3
votes
3answers
104 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 ...
0
votes
0answers
113 views

Improving the speed of evaluating Table with nested functions

I am a Mathematica novice working with a stack of 1024 x 1024 WatershedComponents (or MorphologicalComponents) label matrices ...
1
vote
1answer
83 views

Nest Replace Function with different rules

I have a table of data that I want to filter. Any value of zero in the table means that value was not calculated, so it should get populated with the tag "NC". Next the table is filtered for all ...
0
votes
1answer
43 views

Resolving Error: Mathematica evaluation order on Lists

I have a table that is 27 x 27, each entry corresponds to an element from the periodic table. I use the replacement rules in element list to allow me to convert a list of elements into a list of ...
0
votes
0answers
73 views

Improving a function that filters each table from a list of tables

I have written the following function which can take in a list of tables as an arguement, and then filters each one. The function I wrote is below, and the commands I combined are listed below the ...
4
votes
3answers
214 views

Conditional search along the columns of a matrix

I want to implement the following algorithm in Mathematica. Get element along main diagonal of a matrix. If the element along the main diagonal is positive, then return the positions of the elements ...
5
votes
4answers
301 views
9
votes
3answers
473 views

What is the most efficient way to map a linked list?

In order to work with lists effectively using common recursive patterns from functional programming, it's often most convenient to worked with the "linked list" representation, that looks like this: ...
4
votes
2answers
195 views

How to set up and minimize a large system of equations to resolve the individual components

I am trying to set up a system of 400*N equations to deconvolute spectral data for four different compounds. I monitored 400 different wavelengths in N solvents (3 solvents in this case). In order ...
1
vote
2answers
256 views

Mapping functions over multiple lists

I am not sure if this is a duplicate. Spent some time looking over list-manip questions. I’d like to know the Quickest Way to achieve the following Mapping of a function over multiple lists. ...
1
vote
1answer
164 views

How should I go about writing more functional and list based code? [duplicate]

I've heard that Mathematica is usually faster when the code is list-based and/or uses a functional paradigm. I'm still working on getting the hang of this; there are a lot of ...
0
votes
2answers
111 views

Where are the functional programming constructs: `every` and `some`? [duplicate]

Coming from other functional programming environments (e.g., Clojure) I've become accustomed to some functions that I haven't found equivalents for in Mathematica yet. The two I reached for last ...
1
vote
2answers
102 views

How do I operate on this list elegantly? [duplicate]

calibData = { {200, 10}, {100, 20} } MapAt[N, MapAt[Log10, calibData, {;; , 1}], {;; , 1}] I want to apply a base 10 Log to the first element of each tuple. ...
3
votes
1answer
175 views

Levels and slots

I am struggling with levels and #, if I understand this I think I will be able to grasp the entire concept. ...
12
votes
5answers
649 views

What's the cleanest functional-programming style way to perform this list operation?

I am looking for the correct method for accomplishing the unknown piece in the following code snippet: rolls = Tuples[Range[1, 4], {2}] ...
4
votes
4answers
464 views

Replace For-loop with functional code

I am very new to Mathematica. I have code written using for loops. I want to rewrite it using Map/Thread but I am not sure how ...
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
0answers
92 views

Optimized subset algorithm implementation

I was reading a paper from Mathematica Journal.It mentions a code for calculating subsets. ...
5
votes
3answers
168 views

All values for a function with two arguments without Outer

Given two lists $l_a = \{a_1, a_2, a_3\}$, $l_b = \{b_1, b_2, b_3, b_4\}$ and some function $f$ accepting two arguments, how can I produce a list of all values $f(a, b)$ for $a\in l_a$ and $b \in l_b$ ...
4
votes
6answers
214 views

Filter list with different list in it

I have a list like: {{{4, 14}, 1}, {{4, 15}, 1}, {{4, 16}, 1}, {{4, 17}, 1}, {{4, 18}, 1}, {{4, 14}, 3}, {4,15}, {{4, 16}, 2},{4,18}} Now I want to ...
1
vote
4answers
187 views

Order of operations for the Table function [duplicate]

Possible Duplicate: Using pure functions in Table I have run into a situation that I do not understand when trying to generate a nested list of pure functions. I have the following code. ...
4
votes
3answers
377 views

Generate a Combination of letters by a number

I'm trying to write a function f. example: ...
6
votes
4answers
1k views

Alternatives to While Loops?

I am using Mathematica to run a probabilistic simulation. Essentially, I have a list of members of a population (they only have one, numerical, attribute, so it's just implemented as a list of ...
4
votes
1answer
227 views

Timing differences between multiple executions of identical code

I have a list of pairs of numbers and I'd like to change the sign of the second element in each pair i.e. $(a,b)\rightarrow (a,-b)$. I'm sure there are many ...
11
votes
4answers
295 views

Thread a function over a list and with a non-atomic 2nd parameter?

From the documentation, Thread's behavior on functions where the first parameter is a List and the second is an atomic expression, is this: ...
27
votes
12answers
1k views

Map a function across a list conditionally

It seems that this is a really basic question, and I feel that the answer should be obvious to me. However, I am not seeing. Can you please help me? Thanks. Suppose I have a list of data ...
17
votes
3answers
831 views

Using pure functions in Table

I need a table with the elements made of pure functions and list elements. This is a simplified example: I need a list as: ...
14
votes
2answers
514 views

Reproducing nested loops using Map?

I keep producing bits of code like the following: ...
4
votes
1answer
230 views
16
votes
1answer
327 views

Are there advantages to using additional arguments of common functions rather than alternative ways of calculating with lists?

(Apologies for the long question title.) One of the interesting, if sometimes confusing, things about Mathematica is that there is always more than one way to do things. Even intermediate users can ...