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3
votes
3answers
122 views

Creating a matrix under conditions

I would like to create a matrix whose elements satisfy the following conditions ( Mathematica 9 ) ...
0
votes
1answer
29 views

How to input an adjacency list?

I am a beginner user of Mathematica, and I have an assignment to construct a graph given n (number of vertices) and an adjacency list. My idea was to make a For cycle that repeats n times, and for ...
2
votes
2answers
80 views

Dynamic arrays and lists with compile (Append, Linked lists etc.)

I have a code that I need to compile. The code contains a loop in which I need to gather data into a list. The question is how to best gather data so that the code works inside Compile. The following ...
1
vote
1answer
53 views

How to extract a contiguous s_1 x s_2 x … x s_d subarray from an n_1 x n_2 x … x n_d array, where the dimension d is a variable

Given a multidimensional array, such as the 3-dimensional 2 x 2 x 3 array { {{a,b,c},{d,e,f}}, {{g,h,i},{j,k,l}} } How can I extract an arbitrary 3-dimensional ...
1
vote
2answers
150 views

Manipulating elements of a matrix, to loop or not ?

I have a grid of values generated from a MATLAB evaluation. Most of these elements are 0, some 0.5 and the remainder 1. I'd like to write a mathematica script which reads in the CSV and then, in every ...
0
votes
1answer
53 views

Creating a symbolic function dynamically given an array of data

I have a function that is based on the numeric values of a random sample that I would like to maximize: ...
5
votes
4answers
498 views

Elegant mehod of generating this matrix?

Good evening, I need to determine an elegant (as possible) method of computing an nxn matrix below (the matrix shown is just a 16x16 example). I've been toying with For loops, Tables, Bands, ...
0
votes
1answer
44 views

Export array data into a file

I tried to solve some equation for different values of parameter t and put results into array. Then I wanted to write this data into a txt-file. So i did it with ...
2
votes
2answers
81 views

How do I get all the roots within a certain range for an equation? [duplicate]

I wish to find ALL the roots of the following equation $ x \tan(ax) - c = 0$ within a range, where a and c are constants I control. I've been using ...
4
votes
5answers
290 views

Check whether array has only constant entries?

I have an array arr with n entries. Now I want to check whether ...
0
votes
1answer
53 views

How to split (large) arrays like this?

I want to split this table (list/array) ...
0
votes
2answers
47 views

Getting RandomChoice to work in Manipulate function

I'm a beginner mathematica programmer and I am tryin to create my first demonstration. This code should represent what happens if one changes the size of the reading frame, calculating the nucleotide ...
2
votes
2answers
60 views

How to share numbered variables between kernels

Supose I have two variables v[1] and v[2]. I used: SetSharedVariable[{v[1], v[2]}] Then, ...
1
vote
1answer
66 views

Shifting Columns in an Array Efficiently

I am trying to find a more efficient way to shift the columns of the partitions of an array according to a defined slope and fill in the shifted regions with zeros I have done it below but, I know it ...
0
votes
1answer
49 views

How to assign the array data to variables?

A very basic question but puzzled me for long time on how to assign array to variables. For instance, we have array {{t1,x1},{t2,x2}...{tn,xn}} how to assign the first element to variable t and ...
2
votes
1answer
84 views

ListContourPlot

I am having some issue with ListContourPlot. When I define the following Array: ...
0
votes
1answer
79 views

Array element problem in optimization

I have the following piece of code in Mathematica: ...
0
votes
1answer
108 views

Block matrix and calculate it's inverse

How to define the following block matrix $$ A=\begin{bmatrix} H-G_1 & -G_1 & \ldots & -G_1 \\ -G_2 & H-G_2 & \ldots & -G_2 \\ \vdots & \ldots & \vdots & \vdots ...
0
votes
1answer
27 views

Defining an array using this specific rule [closed]

To a pair of natural numbers $(m,n)$ I would like to associate the $6(m-n+1)\times 2$ array whose rows consist in all pairs $\{x,y\}$ of natural numbers where $m\leq x \leq n$ and $y\in[\lceil x/5 ...
0
votes
1answer
60 views

Entering block matrices, general case doesn't work

I want to enter several matrices at different positions in blocks. There is already a very similar answer here: http://mathematica.stackexchange.com/a/3562/6138 I thought that simply generalizing ...
3
votes
2answers
169 views

Pairwise similarity comparison

I have a 444-member array of arrays called final, with each subarray containing 12 integer members. How can I do a pairwise comparison of the contents of the ...
1
vote
1answer
94 views

Graphic timeline from array

I found this question where someone put some code to graphic a timeline based on a certain number of events. In that code in particular, the events are hard coded one by one, I want to modify it, so ...
2
votes
2answers
55 views

editing entries of a sparse array + sparse Smith normal form

Why does the following code ...
2
votes
2answers
59 views

How to delete certain unwanted elements from an array

Suppose I have an array like so array1 = {{Null,2,3,4,5}, {a,b,c,Null,e}, {w,x,Null,y,z}} Is there some way to selectively remove any element I ...
0
votes
0answers
30 views

