Different computing results with MATLAB in different machines

I have run the same program with MATLAB in different machines, the results between them are pretty similiar with each other. Maybe the deviation between them is below 1E-14. Here I have two questions to ask: 1. What factor leads to the different between two results in different machines. Can I avoid it? 2. Considering an example:I have two "pretty similiar" matrixes and the deviation is below 1E-14 for every element in two matrixes. What about the relationship between the eigenvectors of the two matrixes? Quite similiar or not? Thanks!:)

[Adam]

Different machines will always have the potential to give different results for a variety of reasons. If the two machines have the same specification then as far as I am aware this should not happen, but otherwise the different specifications can lead to different results.

1e-14 is generally considered to be equivalent to 0 though unless all your data is of the order of, for example 1e-12.

Even on the same machine you can get differences like this for maths operations which should, theoretically, give equivalent answers.

Eigenvectors should not be affected by this unless, again, the magnitude of the data you are using is of an order of magnitude such that 1e-14 is a significant percentage of it.