# All Questions

201 views

### Faster trimming of leading/trailing zeroes in rectangular array

Given a (large) rectangular array, e.g. (small for example case): ...
54 views

### How to make work Plus function? [duplicate]

I have a little problem. I have k = 1.56343*10^9; r = 9.10492*10^18. And I should receive a (2*r*r-k*k)/2*r*r, it equals to ...
212 views

### Use a Module to return multiple plots

A program I'm running requires me to generate multiple plots over the same domain, so I thought it would be fairly simple to use a module and bury all of the plot commands within that that way I only ...
242 views

### Nearest neighbor distribution

I need to construct nearest neighbor distribution for a given finite set of real numbers. I have no clue how this can be realized. Any suggestion would be very much appreciated.
63 views

### MousePosition and While loop Control, maybe Dynamic in While statement?

I would like to write a simple code that samples mouse position as frequently as the system can handle (with minimum dt) starting when the mouse position leaves a region and ending when the mouse ...
55 views

### Add Numbers to Notebook Cells

Let's save I have a notebook full of text cells. How might I add numbering to the text cells?
52 views

### Collecting specific Lists of data in coordinate form

Note: This might be trivial for many of the users but i am new to mathematica so i don't know!!! Question: Suppose i have three list of data as follows: ...
135 views

### Error with using NDSolve [duplicate]

I am currently trying to numerically solve a system of differential equations. Here is my code: ...
121 views

### How can I calculate the maximum number of grid layout possibilities?

I am doing some modelling where I am trying to randomly layout some points on a grid. What I know: How big the grid is The number of objects that have to be laid out on the grid, at a point The ...
57 views

### What is the correct idiom for mapping a 0 value in a modulo n expression back to n?

What is the correct idiom for mapping the $0$ value in a modulo $n$ expression back to $n$. For example if I want to be sure that any integer value maps back to the index for a character in the ...
90 views

### Can I redefine the ++ increment operator to make it behave like Haskell

In Haskell, joining two lists l1 and l2 is simply done with l1 ++ l2 In Mathematica ...
435 views

### Calculating average distance between maxima

I'm having trouble figuring out a way to analyze some simple data. When graphed, the data I have make a somewhat sinusoidal curve. What I want to do is to find the x-values of the maximum peaks of the ...
168 views

### Using Wolfram Library Reference in Excel VBA

Long time ago I did this question to MathGroup, but without success. In Excel VBA, in Tool/References, there is a option called "Wolfram Mathematica Control 8.0 Type Library" I belive that ...
71 views

### How to combine 2d and 3d plots with this code [duplicate]

I found a picture for example in google and I want to do with my code like that: And here is my code: ...
64 views

### Integrating the second derivative of a 3D curve

I have a 3D curve K2[s_] := c1[s] + 0.4*(j[s]*Sin[500*Pi*s/97.8] - v[s]*Cos [500*Pi*s/97.8]) where j and v are frame vectors. I want to find the integral of ...
246 views

### How to access an already opened Excel file in Mathematica?

This post 4594 shows how to open a existent Excel file with Mathematica. And this 6686886 shows how to do what I need, but in C#. This 12282310 is another related one. How can I connect to a ...
104 views

### Is there a way to change the indentation behavior of the postfix operator //?

For example, using newlines after // results in some really weird indentation: Ideally, I'd love to be able to do something like this: ...
168 views

### Finding a formula for a 3D shape and colouring it

I created a wall with line command ...
473 views

### FindShortestTour to solve Traveling Salesman Problem

I'm trying to write my own code to find the shortest route but I'm lost on how or where to start. Does anyone have any idea how the FindShortestTour function works? What type of algorithm or structure ...
120 views

### Dataset Query using Composition fails but RightComposition works - why?

V10.1 on Win764 Enterprise. In this (CORRECTED) example the two Queries may be compounded into one using RightComposition sucessfully... ...
206 views

### why MeanFilter is nearly 100 times slower than MovingAverage for 1D array?

I used to average over my data with MeanFilter before I learn about MovingAverage and thought that these two functions are similar except that MeanFilter is more powerful for its ability to deal with ...
60 views

### Input text next to plot axes

Please see the following image showing my plot. I would like to indicate $\omega$ is maximized at $\bar{\omega}$. But as you can see, it is cut and does not appear correctly. Do you know how to fix ...
64 views

### Boundary condition not correctly imposed for NDSolve

I notice that when plotting the below NDSolveValue ...
1k views

### Finding the period of an array of integers

A simple array of integers is given. The problem is to detect if a pattern is repeatedly occurring in the array, and find the length of that pattern. For example, for ...
149 views

