3
votes
2answers
83 views

Wrapping Interval Notation for Take

I'm trying to implement the solution to a math problem in Mathematica, but my code can't handle a particular boundary case. I think that I could implement a function that would do what I want it to, ...
1
vote
1answer
64 views

Remove curly brackets _completely_ to map a function to the elements of a list [duplicate]

Most list manipulations can be done with Flatten, Partition and Take. I didn't managed to ...
-2
votes
4answers
183 views

Compare elements in a list

Assume that there are three different points in x-y coordinate like: p1={4, -1}; p2={5, -2}; p3={1, 5}; In order to compare these points to each other in a ...
2
votes
3answers
113 views

Speeding Up Replacing of Labels in Large Matrix?

I am Mathematica novice and am trying to find a fast way to replace labels in some rather large matrices (512x512 or 1024x1024) that have resulted from segmenting images with WatershedComponents or ...
19
votes
3answers
640 views

DeleteDuplicatesBy is not performing as I'd hoped. Am I missing something?

Déjà vu: a new-in-v10 function should provide a better solution to an old problem, but my enthusiasm is curbed when I run timings. This time the function is ...
0
votes
0answers
53 views

deleteduplicates Delete elements of a list [duplicate]

I have a math problem about Mathematica, I am looking help from you. I hope that you could help me. The Math Problem: list= { {0,0,1},{1,0,0},{0,1,0} ,{1,2,3}}; ...
1
vote
1answer
89 views

Using Map in a function definition

I want to calculate the hessian of a matrix. So each element gets replaced by a 2 by 2 matrix. ...
0
votes
2answers
88 views

Defining a function as a sum of several Gaussians

I have a function that is a summation of several Gaussians. Working with a 1D Gaussian here, there are 3 variables for each Gaussian: A, ...
0
votes
2answers
230 views

How to pass a list as function argument?

I have the following function lFreqPhylo[a_, Q_, b_, p_] := Sum[Log[freqFunction[r[[p]][[i]], L[[p]][[i]], a, Q, b, {i, 1, nbranches[[p]]}]; The objects L, r ...
1
vote
1answer
72 views

Apply function to output of previous function

I am trying to write a function that takes 3 tuples. Each tuple contains two lists which are first divided. This results in 3 lists. Then I want to take the Mean of all the columns. I can do this ...
3
votes
0answers
78 views

Why does Part behave like it transposes lists? [closed]

From the documentation of Part: Part[expr,i,j,...] is equivalent to expr[[i]][[j]]... ...
1
vote
1answer
116 views

How to define a list that contains all primes less than x?

how can I define my own list in which I have all primes less than x?
0
votes
0answers
43 views

Plot two functions of two variables against each other [duplicate]

I have two functions f1(n,m) and f2(n,m) but the issue is that f1 generates many values say ...
0
votes
0answers
130 views

A problem with functions and Infinite expression 1/0 encountering

Following code (function) makes integrals and then replace f[x] with Cos functions and calculate the definite parametric ...
0
votes
1answer
111 views

A problem with set values

The following code is just an example to clearly explain my problem. Assume that : ...
3
votes
3answers
211 views

Finding a better way to define a matrix

I first defined a 171x171 matrix containing only zeros and then replaced 18 specific rows with nonzero entries. The other $153$ rows will be average of $2$ of the existing $18$ rows. Rows $2$ ...
1
vote
3answers
178 views

How to update a list in a function in each iteration

There is a list with numbers 1 to 8 ( p1 ) and another list (j) which contains 4 numbers which shows different 4 positions of ...
0
votes
1answer
92 views

Populating an array with outputs of a function [closed]

I have searched, but didn't find much help on my issue. I have an optical physics problem that I'm working on .. ...
1
vote
2answers
110 views

How to work with lists of functions

I have some lists of interpolated functions and I want to know if there is an easy way to operate with them. A simplified example: ...
0
votes
1answer
88 views

mathematica apply list of functions to the same arguments [closed]

How can I apply list of functions to the same arguments? e.g. ApplyFun[{fun1,fun2,fun3},{arg1,arg2}] I looked here and could not find: ...
0
votes
0answers
28 views

Problem with slot in If statement [duplicate]

I am struggling with slots, In this case I have a function int which gives either true or false. When it gives true, I want ...
0
votes
1answer
65 views

How to use ImageMultiply[] over a list of strings?

I'm trying to do the following: ...
6
votes
4answers
262 views

Using an ellipse as a threshold for Nearest function

The Nearest function can receive as a threshold parameter a radius to look for elements inside that. From the documentation: ...
0
votes
2answers
105 views

Handling output that was returned unevaluated from a function

When evaluating functions, including those described in this post, how do Mathematica users handle values returned from a function that are unevaluated? For example (based on 1): ...
15
votes
4answers
1k views

Moving maximum function?

How can I construct a moving maximum function? For example, if I have a list of 12 values: { 5, 6, 9, 3, 2, 6, 7, 8, 1, 1, 4, 7 } and I want to maximize over 3 ...
3
votes
2answers
374 views

How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)

I've been working on this research problem for months with some success by no global/proper solution to the problem. So I have square, Hermitian matrices of various sizes ($8,20,38$ dimensions) with ...
1
vote
2answers
118 views

Add a column to a matrix as a function of the other columns

I was wondering if its possible to add a column to a matrix by a formula that uses all other columns, like this: ...
6
votes
2answers
184 views

how recover lost data of coordinates from contourplot of mention data?

