# All Questions

13,457 questions
612 views

### Extract variable and coefficient from equation elegantly

I have quadratic equation like $eq = x2-7*x5^2$ and vector $xx=\{x0,x1,x2,x3,x4,x5,x6,x7,...\}$. I need to do some nice calculations which will give me coefficient $k=7$, $y=x2$ and $x=x5$, so that ...
116 views

### Implicit function: derivative of piecewise function that has a FindRoot in one of the pieces

I have a piecewise function that has as one piece the result of a numerical approximation, like in the example below: ...
179 views

### Find *all* numerical solutions to cosine based equality

To help with https://astronomy.stackexchange.com/questions/11456/ I'm trying to find all numerical solutions to: 5.20427*Sin[0.529699*t] == Sin[2*Pi*t] Since the period of the first function is ...
842 views

### Combine Plots into a single non-rasterized Graphic with no spacing [duplicate]

Suppose that I have two plots, pl1 and pl2: ...
78 views

### How can I show constraints on parameters in 3D plot? [closed]

How can I exclude a region in a 3D plot? I have done it for a Density plot, but for the 3D case, it seems difficult to exclude a region (with a certain relation between two main parameters). In fact,...
170 views

### Initiating another Kernel?

How can I start a separate kernel to do other work, while I have Mathematica working on a problem that requires lots of computation time? I have a program that must be run for many hours, preventing ...
137 views

### Resulting list of ComponentMeasurements

I detect a single bright object in an image with the following code; ...
161 views

### Inverse of a multivalued function

I try to get the inverse of a simple function like x^2,x≥0. Still, when I use InverseFunction Mathematica gives me back -(y^0.5) ...
2k views

### Plotting a piecewise function [closed]

I'm having trouble plotting the piecewise function below. The only way I can replicate this function is using ...
75 views

### Large Community Clustered Network Formatting

I created this visual of a network using: CommunityGraphPlot[adjmatrix, VertexLabels -> "Name"] It looks like this: Is there a good way to expand the nodes ...
256 views

### Solving the 3D Poisson equation on the surface of a cube using a relaxation method

The code below is from another question asked by someone else about solving the 3D Laplace equation for truncated octahedron in a cube matrix, How to solve Laplace equation in 3D?. I wanna know, how ...
205 views

### Drawing a large set of Graphics3D cylinders provided a set of cylinder specifications in a list

I'd like to draw a large number of 3D cylinders using Graphics3D. My list specifying the cylinders has elements that look like the following: ...
525 views

MWE ...
357 views

### String quotes elimination

I'm trying to import a .csv file that contains some points which are geo-positions, but the import gives me the points wrapped in quotes. Is there any method to get them as pairs of real numbers? I'm ...
543 views

### How can a package use a variable of a notebook?

I have defined a function g in a package. It is: g[x_]:=x/.t->3 Now I work in notebook with the command: ...
83 views

### Finding surface fit on 3D graph that have different data length

I have a question to find the surface plot on the list of data with different data length. Each of the sample a different length, how can I combine all these data and find the best fit surface for ...
107 views

182 views

### Compiling function solving for the smallest eigenvalue of a matrix

I am trying to speed up my code, which many times finds a lowest eigenvalue of a Hermitian (symmetric, real) matrix. Using a small 2x2 matrix as an example, this works: ...