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

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10
votes
6answers
592 views
3
votes
0answers
80 views

Kernel crashes when computing finite difference mixed derivative with respect to y & z but works fine when computing with respect to x & y or x & z?

I am using Mathematica 10.4.0 on Ubuntu 16.04. I am trying to solve a set of differential equations using finite difference method on an NxNxN cubic grid (x, y, z directions). I am getting a weird ...
1
vote
1answer
83 views

Use Map on a Function with two variables

I am new to Mathematica and I would like to find out how to use Map on a function with two parameters such as: ...
4
votes
3answers
279 views

Enforce monotonicity in a list

Suppose I have a list containing pairs of complex numbers. For example: ...
0
votes
0answers
62 views
1
vote
3answers
339 views

Matching the order of a master list of lists from a random list of lists

Using Mathematica 9, I have 2 lists of lists one master with dimensions {300, 6}. The second is some random order but has the same first ...
3
votes
2answers
102 views

How to generate a limited number of tuples of a list and not all?

I have a question for which I couldn't find an answer: how can we generate only a given number of tuples of a list and not all of them? For instance, I want to have only the first two 3-tuples of <...
1
vote
2answers
76 views

How to repeat a set of operations on a single data set?

I am very new to Mathematica and I just couldn't figure out the solution for the following problem. I am trying to iterate the following functions for 10 times. For instance, "a" to "fullData". The ...
1
vote
2answers
108 views

How Do i Extract Only The Coordinates xyz (Number) From This Log file

this Log contains the information of all coordinates of many atoms in a molecular dynamics simulation for a long sequence of time steps, along with some extra information other than the coordinates. ...
3
votes
4answers
257 views

Duplicating and arranging a list

I have a list, {a,b,c,d,...,z} And I want to duplicate that list n times such that, {a,a,a,b,b,b,c,c,c,....z,z,z}. I ...
1
vote
0answers
49 views

List manipulation, averaging over lists and fidelity

I want to create vectors from a function poly[α_, β_, δ_, ϕ1_] were several variables (α, β, δ) are randomly sampled from a unit sphere. Then I want to vary another ...
0
votes
2answers
66 views

Plotting cicle using ListPlot

How can I plot circle plot with ListPlot function or how to organize data to produce circle plot from ListPlot function ? If u do something like this ...
3
votes
1answer
112 views

Replace list element with element from another list based on condition

I Have a list on integers and another list of "duplicates". E.g. start={{3},{1},{2},{4}}; duplicates={{1,4,7},{5,6}} I would like to substitute each element of ...
0
votes
3answers
139 views

Creating Average Grid data from Co-ordinate and value data

Consider a list: ZXV = {{z1, x1, v1}, {z2, x2, v2},........................} where $z$ is Z co-ordinate, $x$ is X co-ordinate, $v$ is the value at the point $i$....
0
votes
1answer
33 views

Iterating KroneckerProduct[] and returning the result from a function

I am trying to write a function which will take a matrix m and an integer i as inputs. Then it will compute the Kronecker product of m with itself i times and return the result. The code is as follows....
1
vote
1answer
86 views

How to determine distance of periodic features in measured dataset

I have a list of x- and y-values associated with a measured height (z-values). Part of the list is plotted below. As you can see, there is a periodic arranged structure, namely a cross. Now I would ...
0
votes
0answers
29 views

factoring a phrase of matrix elements and calculating main eigenvalues

I have a question containg two parts: 1-If we have a matrix as ...
2
votes
3answers
236 views

How to use Select with lists

I am trying to do: Select[minimus[[6]], #1[[2]] < (min[[6]] + emin[[6]]) &] applied to all elements of minimus, ...
6
votes
3answers
341 views

Indicate minimal path sum

Described on the page: http://www.mathblog.dk/project-euler-81-find-the-minimal-path-sum-from-the-top-left-to-the-bottom-right-by-moving-right-and-down/ It is an example of the solution indicated in ...
0
votes
1answer
49 views

How to pad numbers to the border of the Matrix?

I want to pad the numbers,but it throws an error Part::partw,so I use Quiet to suppress this error. ...
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 ...
6
votes
1answer
46 views

Heading in Table Form Question

I have: modadd = Table[Mod[i + j, 3], {i, 0, 2}, {j, 0, 2}]; TableForm[modadd, TableHeadings -> {{0, 1, 2}, {0, 1, 2}}] Which produces: How can I put a ...
3
votes
4answers
184 views

select elements in a list

I am new in Wolfram Math and I need a help in making a simple program. Let's suppose we have a list: list = {{1, 11}, {2, 7}, {4, 2}, {7, 9}, {-2, 3}, {-1, 10}}; ...
0
votes
4answers
51 views

insert elements into 2 D array [duplicate]

say I have a 2 dimensionsal array like a={{1,2,3},{4,5,6},{7,8,9}} and a vector like v={10,11,12} I want the result to be ...
4
votes
1answer
108 views

UpTo for negative indices?

