I have two arrays:
a = [[1,2],[3,4]];
b = [[5,6],[7,8]];
I want the resultant array to be their sum, i.e.,
c = [[6,8],[10,12]];
Would there be an elegant way to do so?
Note:
I currently know that to simply add a = [1,2] with b = [3,4] to get c = [4,6] I need to do
c = [a,b].transpose.map{|x| x.reduce(:+)};
but I'm not sure how to, if possible, extend this to my problem.
a.zip(b).map { |x,y| x.zip(y).map { |s| s.inject(:+) } }
c = [a, b].transpose.map{|ary| ary.transpose.map{|ary| ary.inject(:+)}}
An alternative, with better expression for manipulating numbers, would be to use 'narray'
require 'narray'
a = NArray[[1,2],[3,4]]
b = NArray[[5,6],[7,8]]
c = a + b
. . . yes really, c = a + b and it is much faster too.
You do pay for this though - NArray expects all the elements to contain the same type of object. If that's the case, and especially if your real-world problem has much larger matrices, then I highly recommend narray for handling this kind of data