Questions on the manipulation of List objects in Mathematica, and the functions used for these manipulations.

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3
votes
4answers
162 views

Rearranging a set of numbers

I have this set of numbers, that is a range of prices (ie 6-10) and a quantity of products (5) ...
3
votes
2answers
143 views

Creating a list from other lists and varying the number of elements that get added

Suppose I have listA = {M, F} and ListB = {a,b,c} I want to make a new ...
3
votes
3answers
231 views

Function[] argument nesting for operations like Select[]

The following code selects a special element from a list thelist = {"this", "notthis"}; Select[thelist, (# == "this") &] What I want is a function which ...
3
votes
2answers
90 views

Inverse action of Thread

I cannot find the original post now, but I'm quite sure that there's an amazing post teaching us how to do Thread on ragged lists. but my problem is how to inverse ...
3
votes
1answer
92 views

remove unevaluated cells from table

I have created a table Tv where each row is of the form {x, y, Iv[x,y]} where Iv is some complicated numerical integral and <...
3
votes
1answer
74 views

Implementing the Cimmino method [closed]

What am I doing wrong? I am trying to implement the Cimmino method, an iterative method for the solution of linear algebraic systems. The final output should be a vector. Here is a description of the ...
3
votes
1answer
124 views

Plotting a table with many y values

I'm trying to plot a bifurcation map for a Lorenz System. I have a function (called estables in the code that follows) which, for a certain value r, returns the ...
3
votes
4answers
137 views

Find the length of the intersection of two lists including duplicates

I have 2 Lists. The first one includes all the numbers from 1 to 10. listA={1,2,3,4,5,6,7,8,9,10} The second includes ...
3
votes
1answer
70 views

Calling results of applying f to expr inside NestList

Being new to Mathematica, I try to follow the suggestions of using NestList, Map, Table ...
3
votes
2answers
70 views

Calculate Cumulative Mean and Standard Deviation of a list without FOR loops [duplicate]

I have a simple list mylist={x_1,x_2,...,x_N};. Now I want to map a function over this list, e.g. the Mean and StandardDeviation functions, so that it will give me ...
3
votes
2answers
101 views

How to gather a list whitout no repeat element to nearest a certain number

Background: The question derive from this question.But some criteria is omited by me.So I try to post a new question for this.If my expression is dimness and you have got it,just tell me or edit my ...
3
votes
2answers
39 views

Setting initial conditions of a domain grid?

So I'm writing some code to try and produce a cellular automaton which will model an oscillatory chemical reaction, but I'm trying to set up the initial conditions of the grid so that I can vary them ...
3
votes
1answer
90 views

How do I convert Subscript[{4, 5, 1}, 7] to the integer 4*1 + 5*7 + 1*7^2 = 88?

I am working with the finite fields package in Mathematica 9. If I input: GF[7, {-2, 0, 0, 1}][{3, 4, 1}]^2 Mathematica gives me $\{4,5,1\}_7$. I want to ...
3
votes
1answer
85 views

Solving a list of equation which takes so much time

I try to solve a list of equation in a following way but it Mathematica solves equations after 30-40 minutes or don't solve them at all. The functions that I use are ; ...
3
votes
2answers
202 views

Tracing 2d coordinates by using Nearest function

In 5 digital images I have determined the 2d coordinates of detected objects. The resulting coordinate list can be downloaded from here: http://pastebin.com/7bE0CEJ5 ...
3
votes
3answers
118 views

How can I make custom accumulated sequences like the following?

First of all, I don't really know how to formulate the question, so if you understand my question and know a better way to phrase it, please revise. I have the following Matrixes: ...
3
votes
2answers
63 views

How do you add one chart to the right of another? [closed]

I have two charts, and I would like to insert the data from one at the end of the other. However, the one chart has multiple ListLinePlots, and when I use Show to try and place the two together, the ...
3
votes
1answer
196 views

Animating N points

So I'm trying to create an animation of N interacting particles in two dimensions confined in a box. Generating the data is fine and it's being stored in a text file with two columns for each particle;...
3
votes
1answer
60 views

How does levelspec work inside Position?

Please, can you explain the following feature of levelspec inside Position ? This code test=Range[5]; Position[test,x_/;x>2] as expected, gives ...
3
votes
1answer
130 views

Programming a MaxMin Linear Optimization

I want to program a function for a two-player game. Basically it's like this: . Each player has an array of options, and the result of the game is based on both players choices. So heres my most ...
3
votes
1answer
44 views

Simplifying nested KroneckerProducts

Any suggestion how to bring a nested KroneckerProduct form into just one? I mean some how converting ...
3
votes
2answers
83 views

(Again) eliminate curly brackets from PopupMenu?

How can I display the items in a PopupMenu , which is fed by a list, without the curly brackets? The sample code is: ...
3
votes
1answer
626 views

Use a part specification as the argument to a compiled function

I have some code that needs to generate a large matrix based on some complicated combinations of smaller matrix elements. I find that if I write a function for the element of the larger matrix, and ...
3
votes
1answer
99 views

Count two or more equal consecutive elements in a list and create histogram

I have a list generated by: list = RandomInteger[{1}, 100] it contains only 0's and 1's ...
3
votes
2answers
96 views

Retaining relative sizes of local maxima using MaxDetect[List]

I would like to be able to find the position of the two greatest local maxima in a list. For the example: list={1,2,3,4,2,1,2,6,5,4,3,2,} I would like to return <...
3
votes
3answers
103 views

Combining $n$ lists [closed]

