Tagged Questions
8
votes
1answer
164 views
Efficient way to solve equal sums $x_1^k+x_2^k+\dots+x_5^k=y_1^k+y_2^k+\dots+y_5^k$ with Mathematica?
I need to solve the system of equations, call it $S_1$, in the integers
$$x_1x_2x_3x_4x_5 = y_1y_2y_3y_4y_5$$
$$x_1^k+x_2^k+\dots+x_5^k=y_1^k+y_2^k+\dots+y_5^k,\;\; k= 2,4,6$$
I used a very ...
2
votes
2answers
120 views
How to populate a table using a rule replacement
I am trying to populate the rows and columns of a table by using a rule replacment.
To generate a table that looks like this
For example Sc would be row 1, column 1.
An example of a record looks ...
18
votes
3answers
548 views
Emulating R data frame getters with UpValues
What's the best way to emulate R's data frames functionality? This includes the ability to select rows and columns in a 2-dimensional table by the string identifiers positioned typically in the first ...
4
votes
2answers
193 views
Access pairs of vectors, rather than the matrices, in partitioned data structure at a levelspec
I have some old code to analyze correlation between 2 time series by looking at windows of different lengths shifting across the time series data. The code:
gets 2 sets of time series data (in ...
5
votes
2answers
215 views
Extracting parts of nested lists of rules using a syntax similar to JsonPath or Xpath
Given an example data set:
...
4
votes
1answer
166 views
What's the most intelligent way to store the information of a selfmade graph?
I have a very long list of element, say $a1,a2, a3$,..., and they are all connected in that each is the child of many parents. E.g. $a74$ is associated with $a2,a55,a71$, and also contains ...
2
votes
1answer
192 views
Conditional Data Selection, efficiency
Building up on the solution proposed here : Simplifying nested If statements
You can find here the data set : allGazes.dat
...
