# Questions tagged [map]

Questions about applying functions or operators to expressions, especially constructs that take advantage of Map (/@) functionality.

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29 views

### Contour plot of a constant y?

I have the following data points, ...
38 views

### How to separately pass elements of a 3D list as part of the arguments of a function

Hi I have a function which its arguments have the form F[a,b,c,d,e] but the 2nd to 4th arguments are in a list of the form R={{{b,c,d},{e,f,g}},{{h,i,j},{k,l,m}}} how can I pass these elements as ...
39 views

### Contour plot with x, y and z values?

I have x , y and z as x = List[1.355, 1.357, 1.359, 1.36, 1.357, 1.355]; and ...
31 views

### Converting 1D map into first order differential equation for bifurcation diagram code

I have existing code to plot bifurcation diagram for coupled first order differential equations. It seems to work for coupled differential equations. To test the code further, I use the simplest ...
31 views

### Trouble with bifurcation of differential equation

The code for bifurcation is written in such a way that it will allow plot bifurcation for any number of differential equation. Thus I am trying to avoid maps and iterations. Unfortunately it does ...
62 views

### Add gaussian noise to 2D Point

I implemented a program for a camera calibration in Mathematica with with prototypical data to see if my calibration works. Here I converted 3D object coordinates into 2D sensor coordinates. I have ...
28 views

### How to make a manipulatable map that can change color?

I want to color the world map differently according to how much the number of each country. For example, USA using renewable energy for 20% should be colored lighter than Canada using renewable for 50%...
22 views

### Adaptation of existing code to multivariable system

I am trying to adapt the existing code from "Mathematica package for analysis and control of chaos in nonlinear system" by Gutierrez. This existing code calculates the Lyapunov Exponent by ...
52 views

### How to find N most populous cities in each state with TakeLargest and Entity Functions without waiting forever using Caching?

I am interested in using Entity Functions such as EntityValue, FilteredEntityClass, EntityFunction, EntityClass, EntityList, and GeoEntities to help me find N most populous cities in each state. I ...
62 views

### Mapping data from 2 files imported

I'm not in prog major. This course is needed as an elective for another major. Thus any help is appreciated. DataA and DataB ...
243 views

### What's the difference between @ and /@? [closed]

The @ and /@ functions do the same thing: ...
75 views

### compiled function not mapable

I am currently working on speeding up a larger project and thus using FunctionCompile. I have come across the issue that a manual input of list elements produces a valid results, however if I try to ...
101 views

### How to split many controls in Manipulate into multiple columns (saw some potential bugs)

I need to use Manipulate[] with many controls, because I have around 40 parameters which I want to be able to alter. Since the number is too large, I want to split these controls into multiple columns,...
73 views

### How to use Select and MemberQ together with Map correctly?

I have a list with quite a few elements. Each element is a rule of the type vector-> number such as {1,2,3,4}->1.435 and ...
53 views

### Map a function that uses the lists indices as arguments

Suppose I have a function f[x_] that I want to Map over somelist (assumed to be one ...
104 views

### How to limit the cpu usage of Mathematica?

I am runing mathematica with ParallelMap[], on a win10 computer with 8 physical cores. The cpu usage always rocks up to 100%, though ...
59 views

### Evaluate a function with 3 different variables for the whole list of each variable

I have a function with 3 variables f[t1,t2,t3] Each function has a list of values ...
39 views

### How to map the outputs to different output lines?

I have the following code GraphIt[n, n2, IR, #] &/@ vanishpts where the function GraphIt print something, and returns a graph. I don't want my outputs to be ...
71 views

### Considerations for Compiling and Parallelizing Code Outside or Inside Map[]

Assume f as well as Map[f,list] are parallelizable and compilable, such that parallelization and compilation give significant ...
85 views

### Mapping list elements without using Table function

How could I generate the following list of points using some function or mapping without using the table function. ...
65 views

### How to Map over a BlankSequence? [closed]

I would like to replace any function f[x, y, ...] in a certain expression with the same function with all its arguments squared, i.e. ...
158 views

### Curious about Mapping over multiple multiple arguments [closed]

To my shame, I have discovered the power of Map quite recently and since then I have been using it more and more. But increasingly I find myself trying to use ...
66 views

### How to digitize a vector field?

Is there some way that I can digitize both the direction and the magnitude of a vector field accessible in JPEG format? To clarify what I mean, I want to have the numerical value of: 1)magnitude and 2)...
67 views

