# All Questions

140 views

### Import and export without changing number format

I have a complex file that is the output of a program. The file contains multiple columns with data in different number formats. For example: ...
276 views

### What is the “proper” way of multiplying a list of vectors by a matrix? Why Map does not work? [closed]

I am an absolute newbie with Mathematica, so please forgive me if this is stupid, but for the life of me I can't solve this. Suppose I have a list of vectors $b_{1...n}$ and a square matrix $A$ and I ...
217 views

### How to make a world map with a coloured ocean and transparent land surface?

I'd like to make a world map with a blue coloured ocean and transparent land surface (to be used later as an overlay). With: ...
70 views

### How do I apply a conditional append rule to plot randomly chosen points?

I'm working on an attempt at forming a sort of "Mandelbrot" set using Newton's method and randomly chosen points. Effectively I need to define a loop for Newton's method to determine whether my points ...
335 views

### Matching pair of numbers {a,-a}, where a is numeric

Imagine you have a list of pairs of numbers, such as {{2,-2}, {1,5}, {1,-3},{-3,3}} The task is to reduce the given list to a list of pairs of type ...
114 views

### Error when combining Except, “*” and an additional character

Bug introduced in 5 or earlier and persists through 10.4.1 Anyone knows why ...
194 views

NDSolve::bcedge: Boundary condition c[t,5]==Cout is not specified on a single edge of the boundary of the computational domain. >> I'd like to plot $\frac{\partial}{\partial t}c=\frac{d}{r^2}\frac{\... 2answers 280 views ### random discrete data 3D plot I get the random discrete data as follows ... 2answers 83 views ### Writing a function with variable arguments [duplicate] I want to write a function which takes multiple arguments varying from 1 to n, where each argument is a triplet. sublistProduct[{$a_1,b_1,c_1$},{$a_2,b_2,c_2$},...] = {$\Pi_{i=1}^{i=n}a_i ,\Pi_{i=1}...
128 views

I have a list of about 50 conference attendees with 3 columns (First name, Last name, University). I would like to use Mathematica to generate the conference badge for each people. The badge dimension ...
45 views

### Using list of values as argument in a function [duplicate]

could you please help me with a task. I would like to define a function with a list of values as an argument. There is a working code with a values {1,1,1}: ...
66 views

### Simplify with assumption of unknown function [duplicate]

I have an unknown multivariate function entry[x,y,z], which is positive. Then how to get FALSE and entry[1,2,3] in the following evaluations? ...
724 views

### A too complicated lookup

I have the following keys: nm = {"bay", "ica", "rat", "tat", "dax", "dow", "sp5", "nas", "mean", "total"}; which I want to use to find a corresponding entry in ...
187 views

111 views

### Automatic AutoIndent while editing a Package (.wl)

The author of this question is interested to personally handle the code indentation and have the package editor, built-in in Mathematica 2012, preserve the manually chosen indentation level from line ...
269 views

### Using ArcLength in Mathematica 10 using absolute values

With Mathematica 10, I can nicely plot: y = x^2 - 4 Abs[x] - x But I have not been able to use ArcLength to get the length of ...
69 views

### Variable not assigned to correct Context [duplicate]

I am trying to understand Mathematica's Context, but I do not understand why the short name of the variable defined in the temp` context (x) returns the Global definition. I am following the section ...
169 views

### Make a colored ListPlot

Basically I have a set of 3D points, such as {3,4,3} or {4,1,4}. Instead of plotting the points in a 3D space, I want to plot the x,y coordinates of the points on the 2D plane and use the z coordinate ...
52 views

### Computing integral involving derivatives

I want to evaluate an expression $\int_C g(\nabla f)ds$. This is an integration along a curve $C$ in a plane given as a function of some parameter $s$: ...
205 views

### Nested If statement with unevaluated arguments

I have a list of boolean functions {f1, f2, f3, ...} that take a value and return True or ...
94 views

### Improving semantic interpretation of dates

SemanticInterpretation and Interpreter are promising but imperfect, eg extracting dates and calendar expressions from semi-...
314 views

### Minimalistic code challenge on Apollonian gaskets

I've been recently fascinated by the beauty, symmetry and mathematical richness of the Apollonian gaskets. So I felt myself challenged to see if it was possible to generate one in Mathematica with ...
576 views

### Step-by-step instruction to Install C Compiler

I remember using C compiler on my previous computers, and I never had any problems installing them. At this time, however, I failed to work through the instructions provided in Mathematica ...
63 views

### Transforming functions

I am not familiar with Mathematica but have the following question: I am trying to write Mathematica code that transforms $x^a+y^a$ to $(x+y)^a$ for any $x$ and $y$ and integer $a$. I also need to ...
96 views

### How to show all terms of a (very) large expression which was cut by skeleton << >>?

I obtained a very large expression but I noticed that Mathematica omitted some terms and wrote <<1>> or <<8>> instead. I would like to see all terms in order to write rules that simplify ...
115 views

### cross point of intersecting lines [duplicate]

What is the easiest way to find the crossing point of two intersecting lines passing lets say through points line1 = {p1,p2}, line2 = {p3,p4}?
90 views

### DSolve response with DSolve

I'm trying this code ...
92 views

### Looping within linear programming

I am trying to do some network programming around optimization. Here is a reduced sample: ...
70 views

### How to stop a Dynamic[] in one notebook from hurting performance in another?

I have two notebooks open, one has a dynamic expression running (a simple clock) ...
203 views

This code: ...
93 views

### imaginary part in optimization problems

I have some trouble with an optimization problem. The constraints are always real, but in the first place there are also complex parts in the expression (which all sum up to 0). The problem now is ...
296 views

### mathematica use too much memory to Import large dat file

Err... When I try to Import a .dat file by dat = Import["D:\\TIEGCM\\solar_input\\omni_m_all_years.dat", "Table"]; or ...
445 views

### How to simplify and shorten pattern code?

I this code to sorting only those tuples that are have total sum of 15 without repetition.: ...