Importing large arrays and releasing memory

I am trying to import huge 3 dimensional arrays (in my case approximately 2GB) which I calculated before and saved in .MX format. Then I want to work with a smaller ...
3
votes
1answer
83 views

Fast list interpolation over common x,y for multiple variables

I have a (long, >50K elements) unstructured list with a header similar to; AList[[1]] = {x,y,z,var1,var2,var3,var4,...,varN} I want to interpolate z, var1, var2, ...
0
votes
0answers
59 views

Is there a command like meshgrid in Mathematica? [duplicate]

Just like the title, I need to do a meshgrid in Mathematica, is there any command like that?
10
votes
3answers
283 views

Sorting Lists of lists of arbitrary length

I'm trying to sort a list of lists. The sublists are defined in length, but the length of the list containing it varies. A simplified set might be: ...
6
votes
3answers
256 views

List Manipulation on Array with subscript elements

I am trying to write a function which operates on an array with subscripted elements. As an example i have the array a={$1_3$,$2_2$,$4_1$}, which means i have 3 amounts of value 1, 2 amounts of value ...
3
votes
4answers
157 views

Plotting recursive from a for loop

our assignment is that we have make a plot for the possition of 1's From the recursive function if a[n-1] is even then ...
-2
votes
1answer
193 views

How do I store values in a for loop into an array and then plot that array? [duplicate]

What my title said and I want to plot the values of the array. still new to mathematica and programming so its hard to formulate my question just right
7
votes
2answers
96 views

Recursive function with array of variables

I am trying to create a recursive function which works with an increasing array of variables. Since the formula is quite complex, i will try to simplify my example to the core of my problem. The ...
3
votes
2answers
327 views

How to create a 'shortest-path link matrix'?

I am currently struggling with a problem in Mathematica. I have a randomly generated weighted Barabasi-Albert graph and a corresponding demand matrix of the same size. I'm generating the graph with ...
2
votes
0answers
79 views

An efficient way to merge a pair of 4d arrays of non regular length lists

Question I have two 4 dimensional non regular length lists of complex values. I have working code however it seems quite slow and I am not sure how I could improve this. Mathematically I am trying ...
1
vote
2answers
64 views

Generating an Array of Vectors

I'm working a lot with nested lists of $(x,y)$ coordinates (of a FEM-like mesh, but that's not important), like so: ...
6
votes
8answers
340 views

Merging lists and adding common elements [duplicate]

I have two 2D arrays where some of the x-values are identical, L={{1,1},{2,2},{3,3}}; J={{0,1},{2,2},{4,4}}; I want to add these lists in the following way ...
1
vote
4answers
109 views

Converting format of list

I have a 2D array, data = {{0,1}, {1,2}, {2,3}}; I would like to convert it such that I get the x- and y-values separately, specifically ...
1
vote
3answers
53 views

Collect the lists

I have a list of lists from which I pick out the positions of the number 1 and then print out these positions for each list. I am having some trouble collecting what I am printing into a list / matrix ...
1
vote
1answer
166 views

Plot Legends and Frame Ticks in Array Plots

Why do the frame ticks go away when PlotLegends->Automatic is inserted in an Array Plot? For instance, the following code produces an Array Plot with Frame Ticks. ...
0
votes
4answers
90 views

Drop row if sum of part of row is equal to zero

My problem is the following: Suppose I have a matrix A which looks the following: ...
0
votes
2answers
73 views

Can `Array` work as `Loop`? [closed]

I got Mathematica code from my friend: ...
0
votes
0answers
24 views

How can I give input to an ArrayPlot [duplicate]

I would like to create a dynamic ArrayPlot so that the squares, when clicked, provide input. Can I use ArrayPlot for this? Or is there something else I should have to use.
0
votes
2answers
78 views

Import array indices from Excel

In an Excel file, I have some numbers which I will use as the indices of arrays. I want to read those numbers and assign them as the array indices in Mathematica. For instance, in Excel I have and ...
0
votes
1answer
105 views

Import a data stored in EXCEL and change it to a Table [closed]

I have an EXCEL file in which large amount of numbers is stored in a column in the first sheet, like data in the column A of the sheet1 of excel file. When I apply the Import function; the data is ...
10
votes
1answer
250 views

Using Mathematica to make a graphics array of circles

I need to make .svg file that contains an array of black circles that all have radii of 5 units ad are evenly spaced apart from each other 32 units. The difficulty in creating this design is the ...
0
votes
1answer
121 views

Finding the first five eigenvectors and values for a 500×500 matrix

I'm trying to find the first five eigenvalues and vectors of a matrix that has the following proporties: ...
4
votes
4answers
158 views

Better way to select all array indexes matching predicate?

I'd like to select (offset) indexes of a number of array points, that match a selection criteria. I can do this by creating a Table of all the coordinates, and then selecting all the values: ...
2
votes
4answers
176 views

Replacing High Densities of 1.s in Very Large Binary Arrays

I am working with very large binary arrays on the order of {100,100000}. It may look something like this. ...
3
votes
2answers
121 views

Replacing Patterns In a List of Varying Length

I am working with an array of data that may look something like this. ...
0
votes
0answers
185 views

Solve function doesn't work

I have the following system of equations that I need to solve: ...