The symbol UpTo emerged as a sort of "safe take" in version 10: Take[{1, 2, 3}, UpTo[4]] (* Out: {1, 2, 3} *) But it wasn't ...
2
votes
2answers
83 views

Group Datasets and take minimum/maximum

Good Morning I have the following dataset: And I try to reach this output: key: only one row per key text: join all texts of the rows with the same key (but no duplicates) min: take the lowest ...
8
votes
2answers
98 views

For loop works at top-level but not in a function

Why does this work: For[i = 1, i <= Dimensions[list][[1]], i++, list = Insert[list, i, {i, 3}]] But this doesn't: ...
4
votes
3answers
137 views

Alternative forms to Table for iterating over replacement rules

I have a multivariate polynomial x. I get coefficients of various monomials using CoefficientRules, which returns a list of ...
9
votes
1answer
203 views

Fast implementation of Metropolis-Hastings update with multiple sets

This is an optimisation question rather than something I am unable to do. I have a naive, primitive working version of the code (I submit it below) but I am trying to make it work faster. I am asking ...
-1
votes
3answers
80 views

Create table of elements which belongs to specific sets

I would like to produce elements (preferably by Table or For-If commands) that they belong to specific sets. For example I want to write positive integers from 1 to 100 such that they are $2 \pmod 3$, ...
3
votes
1answer
290 views

Minimize sum of array elements subject to conditions

I have array where each point at different times are shown parameters ...
3
votes
2answers
80 views

Generating a sequence of lists [closed]

I have learnt how to generate a sequence of numbers, but now I come across a question whether it is possible to generate e sequence of lists. Say, I would like to generate {1},{1,2},{1,2,3},...,{1,2,3,...
9
votes
3answers
350 views

Give a element rank list of a list

SeedRandom[417] list1 = RandomChoice[Range[22, 28], 4] {22, 24, 26, 23} We can get the rank list ...
1
vote
1answer
54 views

Rearrange the list with some rules

I am trying to solve physic problem on operators which are not commute. However, I am not good at coding, so I am having some problem with Mathematica code. Let's define my list such that ...
0
votes
2answers
63 views

How to prove that an equation can be divided by any n?

I'm new to Mathematica and came across with the problem. I can't prove that (for example) 2*n is always even no matter what n is....
-1
votes
1answer
46 views

How to graph the max and min values of a sheet?

Hi I just start working in Mathematica version 10.3.1 and I want to graph a sheet of data that I created in Excel (yeah i use Windows). The problem is i have so many data; 200 columns and 50 row of ...
-1
votes
1answer
50 views

Generate list of first 100 prime number? [closed]

I know how to generate a list of prime numbers up to a limit, but how would I generate the first 100 prime numbers in a list?
3
votes
2answers
102 views

Using “Outer” with “ChineseRemainder”?

I'm looking to build a $7\times3$ matrix using ChineseRemainder. Trying to use ${0,1,2,3,4,5,6} \pmod 7$ and ${3,15,21} \pmod {30}$ so that the first element of ...
3
votes
2answers
71 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 ...
5
votes
3answers
133 views

How to partition a set with a condition on subsets?

I want to partition a set of $n$ elements into $k$ subsets with a condition For example: partitioning this set {1,...,5} into 3 subsets with this condition: if $|i-j|<d$ then $i$ can't be with $j$ ...
0
votes
1answer
66 views

Append[] is not working for empty list [duplicate]

I am trying to create an empty list and add an element but the list is not being populated. My code ...
0
votes
1answer
92 views

How to turn a subroutine into a function?

I've written a subroutine that takes in 6 matrices and after some manipulation returns back 3 new ones. I will use this subroutine fairly often in this notebook so I think it would be easier to turn ...
0
votes
0answers
40 views

Do[If[ *stuff* ]*arguments*]: Increasing range over which Do iterates changes results of If?

Summary: If I run the same Do[] expression but with the variable(s) over which I am iterating taking on more values (but same increment), an If statement inside the Do[] evaluates as false a few times ...
6
votes
2answers
366 views

Performance of calculation of means squared displacement

How can I improve the performance of the following code which calculates the mean squared displacement for coordinates stored in data? Here for each time difference ...
0
votes
1answer
41 views

Help with limiting output

I wrote this program on Mathematica (which I am very new to): ...
11
votes
4answers
489 views

How do I extract a matrix of only positive numbers given a set of assumptions?

I want to divide a matrix: mat = {{a, 0, -b}, {d, a, 0}, {0, 0, -a}} with the following assumptions: ...
10
votes
4answers
297 views

Convert elements of list to string

how easily can I convert elements of this list to string. If I have output like this: {{M, 1, 0, 0, 1, 1, 1, 0}, {A, 0, 0, 0}} And I want something like this: <...
0
votes
1answer
81 views

ListPlot and Show n plots from two lists with large n

For the context, I have been dealing with Random Matrices and Dyson Brownian motion. I have two lists, the first one contains the number of steps, so ...
4
votes
3answers
135 views

Replicate sublist in new list

If I have a list of lists $a$ and a list of occurrences of each sublist $n$ a={ {1,1,1}, {2,2,2}, {3,3,3} } n={1,3,2} what is the most efficient way to get the ...