
1answer
55 views

How do I write a function inside a ArgMin

I want to solve this ArgMin[NIntegrate[(Tanh[x] - Erf[x/a])^2, {x, -5, 5}], a] and it does not work, what is the correct way to do this? ...
4
votes
2answers
141 views

Insufficient size of Graphics

The following code returns a framed text box that is longer than the standard width of `Graphics'. ...
3
votes
2answers
55 views

Problem with FindFit: Low quality of estimated parameters

I'm trying to fit a Cole-Davidson formula: ...
-5
votes
1answer
52 views

Finding a seven-digit number with all of its prime factors less than 20? [closed]

How can I find a seven-digit number with all of its prime factors less than 20? I have no clue how to do this.
0
votes
0answers
14 views

Export a .NOFF file without color information

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

Implicit differentiation dx/dt?

I am trying to find $\frac{\partial t}{ \partial y}$ as a function of $x$, $y$ and $\frac{\partial t}{\partial x}$ if both $x$ and $y$ depend on $t$ for the function ...
2
votes
1answer
50 views

Plotting certain time points in a parametric equation? [closed]

I'm using Mathematica 5.0 and I have the following problem. I have the following parametric equation that I plotted successfully. ...
1
vote
2answers
72 views

What's the easiest way to remove overall factors from polynomials?

I have code that outputs polynomials (in #1) such as the ones below (note that the trailing Function character ...
4
votes
0answers
50 views

Numerical instabilities of a convection-(non-)diffusion equation when shrinking from a square to a triangular domain

I am trying to evaluate a parameter-dependent indefinite integral using a PDE-based scheme I described here, and I'm having some trouble when I try and cut down the domain from a square to a triangle. ...
-5
votes
0answers
27 views

what's my air speed if i know these details [closed]

What is the minimum air speed required of an F4 phantom aircraft to accelerate at 10g while pulling the nose up from a 20 degree pitch down attitude?
3
votes
1answer
68 views

How can I numerically pre-compute an indefinite integral with a parameter?

Suppose I have a function $f(t)$, and I want to compute its indefinite integral $$F(t)=\int_0^tf(\tau)\mathrm d\tau.$$ Moreover, suppose that, for any of a number of reasons, I require this integral ...

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