From this question, I know how to combine two lists. In fact, if $X_1,X_2, X_3$ are lists with the same length, then the command Transpose[X_1,X_2,X_3] will work in ...
3
votes
2answers
102 views

Average list of list of parameter values [duplicate]

I have a list of lists of fitted parameter values, e.g. list={{a->1,b->10},{a->2,b->20},{a->3,b->30}} (the actual parameter names can vary, as ...
3
votes
2answers
166 views

Replace missing data

I have vectors of equal lengths where I want to replace the zeroes (missing data) with their preceding values. So far I have written: ...
3
votes
1answer
211 views

Functional programming approach to avoid traditional loops

I'm currently learning from the wonderful post: Where can I find examples of good Mathematica programming practice? And i'm correcting my habits using Nest/Map/Thread instead of loops. The problem ...
3
votes
1answer
126 views

Given a list made up of subsets of an alphabet, how can I use associations to create a Boolean dictionary of the given list

I have a list of 30,000 elements, each of the element is a list in itself {{a, b}, {p, q, r}, {a, p}, ..., {z, x}}. Second one contains unique elements ...
3
votes
1answer
166 views

Calculate efficiently an expensive hermitian matrix

I want to compute a matrix $M_{pq}$, for which the calculation of each coefficients $M_{pq} = f(p,q)$ is an expensive function. I know that my matrix is hermitian, so that $M_{qp} = M_{pq}^{*}$. As a ...
3
votes
4answers
242 views

Trouble with Position[] [duplicate]

I am in trouble with Position, Although my example works as expected it throws a warning. Position[{{a,b},{a,c},{a,b}}, _?(#[[2]]==b&), {1}] During ...
3
votes
1answer
160 views

Easy way to perform multiplication of two 2x2 matrices, that contain list elements?

I have two 2x2 matrices, which elements are lists (so overall structure can be complicated). I need to perform matrix multiplication of these 2x2 matrices as if the elements didn't have its inner ...
3
votes
3answers
401 views

Compare 2 lists

I want to compare 2 lists. One is very large and I need to compare many times. Lets say Length[list1] I need to know how many times list1 occures in list2. Eg. list1={1, 0}, list2={1, 0, 1, 0, 1, 1} ...
3
votes
1answer
158 views

Programming for matrix manipulation

I want to write a programme which operates on nd x nd matrices. The programme looks the matrix as a n x n block matrix where ...
3
votes
2answers
67 views

Fast functional method for multiplying duplication numbers in a large list

Consider a list of symbols: mySet = {a, b, b, c, a, b, c, d}; I would like to form the product of duplication numbers. In the example above, I have 2 ...
3
votes
2answers
131 views

Partition a list dependent on consecutive list values

I have a list of 2D points which I partition every time the distance between consecutive list elements is bigger than a certain threshold. In a second step I select all the lists that start within a ...
3
votes
3answers
192 views

Working with calculations that depend on the previous value in a list

I'm trying to make calculations on a list that depend on the previous value. In my case I'm doing event detection - detecting the point where a value rises above some threshold for the first time e.g....
3
votes
1answer
127 views

How to efficiently select elements from a Hash?

How can I write an efficient version of the following selection statement: Keys[Select[hash, # < constant &]]; // AbsoluteTiming hash can be made from: <...
3
votes
1answer
1k views

Select row from a table by column value [duplicate]

I have the following: animals = {{dog, black, 200}, {cat, white, 100}, {moose, brown, 500}, {zebra,black,100}} If this came from a SQL table called animals, ...
3
votes
2answers
152 views

Change all values of a series to positive values

I would like to change all values of a series to positive values. I refer to my previous question, answered in the most part, very elegantly by RunnyKine. However, there remains a slight glitch that ...
3
votes
2answers
194 views

Write list of polynomials as a matrix of coefficients times a list of monomials

I have the following problem: given a list of polynomials P = {p1, ..., pn} on the variables x[1], ..., x[n], find a list of ...
3
votes
2answers
136 views

Incrementally revealing Grid (or TableForm) entries

I have a Grid (or TableForm) object like this ...
3
votes
1answer
937 views

A rotation-like transform on a matrix

Do not be confused with comments, those are for previous version of the question - Kuba Imagine I have a matrix of the form: ...
3
votes
1answer
201 views

Combining the items with common available dates from two lists [duplicate]

I have two lists of data including dates such as data1 = {{{yy, mm, dd}, a}, ...} data2 = {{{yy, mm, dd}, A}, ...} There are some missing dates from each list, ...
3
votes
1answer
425 views

Removing sublists containing elements from another list's sublist

Let there be two lists that have sublists: a[] = {{1, 2}, {1, 2, 3}, {2, 3, 4, 4}, {3, 4, 4, 5}} and ...
3
votes
2answers
331 views

Deleting a row or column of an adjacency matrix while maintaining the associated label

I am currently working with a weighted adjacency matrix for a directed graph, and it contains several 0 columns and rows. With the unaltered matrix, I am able to monitor the relations between vertices ...
3
votes
1answer
217 views

How to efficiently take complement of two big lists?

I have a giant list l1 and some smaller lists l21, l21, ..., ...
3
votes
1answer
286 views

How to partition MatrixPlot graphics?

Is there an easy approach - hopefully built-in - to partitioning MatrixPlot graphics into rows or columns (or both) of graphics sharing the same underlying options? ...
3
votes
1answer
350 views

n-fold symbolic integral in Mathematica

I am trying to compute symbolically a n-fold integral (n is a parameter of a function) over, say, the cube [0,a]^n. My code looks like this ...