2
votes
1answer
321 views

Laplacian or Grad of an InterpolatingFunction

For obtaining a Schlieren image from an equation for density, I need to calculate the first derivative of density and make a contour plot. The below code snippet calculates the first derivative w.r.t ...
2
votes
1answer
397 views

Inconsistent initial and boundary conditions

I have a 4th order nonlinear PDE with the following BCs and IC: ...
2
votes
1answer
277 views

Borked Find Window in OS X

I've been having this happen to me on a daily basis with the Find & Replace window on OS X: No text can be typed into the red regions, so all find & replace functionality is gone when this ...
2
votes
3answers
598 views

Problem with Union and Intersection

Consider the following: list={{a,b,c},{c,d,e},{d,e,f},...{x_,y_,z_}}; I would like to apply Union on the elements of the list ...
2
votes
2answers
394 views

Cannot evaluate differential in Mathematica

I have a small toy script in Mathematica that I am trying to use to evaluate the pdf of $Y$ where $Y=X^2$, and $X$ is uniformly distributed in $[0,a]$. The script is, ...
2
votes
1answer
173 views

Delete a style type from stylesheet

I have created a new stylesheet but now I'd like to delete a style type, for example "program" from it. How can I do it ?
2
votes
2answers
426 views

How to impose custom style to the edges of a graph

We construct a graph as the following. ...
2
votes
3answers
3k views

Product of elements within a list

Please Consider : list={{5,2,6},{2,8,3}} I need to get the product of all the element within list : As of now I do this : ...
1
vote
4answers
91 views

Replacing more than one element from a Sublist

The following expression allows me to extract the value of x and y: ...
1
vote
1answer
44 views

Numerically Integrating to find a Maximum using NDSolve

I am trying to numerically find an equilibrium (maximum) of a function using its differential. The following is a simplified version. ...
1
vote
1answer
121 views

GUI of a Karnaugh Map

I intend to implement a three-variables Karnaugh map with the following code. There are two points I failed to figure out. How to remove the outer double-line border? How to change the toggling into ...
1
vote
1answer
76 views

Use NDSolve to solve a PDE

I have the following PDE (a master equation, and $P$ is probability density, $0\le x\le1$ and $0\le y\le1$): $$ \partial_t P(x,y,t)=x\partial_xP(x,y,t)+(1-y)\partial_yP(x,y,t)+2P(x,y,t) $$ The ...
1
vote
3answers
66 views

How to limit only two “0 and 1” strings for an xor implement?

I tried to implement some logic gates for a series of "0 & 1" strings, just like and, or, nand, nor and not listed below. How could I limit xor only accept a two strings list as its argument? ...
1
vote
1answer
48 views

plotting 3d points: z-axis is squashed

I am plotting 3D points and it occurs to me that Mathematica doesn't have an easy way to specify my points to be plotted in a uniformly scaled cartesian space. For example I plotted ...
1
vote
1answer
93 views

Factoring terms out of a polynomial

I don't do much algebra in Mathematica and was surprised to discover, while attempting to answer this question, that I had no idea how to factor out an expression from a polynomial. The question was, ...
1
vote
1answer
103 views

Find all roots in the interval of nonlinear equation

I am struggling on how to find all the roots of 1+1/2^x+1/3^x==0 which lie in a given of real and imaginary interval. Solve ...
1
vote
2answers
96 views

Looking for an elegant way to solve a (system of) ODEs/functional equations with undetermined coefficients

I want to solve an ODE using undetermined coefficients/guess-and-verify and am looking for an elegant way to use this technique. I am running into a few ugly warts. Here is a basic implementation for ...
1
vote
2answers
175 views

More efficient implementation for comparing coefficient lists in a Do-loop

I'm wondering how to speed up the following code so it actually computes for $n=2$: ...
1
vote
3answers
176 views

Marking specific points on a 3D curve

Here is the curve below. (written as a position vector) r = {Cos[7 Pi*t], Cos[6.2*Pi*t], 2.5*t} ParametricPlot3D[r, {t, 0, 2}] I want to know how I can mark ...
1
vote
2answers
150 views

On Parameter Estimation using FindDistributionParameters

I am a novice of Mathematica and have recently started my self-study of maximum likelihood estimation (MLE) using Mathematica. I would like to estimate the parameters associated with a distribution ...
1
vote
1answer
82 views

Plot a vector valued function of two variables using color density

I have a vector (3D) valued function of two variables. I want to visualize it as a density plot, using R,G,B color values to display the value at the point (x,y). I've come up with a couple of ...
1
vote
1answer
24 views

$IterationLimit and parallel computing

Short question: How can you set $IterationLimit for parallel computation? I thought just setting $IterationLimit = Infinity ...
1
vote
1answer
81 views

Animating arrows

I have the following Code: ...
1
vote
2answers
82 views

How to set initial guess in NDSolve

I'm trying to solve a BVP using NDSolve and I want to impose the starting initial guess. I googled and looked at the help, but I couldn't find this option. ...
1
vote
1answer
90 views

Solving differential equation - initial condition

I want to solve the differential equation: DSolve[{R''[ρ] + 2 /ρ R'[ρ] + (1 - (l (l + 1))/ρ^2) R[ρ] == 0}, R[ρ], ρ] This works fine and outputs: ...
1
vote
1answer
82 views

Specifying view angle of a 3D plot [duplicate]