### Applying transformation rule for corresponding indices?

I have two lists, that looks like below list1 = {a, x, b, x, x, c}; list2 = {2, 3, 4, 5, 6, 7}; Any time there is an x in the ...
70 views

### Iteration limit exceeded

I am trying to adapt the following piece of code (coming from this answer): ...
75 views

### how I should use MovingMap on a Dataset?

I am aware of How would I use Map on a Dataset column? still I cannot see how I should use MovingMap on a Dataset. Even the ...
38 views

### Recursive addition of vector list to last elements of vector lists

This question refers to an extension of Add list of vectors to list of vectors recursively . I tried hard to complete the problem but now I got stuck. I have vectors ...
124 views

### bind specific 'Slots' to specific 'Map'

Is it possible to construct a pure function using multiple slots, with the following concept :       Binding   specific slot    to    specific apply or map For example : In this example, To ...
122 views

### Restrict kinds of heads when dealing with level concept

In Map[(# + 7) &, {a, 3 b, {c, d}, e}, {2}] Out {a, 10 (7 + b), {7 + c, 7 + d}, e} But I want feature like ListMap : ...
41 views

### calculate differences of a list using slots

I want to calculate the differences between the numbers of a list. One way to do that is using 'Differences'. For example: L = {1, 3, 6, 9}; Differences[L] this ...
41 views

### How to prevent small locations from being plotted as points when using GeoListPlot?

When a location is too small, GeoListPlot marks that location using a point on the map. For example, ...
69 views

### Manipulate mapping on lists

For some function f, consider the following expression: ...
929 views

### Metropolis-Hastings Algorithm - Significantly slower than Python

I would like to code a Metropolis Hasting algorithm and thought I would get the general scheme of things going with a toy example. I think I got it running but my Mathematica code runs significantly ...
47 views

### How to change Point options when using Map?

I want to change the point size of the points I am plotting in the code below, but wherever I place the PointSize[] option it doesn't like it. The code is part of a larger program, which generates a ...
45 views

### loop execution time difference after Map operation

I am box filtering data from a DNS simulation. When filtering the original data read from a file, this is fast. When filtering a function of these data after applying Map, it is 10 times slower. If I ...
90 views

### Optimal way to evaluate a function over many points

This piggy-backs on my previous question: Parameter space search routine is too fast? I am looking for a fast way to evaluate a symbolic list over many points. So lets say I have a list of symbolic ...
46 views

### How can I plot various points on a world map and compare distances?

How can I plot various points on a world map and compare distances? For example, the distance between Jerusalem and Westford, MA compared to the distance between Westford, MA and Recife, Brasil? Then ...
186 views

### Maximum of all distances between any pairs of vertices of a random triangle

Given a set $S_n$ of $n$ points selected uniformly at random in a $d$-ball, I want to estimate the average length of the longest side of a triangle having as vertices any three distinct points of $S_n$...
40 views

### Replace Table with a fast matrix operation to create for matrices A, B the tensor (b_{ij}A) and similar questions

I have two (nxn)-matrices A=(a_{ij}) and B=(b_{ij}) and I'd like to create the (nxnxnxn)-List C=(b_{ij}*A) so e.g. ...
188 views

### Nested lamdas: MapThreading a MapAt lambda

Consider a set of (here) 3 series ...
82 views

### Key-dependent maps preserving association

Suppose I have some association a0 = <| key1 -> val1, ... |> and some function f[key, val]. I'd like to produce the ...
29 views

### Changing PlotStyle while mapping ListLinePlot at several datasets [closed]

Assume that I have several datasets in a matrix and I want to plot them using ...
257 views

### How to write a positive function as sum of positive terms only

A multivariate polynomial function can be written in a certain form (x^m (1-x)^n y^k + ... ) if the function is Positive in the whole domain and contains a finite ...
50 views

87 views

### Multiple Calculations in a condition

I want to add and subtract 3 from a list. pos = {82,84} If[# > 3, (# - 3) && (# + 3)] & /@ pos the output I want: ...
77 views

### Removing curly brackets in an argument of ArcTan [closed]

I have list of number pairs l = {{1, 0}, {1, 1}, {0, 1}, {-1, 1}, {-1, 0}, {-1, -1}, {0, -1}} of which I want to take the ArcTan ...
174 views

### Why Does Parallelization Not Speed Up these Seemingly Well-Parallelizable, Simple Functions?

Original Example Consider function f, a parallelized version fPar, and a coarsest-grained parallelized version ...