### Failing to solve a simple PDE with NDSolve

I'm trying to solve the following PDE. Actually this is a major simplification of the original with all x,z dependent coefficients being fixed. For some reason Mathematica (10.0) cannot solve even ...
174 views

### compute the gradient in high dimension

The following code is used to compute the gradient of a given 2D data. ...
149 views

### Collect distributed sums

I have another task that somehow should be trivial. Suppose I have the following expression $$\sum_{i=1}^n \frac{2}{9} x_i + 2 \sum_{i=1}^n \frac{1}{9} x_i,$$ or in Mathematica-FullForm ...
68 views

### Speeding up EPS exporting ?

I'm using Mathematica 10 to render some figures, and I'm noticing some strange behaviour with EPS figures. I'm making figures like the one below in EPS format. And to do so, I use some code like ...
250 views

### Plot with tick labels but without ticks

In scientific literature, plots often have a design like what I've been trying to make (see below). These images have the following characteristics: 1) Frames on the left and on the right 2) An x-axis ...
72 views

### What is the meaning of the lists of numbers in the FullForm of a compiled function?

For example, f = Compile[{{x, _Real}}, x]; FullForm[f] has this output: ...
29 views

### Roots of two Functions containing integrals, with two parameters [duplicate]

I want to find the values of l1 and l2 from the following two equations: ...
173 views

### Solving coupled differential equations with an eigenvalue

I have 2 coupled differential equations with an eigenvalue Ei and want to solve them ...
72 views

### Perform operation on part of a table / create a reference

There is a function f that I would like to operate on a rectangular part of a table t. The part is specified by function ...
145 views

### Optional arguments with lists as function parameter

I'm developing a function f which should support optional arguments {x_, y_} in list form. A simple example looks like this: ...
104 views

### How to convert absolute time to local time?

I tried this code: ...
92 views

### Can we say that “all functions in Mathematica are some kind of pattern-matching-and-replacement procedures”? [duplicate]

Currently I am studying Mathematica programming, and when I study pattern matching and replacement, I find it is quite similar to functions. So can we say "all functions in Mathematica are some kind ...
64 views

### Solve on parametric equation produces inequal results

I have a parametric (parameter t) equation in two dimensions (vectors). s = Solve[pt[t] == qt[t], {a, b}] Both pt and qt are parametric lines using a and b as ...
93 views

### Problem in matrix multiplication

I created a random directed acyclic graph using Mathematica. I need to compute a specific function from its adjacency matrix. ...
95 views

### Error Exporting STL --insufficient elements to export

I am trying to export the following code as an STL file: ...
170 views

### Eigen energies of 2D time independent Schrödinger equation

Firstly, I am aware that a similar question of this type was asked, but it was not helpful as it was only one dimensional (so please don't mark my question as a duplicate) The trouble I am having is ...
438 views

### Geocentric, Earth-fixed, coordinates of Sun, Moon (and others objects eventually)

I know I can get "HelioCoordinates" of the Earth and the Moon with ...
51 views

### DisplayFormula badly rendered if style is set before writing

If I have to write a display formula, I go to the cell after the text cell I'm currently into, select the DisplayFormula from the Style menu and then write. The ...
66 views

### Can association be used to find the maximum key less than a specific number?

Suppose we have an association assoc. assoc = <| 1 -> 1, 3 -> 2, 5 -> 3, 7 -> 4, 20 -> 5|>; Instead of ...
74 views

### Unnecessary free space under the figure

Here is the data ...
54 views

### ListLogLinearPlot with Legends

I need to plot this data in Log scale for both axes, and also need to add a legend. But since they are joined dots, the legend that appears is just a dot instead the plotstyle I choose. ...
114 views

### Series with a specified number of terms

I'm doing calculations with Series where I don't know the power of the leading order term. I would like to keep a specified number of terms, but since I don't know the leading order this is proving ...
147 views

### Plotting points on the horizontal line

I have list such as list = {1, 5, 2, 6, 3,...} and I need to plot the numbers from the list on a horizontal line such that there will be on a place on horizontal ...
258 views

### NonlinearModelFit: fit a vector-valued function to a data vector

I have a vector of data points: data = 10 Sin[#/10] + RandomVariate@NormalDistribution[] & /@ Range[200]; And I have model that provides the complete ...
Does anyone have a good technique for creating a random $2\times 2$ matrix that has one eigenvalue of multiplicity two, but only a single eigenvector? And more generally, has anyone written a ...