I would like to create a stereogram from a 3d plot; I would like to export two images of a 3d plot at a slightly different angle, so that when each picture is presented to a different eye, one gets ...
1
vote
0answers
69 views

What summations can Mathematica do? [closed]

I was very pleased to discover that Mathematica could do this summation and produce a symbolic result. ...
1
vote
0answers
45 views

Combined Elliptic-Parabolic PDE in 1D [closed]

Here is an example of solving a system of parabolic and elliptic PDE: http://reference.wolfram.com/mathematica/tutorial/NDSolveDAE.html (see the subsection "Combined Elliptic-Parabolic PDE in 1D"). ...
1
vote
0answers
73 views

DSolve does not solve my system of PDEs

I am a long time Maple user who had just recently got hands on Mathematica. I have a "simple" system of PDEs, one can be solved easily. But I cant seem to get it work in Mathematica. I am nos sure ...
1
vote
4answers
116 views

How to count number of {True,True} outputs?

Do[Print[{x + y + z == 3, x + y > z}], {x, 1, 2, 1}, {y, 1, 2, 1}, {z, 1, 2, 1}] If I run this syntax I get a series of Outputs, I am trying to Count only the ...
1
vote
1answer
127 views

To solve Cylinderical PDE

I want to solve this PDE. I have tried to solve it with NDSolve but found error 'Boundary values may only be specified for one independent variable. Initial ...
1
vote
1answer
57 views

Turning Off Error messages locally

I'm trying to turn Off an error in an expression. ...
1
vote
2answers
94 views

How to sort the adjecency matrix of bipartite graph so to have two off-diagonal blocks

In a bipartite graphs there are two class of nodes, say A and B. Each node of class A may interact only with nodes of the class B, and viceversa. The corresponding adjecency matrix is thus composed by ...
1
vote
1answer
84 views

How to specify the centre or PlotRange of a Graphics3D?

When I create a Graphics3D, I often want to place an object right at the centre of the box. Initially I thought that the centre was specified by ...
1
vote
1answer
75 views

Operator operation

There are two basic operators r={x,y,z} and p=-I*h*{D[#,x] , D[#,y], D[#,z]} &. The angular momentum operator is defined as ...
1
vote
2answers
336 views

How to use ContourPlot3D for Piecewise 3D function

How would I plot in 3D: $\begin{cases} (4 - z^2) = x^2 + y^2, 2 \le z \le 4 \\ x^2 + y^2 = 4, -2 \le z \le 2 \end{cases}$. I tried http://reference.wolfram.com/mathematica/ref/Piecewise.html ...
1
vote
1answer
135 views

How to reverse the direction of the y axes on Graphics

Question related to this one, except I need the same for the Graphics. Lets say I have the following drawings: ...
1
vote
2answers
108 views

`Slot` (#) interfering with evaluation

In the following I am using one function makeFunc to assemble two functions a[t] and b[t] to ...
1
vote
2answers
275 views

Why doesn't Abs simplify further?

Why does this: Simplify[Abs[x + I], Element[x, Reals]] give me Abs[x + i] Is there a way to force Mathematica to give me ...
1
vote
1answer
95 views

Confidence Regions for NonLinearFit with “complicated” integral model

I have a set of data $y_i (z_i)$ with errors $\Delta y_i$, that can be found here Here Thus first, I call the data ...
1
vote
1answer
139 views

NonLinearFit with “complicated” integral model

I have a set of data $y_i (z_i)$ with errors $\Delta y_i$ ...
1
vote
1answer
69 views

FindFit::nrlnum What am I doing wrong?

I have a model called qobs: ...
1
vote
1answer
60 views

Reading Options from DateListPlots with legends

Normally I can recover the options used on a DateListPlot easily with Options[]. However if one of the options said a Legend should be attached, it appears all the options are then unreadable. For ...
1
vote
1answer
103 views

Having trouble assigning the result of a Solve to a function

Can anyone see what is wrong with my syntax? It looks like I have successfully assigned the result of Solve to a function. I want Mathematica to return me an numeric value of the function ...
1
vote
1answer
166 views

Plotting Zeros of a Complex Variable

I'm trying to plot the zeros within a certain distance from the origin using Mathematica of a given function (in my case, partial sums of the Zeta Function). I've tried plugging in simple functions, ...
1
vote
1answer
122 views

Can ParametricNDsolve be used for coupled PDEs with 5 parameters?

I have a system of coupled PDEs with five parameters that I only know ranges for rather than explicit values, and I was wondering if I could define a parametric equation with ParametricNDSolve and ...
1
vote
1answer
88 views

Extracting Imported Information

What I want to do is to compare the relationship between the consumption of say beer and wine using scatter plots where each point designates the particular country (preferably named). I have tried to ...
1
vote
2answers
135 views

intersection between function and plane

I try to solve a ODE system of equations and i want to plot the intersection of the 3D solutions with a costant plane. To do this i use the follow code: ...
1
vote
2answers
102 views

Is there a way to “hold” prefix / infix / postfix notation?

Is it possible to preserve a specific style of notation in $Mathematica$ output? foo // bar (* bar[foo] *) Hold[foo // bar] (* bar[foo] *) I'm writing some code ...
1
vote
1answer
77 views

How to assign Subscript[C, i] to a Sum?

What I want to show is: Plot3D[ Sum[1000*Subscript[C, i]^2/(1000*Subscript[C, i] - 600)^r, {i, 1, k}], {k, 1, 30}, {r, 0.1, 1.5}] And, I want the list of ...

15 30 50 per page