All combinations of the sum of 2 columns

I am looking to combine each of these columns to find the greatest x. I need to check every combination of the two columns that are being subtracted from eachother. Im only ever going to be comparing 2 columns together at once. After x has a new matrix I'm going to pull max to continue. This is a simplified version of my code, I have many columns that I am pulling from excel to compare.

a = [29;31;34]  
b = [31;31;31]  
x = (b-a)       % all possibilities for b-a

Answer 1

[Torsten]

a = [29;31;34].'  ;
b = [31;31;31]  ;
x = b-a

x = 3×3

2 0 -3 2 0 -3 2 0 -3

xmax = max(x(:))

xmax = 2

[Walter Roberson]

The max will be max(b)-min(a) or max(a)-min(b). If you use bounds() you can calculate these efficiently.