I have made Contour Plot for a lot of data, like this ...
15
votes
2answers
2k views

Is there an equivalent to MATLAB's linspace? [duplicate]

Does Mathematica have an equivalent to Matlab's linspace? I want to make a list with "start", "stop" and "number of points". What is the neatest way of doing this?
-1
votes
2answers
223 views

How can I extract when a select condition is met in a do loop the value of the iterator?

I use the following code to find out the number of consecutive prime numbers using a formula $n^2+n+i$ found out by Euler (starting from n=0): ...
14
votes
5answers
350 views

Partitioning a list of numbers the Mathematica way

I have two sorted lists, one list will be called the "fences" and the other the "values" Fences could be: $\{1, 5, 9, 14\}$ Values could be $\{-1, 1, 3, 4, 6, 9, 10, 13, 14, 15\}$ I want to ...
9
votes
1answer
313 views

Two ways of map a function on the list: Which one is faster?

There are 2 ways to make a function listable on the list: Use Map or use SetAttributes. My question is, which one is faster, ...
1
vote
1answer
189 views

Split Lingustic(IPA) at Words Unique Sounds

How might I split a word at each IPA of each unique sound. For example {"pray", "wade"} (* {{"p","r","ˈeɪ"}, {"w","ˈeɪ","d"}} *) ssch answered a question here ...
0
votes
4answers
62 views

Don't understand why Do-loop index is not evaluated in Play expression

So here is some weird behavior: When I create a list inside a loop whose elements are Play functions, with arguments that depend on the counter, it is as if the counter is being stored symbolically, ...
3
votes
0answers
90 views

Gather dependency on list order?

I get intrigued about Gather behavior on this post. I thought that Gather was invariant under list order? Here is the result I ...
10
votes
5answers
494 views

How to find first list element that differs from average of N previous elements by more than a given amount?

Given a list of real numbers, I need to write a function that returns the value of the first element in the list that differs from the mean of the previous $N$ elements by greater than $P$ standard ...
1
vote
1answer
190 views

Map a function conditional on elements at multiple relative positions in a list

I figure this question has many solutions, and if an answer already exists it would be nice just to be referred to it. I need a function that 'maps' over my list and produces a list of equal length ...
2
votes
1answer
170 views

How to compute a discrete histogram of a list [duplicate]

I'm trying to compute the discrete histogram of a set of values. By histogram I mean the absolute frequency a value appears on the dataset, by discrete I mean the values are from a discrete set, e.g. ...
1
vote
1answer
153 views

Create continuous function from list

I have a list of data (measured per day) that I want to use as imput for another equation (say f). The problem is that the input I need for f needs to be a continuous function of time. Is it possible ...
0
votes
0answers
63 views

Defining functions in a loop [duplicate]

I have a symbolic solution to a linear system with respect to some variables a[i,j] which depend on a parameter t. sol=Solve[...,Table[a[i,j],{i,0,n},{j,0,n}]] I ...
4
votes
1answer
336 views

Counting the number of operations performed during a calculation

I need to know how can I count the number of operations performed during a calculation of a CompoundExpression. In some of these expressions there are ...
3
votes
2answers
646 views

Function returning Null along with other unexpected expressions

When I use some function, at the end along with the output I get some NULLs returned that I don't understand the reason for and are highly undesirable. For example, when I define the reversal of list ...
2
votes
4answers
796 views

How can I create a list of functions?

Can anyone tell me, how to create a list of functions? I've tried the following code, but it doesn't work. ...
2
votes
1answer
114 views

Flat function with repeated sequence

There are functions like Join[ ] that accept a variable number of arguments. Join is a flat function, as the order of arguments ...
6
votes
1answer
112 views

How does `LongestCommonSubsequence` work?

When I recently came across this posting about LongestCommonSubsequence I was curious about how the function worked. ...
5
votes
5answers
1k views

How to sum over a List

list = {11.5575, 11.397, 5.52734, 4.0878, 2.54815, 1.86652, 2.55028, 2.14952, 1.6242, 1.34117} I have a list of numbers. How do I make a function that creates a ...
18
votes
4answers
624 views

Accessing list elements by name

First, a bit of a long introduction to my problem: I only have a few weeks of Mathematica experience. I am creating a mathematica application that calculates some material properties of steel based ...
10
votes
5answers
716 views

Building a continued fraction

I've completed a problem that involves approximating $e$ by a continued fraction: $$\frac{N_1}{D_1+\frac{N_2}{D_2+\frac{N_3}{\ddots+\frac{N_k}{D_k}}}}$$ with the $N_i$ being the list ...
7
votes
4answers
569 views

How make f[{x,y}] evaluate as f[x,y]?

I frequently encounter the situation where I have a function of two real variables defined, e.g.: f[x_, y_] := 9 - x^2 - y^2 But then I need to feed into ...
3
votes
4answers
656 views

Extract function arguments

Is there a way to extract the arguments of a function? Consider the following example: I have this sum ...