Sorting a vector of (double precision) reals and obtain their order
- by Philipp
Hello everyone,
in C++ would like to sort a lengthy (2^20) vector of reals, obviously sort() does the trick. Having used R before I was used to the nice order() function which yields the permutation that leads to the sorted vector. Probably someone has done this in C++, maybe it's just my weak google-Fu that prevents me from finding it. And yeah, obivously my C++ newbness could stop me from spotting something straightforward.
Example:
x = {24, 55, 22, 1}
then the permutation
perm = {3, 2, 0, 1}
maps the original x to the sorted x in ascending order.
I can probably implement some bubble sort which does not only sort x but performs the same transpositions on the vector {0,1,2,...} and outputs both, but I believe someone must have thought about it and especially have done it efficiently.
Thank you very much, Philipp
